Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

77 files changed, 24559 insertions, 0 deletions

diff --git a/browser/components/newtab/test/unit/common/Actions.test.js b/browser/components/newtab/test/unit/common/Actions.test.js
new file mode 100644
index 0000000000..32e417ea3f
--- /dev/null
+++ b/browser/components/newtab/test/unit/common/Actions.test.js
@@ -0,0 +1,236 @@
+import {
+  actionCreators as ac,
+  actionTypes as at,
+  actionUtils as au,
+  BACKGROUND_PROCESS,
+  CONTENT_MESSAGE_TYPE,
+  globalImportContext,
+  MAIN_MESSAGE_TYPE,
+  PRELOAD_MESSAGE_TYPE,
+  UI_CODE,
+} from "common/Actions.sys.mjs";
+
+describe("Actions", () => {
+  it("should set globalImportContext to UI_CODE", () => {
+    assert.equal(globalImportContext, UI_CODE);
+  });
+});
+
+describe("ActionTypes", () => {
+  it("should be in alpha order", () => {
+    assert.equal(Object.keys(at).join(", "), Object.keys(at).sort().join(", "));
+  });
+});
+
+describe("ActionCreators", () => {
+  describe("_RouteMessage", () => {
+    it("should throw if options are not passed as the second param", () => {
+      assert.throws(() => {
+        au._RouteMessage({ type: "FOO" });
+      });
+    });
+    it("should set all defined options on the .meta property of the new action", () => {
+      assert.deepEqual(
+        au._RouteMessage(
+          { type: "FOO", meta: { hello: "world" } },
+          { from: "foo", to: "bar" }
+        ),
+        { type: "FOO", meta: { hello: "world", from: "foo", to: "bar" } }
+      );
+    });
+    it("should remove any undefined options related to message routing", () => {
+      const action = au._RouteMessage(
+        { type: "FOO", meta: { fromTarget: "bar" } },
+        { from: "foo", to: "bar" }
+      );
+      assert.isUndefined(action.meta.fromTarget);
+    });
+  });
+  describe("AlsoToMain", () => {
+    it("should create the right action", () => {
+      const action = { type: "FOO", data: "BAR" };
+      const newAction = ac.AlsoToMain(action);
+      assert.deepEqual(newAction, {
+        type: "FOO",
+        data: "BAR",
+        meta: { from: CONTENT_MESSAGE_TYPE, to: MAIN_MESSAGE_TYPE },
+      });
+    });
+    it("should add the fromTarget if it was supplied", () => {
+      const action = { type: "FOO", data: "BAR" };
+      const newAction = ac.AlsoToMain(action, "port123");
+      assert.equal(newAction.meta.fromTarget, "port123");
+    });
+    describe("isSendToMain", () => {
+      it("should return true if action is AlsoToMain", () => {
+        const newAction = ac.AlsoToMain({ type: "FOO" });
+        assert.isTrue(au.isSendToMain(newAction));
+      });
+      it("should return false if action is not AlsoToMain", () => {
+        assert.isFalse(au.isSendToMain({ type: "FOO" }));
+      });
+    });
+  });
+  describe("AlsoToOneContent", () => {
+    it("should create the right action", () => {
+      const action = { type: "FOO", data: "BAR" };
+      const targetId = "abc123";
+      const newAction = ac.AlsoToOneContent(action, targetId);
+      assert.deepEqual(newAction, {
+        type: "FOO",
+        data: "BAR",
+        meta: {
+          from: MAIN_MESSAGE_TYPE,
+          to: CONTENT_MESSAGE_TYPE,
+          toTarget: targetId,
+        },
+      });
+    });
+    it("should throw if no targetId is provided", () => {
+      assert.throws(() => {
+        ac.AlsoToOneContent({ type: "FOO" });
+      });
+    });
+    describe("isSendToOneContent", () => {
+      it("should return true if action is AlsoToOneContent", () => {
+        const newAction = ac.AlsoToOneContent({ type: "FOO" }, "foo123");
+        assert.isTrue(au.isSendToOneContent(newAction));
+      });
+      it("should return false if action is not AlsoToMain", () => {
+        assert.isFalse(au.isSendToOneContent({ type: "FOO" }));
+        assert.isFalse(
+          au.isSendToOneContent(ac.BroadcastToContent({ type: "FOO" }))
+        );
+      });
+    });
+    describe("isFromMain", () => {
+      it("should return true if action is AlsoToOneContent", () => {
+        const newAction = ac.AlsoToOneContent({ type: "FOO" }, "foo123");
+        assert.isTrue(au.isFromMain(newAction));
+      });
+      it("should return true if action is BroadcastToContent", () => {
+        const newAction = ac.BroadcastToContent({ type: "FOO" });
+        assert.isTrue(au.isFromMain(newAction));
+      });
+      it("should return false if action is AlsoToMain", () => {
+        const newAction = ac.AlsoToMain({ type: "FOO" });
+        assert.isFalse(au.isFromMain(newAction));
+      });
+    });
+  });
+  describe("BroadcastToContent", () => {
+    it("should create the right action", () => {
+      const action = { type: "FOO", data: "BAR" };
+      const newAction = ac.BroadcastToContent(action);
+      assert.deepEqual(newAction, {
+        type: "FOO",
+        data: "BAR",
+        meta: { from: MAIN_MESSAGE_TYPE, to: CONTENT_MESSAGE_TYPE },
+      });
+    });
+    describe("isBroadcastToContent", () => {
+      it("should return true if action is BroadcastToContent", () => {
+        assert.isTrue(
+          au.isBroadcastToContent(ac.BroadcastToContent({ type: "FOO" }))
+        );
+      });
+      it("should return false if action is not BroadcastToContent", () => {
+        assert.isFalse(au.isBroadcastToContent({ type: "FOO" }));
+        assert.isFalse(
+          au.isBroadcastToContent(
+            ac.AlsoToOneContent({ type: "FOO" }, "foo123")
+          )
+        );
+      });
+    });
+  });
+  describe("AlsoToPreloaded", () => {
+    it("should create the right action", () => {
+      const action = { type: "FOO", data: "BAR" };
+      const newAction = ac.AlsoToPreloaded(action);
+      assert.deepEqual(newAction, {
+        type: "FOO",
+        data: "BAR",
+        meta: { from: MAIN_MESSAGE_TYPE, to: PRELOAD_MESSAGE_TYPE },
+      });
+    });
+  });
+  describe("isSendToPreloaded", () => {
+    it("should return true if action is AlsoToPreloaded", () => {
+      assert.isTrue(au.isSendToPreloaded(ac.AlsoToPreloaded({ type: "FOO" })));
+    });
+    it("should return false if action is not AlsoToPreloaded", () => {
+      assert.isFalse(au.isSendToPreloaded({ type: "FOO" }));
+      assert.isFalse(
+        au.isSendToPreloaded(ac.BroadcastToContent({ type: "FOO" }))
+      );
+    });
+  });
+  describe("UserEvent", () => {
+    it("should include the given data", () => {
+      const data = { action: "foo" };
+      assert.equal(ac.UserEvent(data).data, data);
+    });
+    it("should wrap with AlsoToMain", () => {
+      const action = ac.UserEvent({ action: "foo" });
+      assert.isTrue(au.isSendToMain(action), "isSendToMain");
+    });
+  });
+  describe("ASRouterUserEvent", () => {
+    it("should include the given data", () => {
+      const data = { action: "foo" };
+      assert.equal(ac.ASRouterUserEvent(data).data, data);
+    });
+    it("should wrap with AlsoToMain", () => {
+      const action = ac.ASRouterUserEvent({ action: "foo" });
+      assert.isTrue(au.isSendToMain(action), "isSendToMain");
+    });
+  });
+  describe("ImpressionStats", () => {
+    it("should include the right data", () => {
+      const data = { action: "foo" };
+      assert.equal(ac.ImpressionStats(data).data, data);
+    });
+    it("should wrap with AlsoToMain if in UI code", () => {
+      assert.isTrue(
+        au.isSendToMain(ac.ImpressionStats({ action: "foo" })),
+        "isSendToMain"
+      );
+    });
+    it("should not wrap with AlsoToMain if not in UI code", () => {
+      const action = ac.ImpressionStats({ action: "foo" }, BACKGROUND_PROCESS);
+      assert.isFalse(au.isSendToMain(action), "isSendToMain");
+    });
+  });
+  describe("WebExtEvent", () => {
+    it("should set the provided type", () => {
+      const action = ac.WebExtEvent(at.WEBEXT_CLICK, {
+        source: "MyExtension",
+        url: "foo.com",
+      });
+      assert.equal(action.type, at.WEBEXT_CLICK);
+    });
+    it("should set the provided data", () => {
+      const data = { source: "MyExtension", url: "foo.com" };
+      const action = ac.WebExtEvent(at.WEBEXT_CLICK, data);
+      assert.equal(action.data, data);
+    });
+    it("should throw if the 'source' property is missing", () => {
+      assert.throws(() => {
+        ac.WebExtEvent(at.WEBEXT_CLICK, {});
+      });
+    });
+  });
+});
+
+describe("ActionUtils", () => {
+  describe("getPortIdOfSender", () => {
+    it("should return the PortID from a AlsoToMain action", () => {
+      const portID = "foo123";
+      const result = au.getPortIdOfSender(
+        ac.AlsoToMain({ type: "FOO" }, portID)
+      );
+      assert.equal(result, portID);
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/common/Dedupe.test.js b/browser/components/newtab/test/unit/common/Dedupe.test.js
new file mode 100644
index 0000000000..1c85eafa50
--- /dev/null
+++ b/browser/components/newtab/test/unit/common/Dedupe.test.js
@@ -0,0 +1,38 @@
+import { Dedupe } from "common/Dedupe.sys.mjs";
+
+describe("Dedupe", () => {
+  let instance;
+  beforeEach(() => {
+    instance = new Dedupe();
+  });
+  describe("group", () => {
+    it("should remove duplicates inside the groups", () => {
+      const beforeItems = [
+        [1, 1, 1],
+        [2, 2, 2],
+        [3, 3, 3],
+      ];
+      const afterItems = [[1], [2], [3]];
+      assert.deepEqual(instance.group(...beforeItems), afterItems);
+    });
+    it("should remove duplicates between groups, favouring earlier groups", () => {
+      const beforeItems = [
+        [1, 2, 3],
+        [2, 3, 4],
+        [3, 4, 5],
+      ];
+      const afterItems = [[1, 2, 3], [4], [5]];
+      assert.deepEqual(instance.group(...beforeItems), afterItems);
+    });
+    it("should remove duplicates from groups of objects", () => {
+      instance = new Dedupe(item => item.id);
+      const beforeItems = [
+        [{ id: 1 }, { id: 1 }, { id: 2 }],
+        [{ id: 1 }, { id: 3 }, { id: 2 }],
+        [{ id: 1 }, { id: 2 }, { id: 5 }],
+      ];
+      const afterItems = [[{ id: 1 }, { id: 2 }], [{ id: 3 }], [{ id: 5 }]];
+      assert.deepEqual(instance.group(...beforeItems), afterItems);
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/common/Reducers.test.js b/browser/components/newtab/test/unit/common/Reducers.test.js
new file mode 100644
index 0000000000..7343fc6224
--- /dev/null
+++ b/browser/components/newtab/test/unit/common/Reducers.test.js
@@ -0,0 +1,1525 @@
+import { INITIAL_STATE, insertPinned, reducers } from "common/Reducers.sys.mjs";
+const {
+  TopSites,
+  App,
+  Prefs,
+  Dialog,
+  Sections,
+  Pocket,
+  Personalization,
+  DiscoveryStream,
+  Search,
+  ASRouter,
+} = reducers;
+import { actionTypes as at } from "common/Actions.sys.mjs";
+
+describe("Reducers", () => {
+  describe("App", () => {
+    it("should return the initial state", () => {
+      const nextState = App(undefined, { type: "FOO" });
+      assert.equal(nextState, INITIAL_STATE.App);
+    });
+    it("should set initialized to true on INIT", () => {
+      const nextState = App(undefined, { type: "INIT" });
+
+      assert.propertyVal(nextState, "initialized", true);
+    });
+  });
+  describe("TopSites", () => {
+    it("should return the initial state", () => {
+      const nextState = TopSites(undefined, { type: "FOO" });
+      assert.equal(nextState, INITIAL_STATE.TopSites);
+    });
+    it("should add top sites on TOP_SITES_UPDATED", () => {
+      const newRows = [{ url: "foo.com" }, { url: "bar.com" }];
+      const nextState = TopSites(undefined, {
+        type: at.TOP_SITES_UPDATED,
+        data: { links: newRows },
+      });
+      assert.equal(nextState.rows, newRows);
+    });
+    it("should not update state for empty action.data on TOP_SITES_UPDATED", () => {
+      const nextState = TopSites(undefined, { type: at.TOP_SITES_UPDATED });
+      assert.equal(nextState, INITIAL_STATE.TopSites);
+    });
+    it("should initialize prefs on TOP_SITES_UPDATED", () => {
+      const nextState = TopSites(undefined, {
+        type: at.TOP_SITES_UPDATED,
+        data: { links: [], pref: "foo" },
+      });
+
+      assert.equal(nextState.pref, "foo");
+    });
+    it("should pass prevState.prefs if not present in TOP_SITES_UPDATED", () => {
+      const nextState = TopSites(
+        { prefs: "foo" },
+        { type: at.TOP_SITES_UPDATED, data: { links: [] } }
+      );
+
+      assert.equal(nextState.prefs, "foo");
+    });
+    it("should set editForm.site to action.data on TOP_SITES_EDIT", () => {
+      const data = { index: 7 };
+      const nextState = TopSites(undefined, { type: at.TOP_SITES_EDIT, data });
+      assert.equal(nextState.editForm.index, data.index);
+    });
+    it("should set editForm to null on TOP_SITES_CANCEL_EDIT", () => {
+      const nextState = TopSites(undefined, { type: at.TOP_SITES_CANCEL_EDIT });
+      assert.isNull(nextState.editForm);
+    });
+    it("should preserve the editForm.index", () => {
+      const actionTypes = [
+        at.PREVIEW_RESPONSE,
+        at.PREVIEW_REQUEST,
+        at.PREVIEW_REQUEST_CANCEL,
+      ];
+      actionTypes.forEach(type => {
+        const oldState = { editForm: { index: 0, previewUrl: "foo" } };
+        const action = { type, data: { url: "foo" } };
+        const nextState = TopSites(oldState, action);
+        assert.equal(nextState.editForm.index, 0);
+      });
+    });
+    it("should set previewResponse on PREVIEW_RESPONSE", () => {
+      const oldState = { editForm: { previewUrl: "url" } };
+      const action = {
+        type: at.PREVIEW_RESPONSE,
+        data: { preview: "data:123", url: "url" },
+      };
+      const nextState = TopSites(oldState, action);
+      assert.propertyVal(nextState.editForm, "previewResponse", "data:123");
+    });
+    it("should return previous state if action url does not match expected", () => {
+      const oldState = { editForm: { previewUrl: "foo" } };
+      const action = { type: at.PREVIEW_RESPONSE, data: { url: "bar" } };
+      const nextState = TopSites(oldState, action);
+      assert.equal(nextState, oldState);
+    });
+    it("should return previous state if editForm is not set", () => {
+      const actionTypes = [
+        at.PREVIEW_RESPONSE,
+        at.PREVIEW_REQUEST,
+        at.PREVIEW_REQUEST_CANCEL,
+      ];
+      actionTypes.forEach(type => {
+        const oldState = { editForm: null };
+        const action = { type, data: { url: "bar" } };
+        const nextState = TopSites(oldState, action);
+        assert.equal(nextState, oldState, type);
+      });
+    });
+    it("should set previewResponse to null on PREVIEW_REQUEST", () => {
+      const oldState = { editForm: { previewResponse: "foo" } };
+      const action = { type: at.PREVIEW_REQUEST, data: {} };
+      const nextState = TopSites(oldState, action);
+      assert.propertyVal(nextState.editForm, "previewResponse", null);
+    });
+    it("should set previewUrl on PREVIEW_REQUEST", () => {
+      const oldState = { editForm: {} };
+      const action = { type: at.PREVIEW_REQUEST, data: { url: "bar" } };
+      const nextState = TopSites(oldState, action);
+      assert.propertyVal(nextState.editForm, "previewUrl", "bar");
+    });
+    it("should add screenshots for SCREENSHOT_UPDATED", () => {
+      const oldState = { rows: [{ url: "foo.com" }, { url: "bar.com" }] };
+      const action = {
+        type: at.SCREENSHOT_UPDATED,
+        data: { url: "bar.com", screenshot: "data:123" },
+      };
+      const nextState = TopSites(oldState, action);
+      assert.deepEqual(nextState.rows, [
+        { url: "foo.com" },
+        { url: "bar.com", screenshot: "data:123" },
+      ]);
+    });
+    it("should not modify rows if nothing matches the url for SCREENSHOT_UPDATED", () => {
+      const oldState = { rows: [{ url: "foo.com" }, { url: "bar.com" }] };
+      const action = {
+        type: at.SCREENSHOT_UPDATED,
+        data: { url: "baz.com", screenshot: "data:123" },
+      };
+      const nextState = TopSites(oldState, action);
+      assert.deepEqual(nextState, oldState);
+    });
+    it("should bookmark an item on PLACES_BOOKMARK_ADDED", () => {
+      const oldState = { rows: [{ url: "foo.com" }, { url: "bar.com" }] };
+      const action = {
+        type: at.PLACES_BOOKMARK_ADDED,
+        data: {
+          url: "bar.com",
+          bookmarkGuid: "bookmark123",
+          bookmarkTitle: "Title for bar.com",
+          dateAdded: 1234567,
+        },
+      };
+      const nextState = TopSites(oldState, action);
+      const [, newRow] = nextState.rows;
+      // new row has bookmark data
+      assert.equal(newRow.url, action.data.url);
+      assert.equal(newRow.bookmarkGuid, action.data.bookmarkGuid);
+      assert.equal(newRow.bookmarkTitle, action.data.bookmarkTitle);
+      assert.equal(newRow.bookmarkDateCreated, action.data.dateAdded);
+
+      // old row is unchanged
+      assert.equal(nextState.rows[0], oldState.rows[0]);
+    });
+    it("should not update state for empty action.data on PLACES_BOOKMARK_ADDED", () => {
+      const nextState = TopSites(undefined, { type: at.PLACES_BOOKMARK_ADDED });
+      assert.equal(nextState, INITIAL_STATE.TopSites);
+    });
+    it("should remove a bookmark on PLACES_BOOKMARKS_REMOVED", () => {
+      const oldState = {
+        rows: [
+          { url: "foo.com" },
+          {
+            url: "bar.com",
+            bookmarkGuid: "bookmark123",
+            bookmarkTitle: "Title for bar.com",
+            dateAdded: 123456,
+          },
+        ],
+      };
+      const action = {
+        type: at.PLACES_BOOKMARKS_REMOVED,
+        data: { urls: ["bar.com"] },
+      };
+      const nextState = TopSites(oldState, action);
+      const [, newRow] = nextState.rows;
+      // new row no longer has bookmark data
+      assert.equal(newRow.url, oldState.rows[1].url);
+      assert.isUndefined(newRow.bookmarkGuid);
+      assert.isUndefined(newRow.bookmarkTitle);
+      assert.isUndefined(newRow.bookmarkDateCreated);
+
+      // old row is unchanged
+      assert.deepEqual(nextState.rows[0], oldState.rows[0]);
+    });
+    it("should not update state for empty action.data on PLACES_BOOKMARKS_REMOVED", () => {
+      const nextState = TopSites(undefined, {
+        type: at.PLACES_BOOKMARKS_REMOVED,
+      });
+      assert.equal(nextState, INITIAL_STATE.TopSites);
+    });
+    it("should update prefs on TOP_SITES_PREFS_UPDATED", () => {
+      const state = TopSites(
+        {},
+        { type: at.TOP_SITES_PREFS_UPDATED, data: { pref: "foo" } }
+      );
+
+      assert.equal(state.pref, "foo");
+    });
+    it("should not update state for empty action.data on PLACES_LINKS_DELETED", () => {
+      const nextState = TopSites(undefined, { type: at.PLACES_LINKS_DELETED });
+      assert.equal(nextState, INITIAL_STATE.TopSites);
+    });
+    it("should remove the site on PLACES_LINKS_DELETED", () => {
+      const oldState = { rows: [{ url: "foo.com" }, { url: "bar.com" }] };
+      const deleteAction = {
+        type: at.PLACES_LINKS_DELETED,
+        data: { urls: ["foo.com"] },
+      };
+      const nextState = TopSites(oldState, deleteAction);
+      assert.deepEqual(nextState.rows, [{ url: "bar.com" }]);
+    });
+    it("should set showSearchShortcutsForm to true on TOP_SITES_OPEN_SEARCH_SHORTCUTS_MODAL", () => {
+      const data = { index: 7 };
+      const nextState = TopSites(undefined, {
+        type: at.TOP_SITES_OPEN_SEARCH_SHORTCUTS_MODAL,
+        data,
+      });
+      assert.isTrue(nextState.showSearchShortcutsForm);
+    });
+    it("should set showSearchShortcutsForm to false on TOP_SITES_CLOSE_SEARCH_SHORTCUTS_MODAL", () => {
+      const nextState = TopSites(undefined, {
+        type: at.TOP_SITES_CLOSE_SEARCH_SHORTCUTS_MODAL,
+      });
+      assert.isFalse(nextState.showSearchShortcutsForm);
+    });
+    it("should update searchShortcuts on UPDATE_SEARCH_SHORTCUTS", () => {
+      const shortcuts = [
+        {
+          keyword: "@google",
+          shortURL: "google",
+          url: "https://google.com",
+          searchIdentifier: /^google/,
+        },
+        {
+          keyword: "@baidu",
+          shortURL: "baidu",
+          url: "https://baidu.com",
+          searchIdentifier: /^baidu/,
+        },
+      ];
+      const nextState = TopSites(undefined, {
+        type: at.UPDATE_SEARCH_SHORTCUTS,
+        data: { searchShortcuts: shortcuts },
+      });
+      assert.deepEqual(shortcuts, nextState.searchShortcuts);
+    });
+    it("should set sov positions and state", () => {
+      const positions = [
+        { position: 0, assignedPartner: "amp" },
+        { position: 1, assignedPartner: "moz-sales" },
+      ];
+      const nextState = TopSites(undefined, {
+        type: at.SOV_UPDATED,
+        data: { ready: true, positions },
+      });
+      assert.equal(nextState.sov.ready, true);
+      assert.equal(nextState.sov.positions, positions);
+    });
+  });
+  describe("Prefs", () => {
+    function prevState(custom = {}) {
+      return Object.assign({}, INITIAL_STATE.Prefs, custom);
+    }
+    it("should have the correct initial state", () => {
+      const state = Prefs(undefined, {});
+      assert.deepEqual(state, INITIAL_STATE.Prefs);
+    });
+    describe("PREFS_INITIAL_VALUES", () => {
+      it("should return a new object", () => {
+        const state = Prefs(undefined, {
+          type: at.PREFS_INITIAL_VALUES,
+          data: {},
+        });
+        assert.notEqual(
+          INITIAL_STATE.Prefs,
+          state,
+          "should not modify INITIAL_STATE"
+        );
+      });
+      it("should set initalized to true", () => {
+        const state = Prefs(undefined, {
+          type: at.PREFS_INITIAL_VALUES,
+          data: {},
+        });
+        assert.isTrue(state.initialized);
+      });
+      it("should set .values", () => {
+        const newValues = { foo: 1, bar: 2 };
+        const state = Prefs(undefined, {
+          type: at.PREFS_INITIAL_VALUES,
+          data: newValues,
+        });
+        assert.equal(state.values, newValues);
+      });
+    });
+    describe("PREF_CHANGED", () => {
+      it("should return a new Prefs object", () => {
+        const state = Prefs(undefined, {
+          type: at.PREF_CHANGED,
+          data: { name: "foo", value: 2 },
+        });
+        assert.notEqual(
+          INITIAL_STATE.Prefs,
+          state,
+          "should not modify INITIAL_STATE"
+        );
+      });
+      it("should set the changed pref", () => {
+        const state = Prefs(prevState({ foo: 1 }), {
+          type: at.PREF_CHANGED,
+          data: { name: "foo", value: 2 },
+        });
+        assert.equal(state.values.foo, 2);
+      });
+      it("should return a new .pref object instead of mutating", () => {
+        const oldState = prevState({ foo: 1 });
+        const state = Prefs(oldState, {
+          type: at.PREF_CHANGED,
+          data: { name: "foo", value: 2 },
+        });
+        assert.notEqual(oldState.values, state.values);
+      });
+    });
+  });
+  describe("Dialog", () => {
+    it("should return INITIAL_STATE by default", () => {
+      assert.equal(
+        INITIAL_STATE.Dialog,
+        Dialog(undefined, { type: "non_existent" })
+      );
+    });
+    it("should toggle visible to true on DIALOG_OPEN", () => {
+      const action = { type: at.DIALOG_OPEN };
+      const nextState = Dialog(INITIAL_STATE.Dialog, action);
+      assert.isTrue(nextState.visible);
+    });
+    it("should pass url data on DIALOG_OPEN", () => {
+      const action = { type: at.DIALOG_OPEN, data: "some url" };
+      const nextState = Dialog(INITIAL_STATE.Dialog, action);
+      assert.equal(nextState.data, action.data);
+    });
+    it("should toggle visible to false on DIALOG_CANCEL", () => {
+      const action = { type: at.DIALOG_CANCEL, data: "some url" };
+      const nextState = Dialog(INITIAL_STATE.Dialog, action);
+      assert.isFalse(nextState.visible);
+    });
+    it("should return inital state on DELETE_HISTORY_URL", () => {
+      const action = { type: at.DELETE_HISTORY_URL };
+      const nextState = Dialog(INITIAL_STATE.Dialog, action);
+
+      assert.deepEqual(INITIAL_STATE.Dialog, nextState);
+    });
+  });
+  describe("Sections", () => {
+    let oldState;
+
+    beforeEach(() => {
+      oldState = new Array(5).fill(null).map((v, i) => ({
+        id: `foo_bar_${i}`,
+        title: `Foo Bar ${i}`,
+        initialized: false,
+        rows: [
+          { url: "www.foo.bar", pocket_id: 123 },
+          { url: "www.other.url" },
+        ],
+        order: i,
+        type: "history",
+      }));
+    });
+
+    it("should return INITIAL_STATE by default", () => {
+      assert.equal(
+        INITIAL_STATE.Sections,
+        Sections(undefined, { type: "non_existent" })
+      );
+    });
+    it("should remove the correct section on SECTION_DEREGISTER", () => {
+      const newState = Sections(oldState, {
+        type: at.SECTION_DEREGISTER,
+        data: "foo_bar_2",
+      });
+      assert.lengthOf(newState, 4);
+      const expectedNewState = oldState.splice(2, 1) && oldState;
+      assert.deepEqual(newState, expectedNewState);
+    });
+    it("should add a section on SECTION_REGISTER if it doesn't already exist", () => {
+      const action = {
+        type: at.SECTION_REGISTER,
+        data: { id: "foo_bar_5", title: "Foo Bar 5" },
+      };
+      const newState = Sections(oldState, action);
+      assert.lengthOf(newState, 6);
+      const insertedSection = newState.find(
+        section => section.id === "foo_bar_5"
+      );
+      assert.propertyVal(insertedSection, "title", action.data.title);
+    });
+    it("should set newSection.rows === [] if no rows are provided on SECTION_REGISTER", () => {
+      const action = {
+        type: at.SECTION_REGISTER,
+        data: { id: "foo_bar_5", title: "Foo Bar 5" },
+      };
+      const newState = Sections(oldState, action);
+      const insertedSection = newState.find(
+        section => section.id === "foo_bar_5"
+      );
+      assert.deepEqual(insertedSection.rows, []);
+    });
+    it("should update a section on SECTION_REGISTER if it already exists", () => {
+      const NEW_TITLE = "New Title";
+      const action = {
+        type: at.SECTION_REGISTER,
+        data: { id: "foo_bar_2", title: NEW_TITLE },
+      };
+      const newState = Sections(oldState, action);
+      assert.lengthOf(newState, 5);
+      const updatedSection = newState.find(
+        section => section.id === "foo_bar_2"
+      );
+      assert.ok(updatedSection && updatedSection.title === NEW_TITLE);
+    });
+    it("should set initialized to false on SECTION_REGISTER if there are no rows", () => {
+      const NEW_TITLE = "New Title";
+      const action = {
+        type: at.SECTION_REGISTER,
+        data: { id: "bloop", title: NEW_TITLE },
+      };
+      const newState = Sections(oldState, action);
+      const updatedSection = newState.find(section => section.id === "bloop");
+      assert.propertyVal(updatedSection, "initialized", false);
+    });
+    it("should set initialized to true on SECTION_REGISTER if there are rows", () => {
+      const NEW_TITLE = "New Title";
+      const action = {
+        type: at.SECTION_REGISTER,
+        data: { id: "bloop", title: NEW_TITLE, rows: [{}, {}] },
+      };
+      const newState = Sections(oldState, action);
+      const updatedSection = newState.find(section => section.id === "bloop");
+      assert.propertyVal(updatedSection, "initialized", true);
+    });
+    it("should have no effect on SECTION_UPDATE if the id doesn't exist", () => {
+      const action = {
+        type: at.SECTION_UPDATE,
+        data: { id: "fake_id", data: "fake_data" },
+      };
+      const newState = Sections(oldState, action);
+      assert.deepEqual(oldState, newState);
+    });
+    it("should update the section with the correct data on SECTION_UPDATE", () => {
+      const FAKE_DATA = { rows: ["some", "fake", "data"], foo: "bar" };
+      const action = {
+        type: at.SECTION_UPDATE,
+        data: Object.assign(FAKE_DATA, { id: "foo_bar_2" }),
+      };
+      const newState = Sections(oldState, action);
+      const updatedSection = newState.find(
+        section => section.id === "foo_bar_2"
+      );
+      assert.include(updatedSection, FAKE_DATA);
+    });
+    it("should set initialized to true on SECTION_UPDATE if rows is defined on action.data", () => {
+      const data = { rows: [], id: "foo_bar_2" };
+      const action = { type: at.SECTION_UPDATE, data };
+      const newState = Sections(oldState, action);
+      const updatedSection = newState.find(
+        section => section.id === "foo_bar_2"
+      );
+      assert.propertyVal(updatedSection, "initialized", true);
+    });
+    it("should retain pinned cards on SECTION_UPDATE", () => {
+      const ROW = { id: "row" };
+      let newState = Sections(oldState, {
+        type: at.SECTION_UPDATE,
+        data: Object.assign({ rows: [ROW] }, { id: "foo_bar_2" }),
+      });
+      let updatedSection = newState.find(section => section.id === "foo_bar_2");
+      assert.deepEqual(updatedSection.rows, [ROW]);
+
+      const PINNED_ROW = { id: "pinned", pinned: true, guid: "pinned" };
+      newState = Sections(newState, {
+        type: at.SECTION_UPDATE,
+        data: Object.assign({ rows: [PINNED_ROW] }, { id: "foo_bar_2" }),
+      });
+      updatedSection = newState.find(section => section.id === "foo_bar_2");
+      assert.deepEqual(updatedSection.rows, [PINNED_ROW]);
+
+      // Updating the section again should not duplicate pinned cards
+      newState = Sections(newState, {
+        type: at.SECTION_UPDATE,
+        data: Object.assign({ rows: [PINNED_ROW] }, { id: "foo_bar_2" }),
+      });
+      updatedSection = newState.find(section => section.id === "foo_bar_2");
+      assert.deepEqual(updatedSection.rows, [PINNED_ROW]);
+
+      // Updating the section should retain pinned card at its index
+      newState = Sections(newState, {
+        type: at.SECTION_UPDATE,
+        data: Object.assign({ rows: [ROW] }, { id: "foo_bar_2" }),
+      });
+      updatedSection = newState.find(section => section.id === "foo_bar_2");
+      assert.deepEqual(updatedSection.rows, [PINNED_ROW, ROW]);
+
+      // Clearing/Resetting the section should clear pinned cards
+      newState = Sections(newState, {
+        type: at.SECTION_UPDATE,
+        data: Object.assign({ rows: [] }, { id: "foo_bar_2" }),
+      });
+      updatedSection = newState.find(section => section.id === "foo_bar_2");
+      assert.deepEqual(updatedSection.rows, []);
+    });
+    it("should have no effect on SECTION_UPDATE_CARD if the id or url doesn't exist", () => {
+      const noIdAction = {
+        type: at.SECTION_UPDATE_CARD,
+        data: {
+          id: "non-existent",
+          url: "www.foo.bar",
+          options: { title: "New title" },
+        },
+      };
+      const noIdState = Sections(oldState, noIdAction);
+      const noUrlAction = {
+        type: at.SECTION_UPDATE_CARD,
+        data: {
+          id: "foo_bar_2",
+          url: "www.non-existent.url",
+          options: { title: "New title" },
+        },
+      };
+      const noUrlState = Sections(oldState, noUrlAction);
+      assert.deepEqual(noIdState, oldState);
+      assert.deepEqual(noUrlState, oldState);
+    });
+    it("should update the card with the correct data on SECTION_UPDATE_CARD", () => {
+      const action = {
+        type: at.SECTION_UPDATE_CARD,
+        data: {
+          id: "foo_bar_2",
+          url: "www.other.url",
+          options: { title: "Fake new title" },
+        },
+      };
+      const newState = Sections(oldState, action);
+      const updatedSection = newState.find(
+        section => section.id === "foo_bar_2"
+      );
+      const updatedCard = updatedSection.rows.find(
+        card => card.url === "www.other.url"
+      );
+      assert.propertyVal(updatedCard, "title", "Fake new title");
+    });
+    it("should only update the cards belonging to the right section on SECTION_UPDATE_CARD", () => {
+      const action = {
+        type: at.SECTION_UPDATE_CARD,
+        data: {
+          id: "foo_bar_2",
+          url: "www.other.url",
+          options: { title: "Fake new title" },
+        },
+      };
+      const newState = Sections(oldState, action);
+      newState.forEach((section, i) => {
+        if (section.id !== "foo_bar_2") {
+          assert.deepEqual(section, oldState[i]);
+        }
+      });
+    });
+    it("should allow action.data to set .initialized", () => {
+      const data = { rows: [], initialized: false, id: "foo_bar_2" };
+      const action = { type: at.SECTION_UPDATE, data };
+      const newState = Sections(oldState, action);
+      const updatedSection = newState.find(
+        section => section.id === "foo_bar_2"
+      );
+      assert.propertyVal(updatedSection, "initialized", false);
+    });
+    it("should dedupe based on dedupeConfigurations", () => {
+      const site = { url: "foo.com" };
+      const highlights = { rows: [site], id: "highlights" };
+      const topstories = { rows: [site], id: "topstories" };
+      const dedupeConfigurations = [
+        { id: "topstories", dedupeFrom: ["highlights"] },
+      ];
+      const action = { data: { dedupeConfigurations }, type: "SECTION_UPDATE" };
+      const state = [highlights, topstories];
+
+      const nextState = Sections(state, action);
+
+      assert.equal(nextState.find(s => s.id === "highlights").rows.length, 1);
+      assert.equal(nextState.find(s => s.id === "topstories").rows.length, 0);
+    });
+    it("should remove blocked and deleted urls from all rows in all sections", () => {
+      const blockAction = {
+        type: at.PLACES_LINK_BLOCKED,
+        data: { url: "www.foo.bar" },
+      };
+      const deleteAction = {
+        type: at.PLACES_LINKS_DELETED,
+        data: { urls: ["www.foo.bar"] },
+      };
+      const newBlockState = Sections(oldState, blockAction);
+      const newDeleteState = Sections(oldState, deleteAction);
+      newBlockState.concat(newDeleteState).forEach(section => {
+        assert.deepEqual(section.rows, [{ url: "www.other.url" }]);
+      });
+    });
+    it("should not update state for empty action.data on PLACES_LINK_BLOCKED", () => {
+      const nextState = Sections(undefined, { type: at.PLACES_LINK_BLOCKED });
+      assert.equal(nextState, INITIAL_STATE.Sections);
+    });
+    it("should not update state for empty action.data on PLACES_LINKS_DELETED", () => {
+      const nextState = Sections(undefined, { type: at.PLACES_LINKS_DELETED });
+      assert.equal(nextState, INITIAL_STATE.Sections);
+    });
+    it("should remove all removed pocket urls", () => {
+      const removeAction = {
+        type: at.DELETE_FROM_POCKET,
+        data: { pocket_id: 123 },
+      };
+      const newBlockState = Sections(oldState, removeAction);
+      newBlockState.forEach(section => {
+        assert.deepEqual(section.rows, [{ url: "www.other.url" }]);
+      });
+    });
+    it("should archive all archived pocket urls", () => {
+      const removeAction = {
+        type: at.ARCHIVE_FROM_POCKET,
+        data: { pocket_id: 123 },
+      };
+      const newBlockState = Sections(oldState, removeAction);
+      newBlockState.forEach(section => {
+        assert.deepEqual(section.rows, [{ url: "www.other.url" }]);
+      });
+    });
+    it("should not update state for empty action.data on PLACES_BOOKMARK_ADDED", () => {
+      const nextState = Sections(undefined, { type: at.PLACES_BOOKMARK_ADDED });
+      assert.equal(nextState, INITIAL_STATE.Sections);
+    });
+    it("should bookmark an item when PLACES_BOOKMARK_ADDED is received", () => {
+      const action = {
+        type: at.PLACES_BOOKMARK_ADDED,
+        data: {
+          url: "www.foo.bar",
+          bookmarkGuid: "bookmark123",
+          bookmarkTitle: "Title for bar.com",
+          dateAdded: 1234567,
+        },
+      };
+      const nextState = Sections(oldState, action);
+      // check a section to ensure the correct url was bookmarked
+      const [newRow, oldRow] = nextState[0].rows;
+
+      // new row has bookmark data
+      assert.equal(newRow.url, action.data.url);
+      assert.equal(newRow.type, "bookmark");
+      assert.equal(newRow.bookmarkGuid, action.data.bookmarkGuid);
+      assert.equal(newRow.bookmarkTitle, action.data.bookmarkTitle);
+      assert.equal(newRow.bookmarkDateCreated, action.data.dateAdded);
+
+      // old row is unchanged
+      assert.equal(oldRow, oldState[0].rows[1]);
+    });
+    it("should not update state for empty action.data on PLACES_BOOKMARKS_REMOVED", () => {
+      const nextState = Sections(undefined, {
+        type: at.PLACES_BOOKMARKS_REMOVED,
+      });
+      assert.equal(nextState, INITIAL_STATE.Sections);
+    });
+    it("should remove the bookmark when PLACES_BOOKMARKS_REMOVED is received", () => {
+      const action = {
+        type: at.PLACES_BOOKMARKS_REMOVED,
+        data: {
+          urls: ["www.foo.bar"],
+          bookmarkGuid: "bookmark123",
+        },
+      };
+      // add some bookmark data for the first url in rows
+      oldState.forEach(item => {
+        item.rows[0].bookmarkGuid = "bookmark123";
+        item.rows[0].bookmarkTitle = "Title for bar.com";
+        item.rows[0].bookmarkDateCreated = 1234567;
+        item.rows[0].type = "bookmark";
+      });
+      const nextState = Sections(oldState, action);
+      // check a section to ensure the correct bookmark was removed
+      const [newRow, oldRow] = nextState[0].rows;
+
+      // new row isn't a bookmark
+      assert.equal(newRow.url, action.data.urls[0]);
+      assert.equal(newRow.type, "history");
+      assert.isUndefined(newRow.bookmarkGuid);
+      assert.isUndefined(newRow.bookmarkTitle);
+      assert.isUndefined(newRow.bookmarkDateCreated);
+
+      // old row is unchanged
+      assert.equal(oldRow, oldState[0].rows[1]);
+    });
+    it("should not update state for empty action.data on PLACES_SAVED_TO_POCKET", () => {
+      const nextState = Sections(undefined, {
+        type: at.PLACES_SAVED_TO_POCKET,
+      });
+      assert.equal(nextState, INITIAL_STATE.Sections);
+    });
+    it("should add a pocked item on PLACES_SAVED_TO_POCKET", () => {
+      const action = {
+        type: at.PLACES_SAVED_TO_POCKET,
+        data: {
+          url: "www.foo.bar",
+          pocket_id: 1234,
+          title: "Title for bar.com",
+        },
+      };
+      const nextState = Sections(oldState, action);
+      // check a section to ensure the correct url was saved to pocket
+      const [newRow, oldRow] = nextState[0].rows;
+
+      // new row has pocket data
+      assert.equal(newRow.url, action.data.url);
+      assert.equal(newRow.type, "pocket");
+      assert.equal(newRow.pocket_id, action.data.pocket_id);
+      assert.equal(newRow.title, action.data.title);
+
+      // old row is unchanged
+      assert.equal(oldRow, oldState[0].rows[1]);
+    });
+  });
+  describe("#insertPinned", () => {
+    let links;
+
+    beforeEach(() => {
+      links = new Array(12).fill(null).map((v, i) => ({ url: `site${i}.com` }));
+    });
+
+    it("should place pinned links where they belong", () => {
+      const pinned = [
+        { url: "http://github.com/mozilla/activity-stream", title: "moz/a-s" },
+        { url: "http://example.com", title: "example" },
+      ];
+      const result = insertPinned(links, pinned);
+      for (let index of [0, 1]) {
+        assert.equal(result[index].url, pinned[index].url);
+        assert.ok(result[index].isPinned);
+        assert.equal(result[index].pinIndex, index);
+      }
+      assert.deepEqual(result.slice(2), links);
+    });
+    it("should handle empty slots in the pinned list", () => {
+      const pinned = [
+        null,
+        { url: "http://github.com/mozilla/activity-stream", title: "moz/a-s" },
+        null,
+        null,
+        { url: "http://example.com", title: "example" },
+      ];
+      const result = insertPinned(links, pinned);
+      for (let index of [1, 4]) {
+        assert.equal(result[index].url, pinned[index].url);
+        assert.ok(result[index].isPinned);
+        assert.equal(result[index].pinIndex, index);
+      }
+      result.splice(4, 1);
+      result.splice(1, 1);
+      assert.deepEqual(result, links);
+    });
+    it("should handle a pinned site past the end of the list of links", () => {
+      const pinned = [];
+      pinned[11] = {
+        url: "http://github.com/mozilla/activity-stream",
+        title: "moz/a-s",
+      };
+      const result = insertPinned([], pinned);
+      assert.equal(result[11].url, pinned[11].url);
+      assert.isTrue(result[11].isPinned);
+      assert.equal(result[11].pinIndex, 11);
+    });
+    it("should unpin previously pinned links no longer in the pinned list", () => {
+      const pinned = [];
+      links[2].isPinned = true;
+      links[2].pinIndex = 2;
+      const result = insertPinned(links, pinned);
+      assert.notProperty(result[2], "isPinned");
+      assert.notProperty(result[2], "pinIndex");
+    });
+    it("should handle a link present in both the links and pinned list", () => {
+      const pinned = [links[7]];
+      const result = insertPinned(links, pinned);
+      assert.equal(links.length, result.length);
+    });
+    it("should not modify the original data", () => {
+      const pinned = [{ url: "http://example.com" }];
+
+      insertPinned(links, pinned);
+
+      assert.equal(typeof pinned[0].isPinned, "undefined");
+    });
+  });
+  describe("Pocket", () => {
+    it("should return INITIAL_STATE by default", () => {
+      assert.equal(
+        Pocket(undefined, { type: "some_action" }),
+        INITIAL_STATE.Pocket
+      );
+    });
+    it("should set waitingForSpoc on a POCKET_WAITING_FOR_SPOC action", () => {
+      const state = Pocket(undefined, {
+        type: at.POCKET_WAITING_FOR_SPOC,
+        data: false,
+      });
+      assert.isFalse(state.waitingForSpoc);
+    });
+    it("should have undefined for initial isUserLoggedIn state", () => {
+      assert.isNull(Pocket(undefined, { type: "some_action" }).isUserLoggedIn);
+    });
+    it("should set isUserLoggedIn to false on a POCKET_LOGGED_IN with null", () => {
+      const state = Pocket(undefined, {
+        type: at.POCKET_LOGGED_IN,
+        data: null,
+      });
+      assert.isFalse(state.isUserLoggedIn);
+    });
+    it("should set isUserLoggedIn to false on a POCKET_LOGGED_IN with false", () => {
+      const state = Pocket(undefined, {
+        type: at.POCKET_LOGGED_IN,
+        data: false,
+      });
+      assert.isFalse(state.isUserLoggedIn);
+    });
+    it("should set isUserLoggedIn to true on a POCKET_LOGGED_IN with true", () => {
+      const state = Pocket(undefined, {
+        type: at.POCKET_LOGGED_IN,
+        data: true,
+      });
+      assert.isTrue(state.isUserLoggedIn);
+    });
+    it("should set pocketCta with correct object on a POCKET_CTA", () => {
+      const data = {
+        cta_button: "cta button",
+        cta_text: "cta text",
+        cta_url: "https://cta-url.com",
+        use_cta: true,
+      };
+      const state = Pocket(undefined, { type: at.POCKET_CTA, data });
+      assert.equal(state.pocketCta.ctaButton, data.cta_button);
+      assert.equal(state.pocketCta.ctaText, data.cta_text);
+      assert.equal(state.pocketCta.ctaUrl, data.cta_url);
+      assert.equal(state.pocketCta.useCta, data.use_cta);
+    });
+  });
+  describe("Personalization", () => {
+    it("should return INITIAL_STATE by default", () => {
+      assert.equal(
+        Personalization(undefined, { type: "some_action" }),
+        INITIAL_STATE.Personalization
+      );
+    });
+    it("should set lastUpdated with DISCOVERY_STREAM_PERSONALIZATION_LAST_UPDATED", () => {
+      const state = Personalization(undefined, {
+        type: at.DISCOVERY_STREAM_PERSONALIZATION_LAST_UPDATED,
+        data: {
+          lastUpdated: 123,
+        },
+      });
+      assert.equal(state.lastUpdated, 123);
+    });
+    it("should set initialized to true with DISCOVERY_STREAM_PERSONALIZATION_INIT", () => {
+      const state = Personalization(undefined, {
+        type: at.DISCOVERY_STREAM_PERSONALIZATION_INIT,
+      });
+      assert.equal(state.initialized, true);
+    });
+  });
+  describe("DiscoveryStream", () => {
+    it("should return INITIAL_STATE by default", () => {
+      assert.equal(
+        DiscoveryStream(undefined, { type: "some_action" }),
+        INITIAL_STATE.DiscoveryStream
+      );
+    });
+    it("should set isPrivacyInfoModalVisible to true with SHOW_PRIVACY_INFO", () => {
+      const state = DiscoveryStream(undefined, {
+        type: at.SHOW_PRIVACY_INFO,
+      });
+      assert.equal(state.isPrivacyInfoModalVisible, true);
+    });
+    it("should set isPrivacyInfoModalVisible to false with HIDE_PRIVACY_INFO", () => {
+      const state = DiscoveryStream(undefined, {
+        type: at.HIDE_PRIVACY_INFO,
+      });
+      assert.equal(state.isPrivacyInfoModalVisible, false);
+    });
+    it("should set layout data with DISCOVERY_STREAM_LAYOUT_UPDATE", () => {
+      const state = DiscoveryStream(undefined, {
+        type: at.DISCOVERY_STREAM_LAYOUT_UPDATE,
+        data: { layout: ["test"] },
+      });
+      assert.equal(state.layout[0], "test");
+    });
+    it("should reset layout data with DISCOVERY_STREAM_LAYOUT_RESET", () => {
+      const layoutData = { layout: ["test"], lastUpdated: 123 };
+      const feedsData = {
+        "https://foo.com/feed1": { lastUpdated: 123, data: [1, 2, 3] },
+      };
+      const spocsData = {
+        lastUpdated: 123,
+        spocs: [1, 2, 3],
+      };
+      let state = DiscoveryStream(undefined, {
+        type: at.DISCOVERY_STREAM_LAYOUT_UPDATE,
+        data: layoutData,
+      });
+      state = DiscoveryStream(state, {
+        type: at.DISCOVERY_STREAM_FEEDS_UPDATE,
+        data: feedsData,
+      });
+      state = DiscoveryStream(state, {
+        type: at.DISCOVERY_STREAM_SPOCS_UPDATE,
+        data: spocsData,
+      });
+      state = DiscoveryStream(state, {
+        type: at.DISCOVERY_STREAM_LAYOUT_RESET,
+      });
+
+      assert.deepEqual(state, INITIAL_STATE.DiscoveryStream);
+    });
+    it("should set config data with DISCOVERY_STREAM_CONFIG_CHANGE", () => {
+      const state = DiscoveryStream(undefined, {
+        type: at.DISCOVERY_STREAM_CONFIG_CHANGE,
+        data: { enabled: true },
+      });
+      assert.deepEqual(state.config, { enabled: true });
+    });
+    it("should set recentSavesEnabled with DISCOVERY_STREAM_PREFS_SETUP", () => {
+      const state = DiscoveryStream(undefined, {
+        type: at.DISCOVERY_STREAM_PREFS_SETUP,
+        data: { recentSavesEnabled: true },
+      });
+      assert.isTrue(state.recentSavesEnabled);
+    });
+    it("should set recentSavesData with DISCOVERY_STREAM_RECENT_SAVES", () => {
+      const state = DiscoveryStream(undefined, {
+        type: at.DISCOVERY_STREAM_RECENT_SAVES,
+        data: { recentSaves: [1, 2, 3] },
+      });
+      assert.deepEqual(state.recentSavesData, [1, 2, 3]);
+    });
+    it("should set isUserLoggedIn with DISCOVERY_STREAM_POCKET_STATE_SET", () => {
+      const state = DiscoveryStream(undefined, {
+        type: at.DISCOVERY_STREAM_POCKET_STATE_SET,
+        data: { isUserLoggedIn: true },
+      });
+      assert.isTrue(state.isUserLoggedIn);
+    });
+    it("should set feeds as loaded with DISCOVERY_STREAM_FEEDS_UPDATE", () => {
+      const state = DiscoveryStream(undefined, {
+        type: at.DISCOVERY_STREAM_FEEDS_UPDATE,
+      });
+      assert.isTrue(state.feeds.loaded);
+    });
+    it("should set spoc_endpoint with DISCOVERY_STREAM_SPOCS_ENDPOINT", () => {
+      const state = DiscoveryStream(undefined, {
+        type: at.DISCOVERY_STREAM_SPOCS_ENDPOINT,
+        data: { url: "foo.com" },
+      });
+      assert.equal(state.spocs.spocs_endpoint, "foo.com");
+    });
+    it("should use initial state with DISCOVERY_STREAM_SPOCS_PLACEMENTS", () => {
+      const state = DiscoveryStream(undefined, {
+        type: at.DISCOVERY_STREAM_SPOCS_PLACEMENTS,
+        data: {},
+      });
+      assert.deepEqual(state.spocs.placements, []);
+    });
+    it("should set placements with DISCOVERY_STREAM_SPOCS_PLACEMENTS", () => {
+      const state = DiscoveryStream(undefined, {
+        type: at.DISCOVERY_STREAM_SPOCS_PLACEMENTS,
+        data: {
+          placements: [1, 2, 3],
+        },
+      });
+      assert.deepEqual(state.spocs.placements, [1, 2, 3]);
+    });
+    it("should set spocs with DISCOVERY_STREAM_SPOCS_UPDATE", () => {
+      const data = {
+        lastUpdated: 123,
+        spocs: [1, 2, 3],
+      };
+      const state = DiscoveryStream(undefined, {
+        type: at.DISCOVERY_STREAM_SPOCS_UPDATE,
+        data,
+      });
+      assert.deepEqual(state.spocs, {
+        spocs_endpoint: "",
+        data: [1, 2, 3],
+        lastUpdated: 123,
+        loaded: true,
+        frequency_caps: [],
+        blocked: [],
+        placements: [],
+      });
+    });
+    it("should default to a single spoc placement", () => {
+      const deleteAction = {
+        type: at.DISCOVERY_STREAM_LINK_BLOCKED,
+        data: { url: "https://foo.com" },
+      };
+      const oldState = {
+        spocs: {
+          data: {
+            spocs: {
+              items: [
+                {
+                  url: "test-spoc.com",
+                },
+              ],
+            },
+          },
+          loaded: true,
+        },
+        feeds: {
+          data: {},
+          loaded: true,
+        },
+      };
+
+      const newState = DiscoveryStream(oldState, deleteAction);
+
+      assert.equal(newState.spocs.data.spocs.items.length, 1);
+    });
+    it("should handle no data from DISCOVERY_STREAM_SPOCS_UPDATE", () => {
+      const data = null;
+      const state = DiscoveryStream(undefined, {
+        type: at.DISCOVERY_STREAM_SPOCS_UPDATE,
+        data,
+      });
+      assert.deepEqual(state.spocs, INITIAL_STATE.DiscoveryStream.spocs);
+    });
+    it("should add blocked spocs to blocked array with DISCOVERY_STREAM_SPOC_BLOCKED", () => {
+      const firstState = DiscoveryStream(undefined, {
+        type: at.DISCOVERY_STREAM_SPOC_BLOCKED,
+        data: { url: "https://foo.com" },
+      });
+      const secondState = DiscoveryStream(firstState, {
+        type: at.DISCOVERY_STREAM_SPOC_BLOCKED,
+        data: { url: "https://bar.com" },
+      });
+      assert.deepEqual(firstState.spocs.blocked, ["https://foo.com"]);
+      assert.deepEqual(secondState.spocs.blocked, [
+        "https://foo.com",
+        "https://bar.com",
+      ]);
+    });
+    it("should not update state for empty action.data on DISCOVERY_STREAM_LINK_BLOCKED", () => {
+      const newState = DiscoveryStream(undefined, {
+        type: at.DISCOVERY_STREAM_LINK_BLOCKED,
+      });
+      assert.equal(newState, INITIAL_STATE.DiscoveryStream);
+    });
+    it("should not update state if feeds are not loaded", () => {
+      const deleteAction = {
+        type: at.DISCOVERY_STREAM_LINK_BLOCKED,
+        data: { url: "foo.com" },
+      };
+      const newState = DiscoveryStream(undefined, deleteAction);
+      assert.equal(newState, INITIAL_STATE.DiscoveryStream);
+    });
+    it("should not update state if spocs and feeds data is undefined", () => {
+      const deleteAction = {
+        type: at.DISCOVERY_STREAM_LINK_BLOCKED,
+        data: { url: "foo.com" },
+      };
+      const oldState = {
+        spocs: {
+          data: {},
+          loaded: true,
+          placements: [{ name: "spocs" }],
+        },
+        feeds: {
+          data: {},
+          loaded: true,
+        },
+      };
+      const newState = DiscoveryStream(oldState, deleteAction);
+      assert.deepEqual(newState, oldState);
+    });
+    it("should remove the site on DISCOVERY_STREAM_LINK_BLOCKED from spocs if feeds data is empty", () => {
+      const deleteAction = {
+        type: at.DISCOVERY_STREAM_LINK_BLOCKED,
+        data: { url: "https://foo.com" },
+      };
+      const oldState = {
+        spocs: {
+          data: {
+            spocs: {
+              items: [{ url: "https://foo.com" }, { url: "test-spoc.com" }],
+            },
+          },
+          loaded: true,
+          placements: [{ name: "spocs" }],
+        },
+        feeds: {
+          data: {},
+          loaded: true,
+        },
+      };
+      const newState = DiscoveryStream(oldState, deleteAction);
+      assert.deepEqual(newState.spocs.data.spocs.items, [
+        { url: "test-spoc.com" },
+      ]);
+    });
+    it("should remove the site on DISCOVERY_STREAM_LINK_BLOCKED from feeds if spocs data is empty", () => {
+      const deleteAction = {
+        type: at.DISCOVERY_STREAM_LINK_BLOCKED,
+        data: { url: "https://foo.com" },
+      };
+      const oldState = {
+        spocs: {
+          data: {},
+          loaded: true,
+          placements: [{ name: "spocs" }],
+        },
+        feeds: {
+          data: {
+            "https://foo.com/feed1": {
+              data: {
+                recommendations: [
+                  { url: "https://foo.com" },
+                  { url: "test.com" },
+                ],
+              },
+            },
+          },
+          loaded: true,
+        },
+      };
+      const newState = DiscoveryStream(oldState, deleteAction);
+      assert.deepEqual(
+        newState.feeds.data["https://foo.com/feed1"].data.recommendations,
+        [{ url: "test.com" }]
+      );
+    });
+    it("should remove the site on DISCOVERY_STREAM_LINK_BLOCKED from both feeds and spocs", () => {
+      const oldState = {
+        feeds: {
+          data: {
+            "https://foo.com/feed1": {
+              data: {
+                recommendations: [
+                  { url: "https://foo.com" },
+                  { url: "test.com" },
+                ],
+              },
+            },
+          },
+          loaded: true,
+        },
+        spocs: {
+          data: {
+            spocs: {
+              items: [{ url: "https://foo.com" }, { url: "test-spoc.com" }],
+            },
+          },
+          loaded: true,
+          placements: [{ name: "spocs" }],
+        },
+      };
+      const deleteAction = {
+        type: at.DISCOVERY_STREAM_LINK_BLOCKED,
+        data: { url: "https://foo.com" },
+      };
+      const newState = DiscoveryStream(oldState, deleteAction);
+      assert.deepEqual(newState.spocs.data.spocs.items, [
+        { url: "test-spoc.com" },
+      ]);
+      assert.deepEqual(
+        newState.feeds.data["https://foo.com/feed1"].data.recommendations,
+        [{ url: "test.com" }]
+      );
+    });
+    it("should not update state for empty action.data on PLACES_SAVED_TO_POCKET", () => {
+      const newState = DiscoveryStream(undefined, {
+        type: at.PLACES_SAVED_TO_POCKET,
+      });
+      assert.equal(newState, INITIAL_STATE.DiscoveryStream);
+    });
+    it("should add pocket_id on PLACES_SAVED_TO_POCKET in both feeds and spocs", () => {
+      const oldState = {
+        feeds: {
+          data: {
+            "https://foo.com/feed1": {
+              data: {
+                recommendations: [
+                  { url: "https://foo.com" },
+                  { url: "test.com" },
+                ],
+              },
+            },
+          },
+          loaded: true,
+        },
+        spocs: {
+          data: {
+            spocs: {
+              items: [{ url: "https://foo.com" }, { url: "test-spoc.com" }],
+            },
+          },
+          placements: [{ name: "spocs" }],
+          loaded: true,
+        },
+      };
+      const action = {
+        type: at.PLACES_SAVED_TO_POCKET,
+        data: {
+          url: "https://foo.com",
+          pocket_id: 1234,
+          open_url: "https://foo-1234",
+        },
+      };
+
+      const newState = DiscoveryStream(oldState, action);
+
+      assert.lengthOf(newState.spocs.data.spocs.items, 2);
+      assert.equal(
+        newState.spocs.data.spocs.items[0].pocket_id,
+        action.data.pocket_id
+      );
+      assert.equal(
+        newState.spocs.data.spocs.items[0].open_url,
+        action.data.open_url
+      );
+      assert.isUndefined(newState.spocs.data.spocs.items[1].pocket_id);
+
+      assert.lengthOf(
+        newState.feeds.data["https://foo.com/feed1"].data.recommendations,
+        2
+      );
+      assert.equal(
+        newState.feeds.data["https://foo.com/feed1"].data.recommendations[0]
+          .pocket_id,
+        action.data.pocket_id
+      );
+      assert.equal(
+        newState.feeds.data["https://foo.com/feed1"].data.recommendations[0]
+          .open_url,
+        action.data.open_url
+      );
+      assert.isUndefined(
+        newState.feeds.data["https://foo.com/feed1"].data.recommendations[1]
+          .pocket_id
+      );
+    });
+    it("should not update state for empty action.data on DELETE_FROM_POCKET", () => {
+      const newState = DiscoveryStream(undefined, {
+        type: at.DELETE_FROM_POCKET,
+      });
+      assert.equal(newState, INITIAL_STATE.DiscoveryStream);
+    });
+    it("should remove site on DELETE_FROM_POCKET in both feeds and spocs", () => {
+      const oldState = {
+        feeds: {
+          data: {
+            "https://foo.com/feed1": {
+              data: {
+                recommendations: [
+                  { url: "https://foo.com", pocket_id: 1234 },
+                  { url: "test.com" },
+                ],
+              },
+            },
+          },
+          loaded: true,
+        },
+        spocs: {
+          data: {
+            spocs: {
+              items: [
+                { url: "https://foo.com", pocket_id: 1234 },
+                { url: "test-spoc.com" },
+              ],
+            },
+          },
+          loaded: true,
+          placements: [{ name: "spocs" }],
+        },
+      };
+      const deleteAction = {
+        type: at.DELETE_FROM_POCKET,
+        data: {
+          pocket_id: 1234,
+        },
+      };
+
+      const newState = DiscoveryStream(oldState, deleteAction);
+      assert.deepEqual(newState.spocs.data.spocs.items, [
+        { url: "test-spoc.com" },
+      ]);
+      assert.deepEqual(
+        newState.feeds.data["https://foo.com/feed1"].data.recommendations,
+        [{ url: "test.com" }]
+      );
+    });
+    it("should remove site on ARCHIVE_FROM_POCKET in both feeds and spocs", () => {
+      const oldState = {
+        feeds: {
+          data: {
+            "https://foo.com/feed1": {
+              data: {
+                recommendations: [
+                  { url: "https://foo.com", pocket_id: 1234 },
+                  { url: "test.com" },
+                ],
+              },
+            },
+          },
+          loaded: true,
+        },
+        spocs: {
+          data: {
+            spocs: {
+              items: [
+                { url: "https://foo.com", pocket_id: 1234 },
+                { url: "test-spoc.com" },
+              ],
+            },
+          },
+          loaded: true,
+          placements: [{ name: "spocs" }],
+        },
+      };
+      const deleteAction = {
+        type: at.ARCHIVE_FROM_POCKET,
+        data: {
+          pocket_id: 1234,
+        },
+      };
+
+      const newState = DiscoveryStream(oldState, deleteAction);
+      assert.deepEqual(newState.spocs.data.spocs.items, [
+        { url: "test-spoc.com" },
+      ]);
+      assert.deepEqual(
+        newState.feeds.data["https://foo.com/feed1"].data.recommendations,
+        [{ url: "test.com" }]
+      );
+    });
+    it("should add boookmark details on PLACES_BOOKMARK_ADDED in both feeds and spocs", () => {
+      const oldState = {
+        feeds: {
+          data: {
+            "https://foo.com/feed1": {
+              data: {
+                recommendations: [
+                  { url: "https://foo.com" },
+                  { url: "test.com" },
+                ],
+              },
+            },
+          },
+          loaded: true,
+        },
+        spocs: {
+          data: {
+            spocs: {
+              items: [{ url: "https://foo.com" }, { url: "test-spoc.com" }],
+            },
+          },
+          loaded: true,
+          placements: [{ name: "spocs" }],
+        },
+      };
+      const bookmarkAction = {
+        type: at.PLACES_BOOKMARK_ADDED,
+        data: {
+          url: "https://foo.com",
+          bookmarkGuid: "bookmark123",
+          bookmarkTitle: "Title for bar.com",
+          dateAdded: 1234567,
+        },
+      };
+
+      const newState = DiscoveryStream(oldState, bookmarkAction);
+
+      assert.lengthOf(newState.spocs.data.spocs.items, 2);
+      assert.equal(
+        newState.spocs.data.spocs.items[0].bookmarkGuid,
+        bookmarkAction.data.bookmarkGuid
+      );
+      assert.equal(
+        newState.spocs.data.spocs.items[0].bookmarkTitle,
+        bookmarkAction.data.bookmarkTitle
+      );
+      assert.isUndefined(newState.spocs.data.spocs.items[1].bookmarkGuid);
+
+      assert.lengthOf(
+        newState.feeds.data["https://foo.com/feed1"].data.recommendations,
+        2
+      );
+      assert.equal(
+        newState.feeds.data["https://foo.com/feed1"].data.recommendations[0]
+          .bookmarkGuid,
+        bookmarkAction.data.bookmarkGuid
+      );
+      assert.equal(
+        newState.feeds.data["https://foo.com/feed1"].data.recommendations[0]
+          .bookmarkTitle,
+        bookmarkAction.data.bookmarkTitle
+      );
+      assert.isUndefined(
+        newState.feeds.data["https://foo.com/feed1"].data.recommendations[1]
+          .bookmarkGuid
+      );
+    });
+
+    it("should remove boookmark details on PLACES_BOOKMARKS_REMOVED in both feeds and spocs", () => {
+      const oldState = {
+        feeds: {
+          data: {
+            "https://foo.com/feed1": {
+              data: {
+                recommendations: [
+                  {
+                    url: "https://foo.com",
+                    bookmarkGuid: "bookmark123",
+                    bookmarkTitle: "Title for bar.com",
+                  },
+                  { url: "test.com" },
+                ],
+              },
+            },
+          },
+          loaded: true,
+        },
+        spocs: {
+          data: {
+            spocs: {
+              items: [
+                {
+                  url: "https://foo.com",
+                  bookmarkGuid: "bookmark123",
+                  bookmarkTitle: "Title for bar.com",
+                },
+                { url: "test-spoc.com" },
+              ],
+            },
+          },
+          loaded: true,
+          placements: [{ name: "spocs" }],
+        },
+      };
+      const action = {
+        type: at.PLACES_BOOKMARKS_REMOVED,
+        data: {
+          urls: ["https://foo.com"],
+        },
+      };
+
+      const newState = DiscoveryStream(oldState, action);
+
+      assert.lengthOf(newState.spocs.data.spocs.items, 2);
+      assert.isUndefined(newState.spocs.data.spocs.items[0].bookmarkGuid);
+      assert.isUndefined(newState.spocs.data.spocs.items[0].bookmarkTitle);
+
+      assert.lengthOf(
+        newState.feeds.data["https://foo.com/feed1"].data.recommendations,
+        2
+      );
+      assert.isUndefined(
+        newState.feeds.data["https://foo.com/feed1"].data.recommendations[0]
+          .bookmarkGuid
+      );
+      assert.isUndefined(
+        newState.feeds.data["https://foo.com/feed1"].data.recommendations[0]
+          .bookmarkTitle
+      );
+    });
+    describe("PREF_CHANGED", () => {
+      it("should set isCollectionDismissible", () => {
+        const state = DiscoveryStream(undefined, {
+          type: at.PREF_CHANGED,
+          data: {
+            name: "discoverystream.isCollectionDismissible",
+            value: true,
+          },
+        });
+        assert.equal(state.isCollectionDismissible, true);
+      });
+    });
+  });
+  describe("Search", () => {
+    it("should return INITIAL_STATE by default", () => {
+      assert.equal(
+        Search(undefined, { type: "some_action" }),
+        INITIAL_STATE.Search
+      );
+    });
+    it("should set disable to true on DISABLE_SEARCH", () => {
+      const nextState = Search(undefined, { type: "DISABLE_SEARCH" });
+      assert.propertyVal(nextState, "disable", true);
+    });
+    it("should set focus to true on FAKE_FOCUS_SEARCH", () => {
+      const nextState = Search(undefined, { type: "FAKE_FOCUS_SEARCH" });
+      assert.propertyVal(nextState, "fakeFocus", true);
+    });
+    it("should set focus and disable to false on SHOW_SEARCH", () => {
+      const nextState = Search(undefined, { type: "SHOW_SEARCH" });
+      assert.propertyVal(nextState, "fakeFocus", false);
+      assert.propertyVal(nextState, "disable", false);
+    });
+  });
+  it("should set initialized to true on AS_ROUTER_INITIALIZED", () => {
+    const nextState = ASRouter(undefined, { type: "AS_ROUTER_INITIALIZED" });
+    assert.propertyVal(nextState, "initialized", true);
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/Base.test.jsx b/browser/components/newtab/test/unit/content-src/components/Base.test.jsx
new file mode 100644
index 0000000000..c764348006
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/Base.test.jsx
@@ -0,0 +1,130 @@
+import {
+  _Base as Base,
+  BaseContent,
+  PrefsButton,
+} from "content-src/components/Base/Base";
+import { DiscoveryStreamAdmin } from "content-src/components/DiscoveryStreamAdmin/DiscoveryStreamAdmin";
+import { ErrorBoundary } from "content-src/components/ErrorBoundary/ErrorBoundary";
+import React from "react";
+import { Search } from "content-src/components/Search/Search";
+import { shallow } from "enzyme";
+import { actionCreators as ac } from "common/Actions.sys.mjs";
+
+describe("<Base>", () => {
+  let DEFAULT_PROPS = {
+    store: { getState: () => {} },
+    App: { initialized: true },
+    Prefs: { values: {} },
+    Sections: [],
+    DiscoveryStream: { config: { enabled: false } },
+    dispatch: () => {},
+    adminContent: {
+      message: {},
+    },
+  };
+
+  it("should render Base component", () => {
+    const wrapper = shallow(<Base {...DEFAULT_PROPS} />);
+    assert.ok(wrapper.exists());
+  });
+
+  it("should render the BaseContent component, passing through all props", () => {
+    const wrapper = shallow(<Base {...DEFAULT_PROPS} />);
+    const props = wrapper.find(BaseContent).props();
+    assert.deepEqual(
+      props,
+      DEFAULT_PROPS,
+      JSON.stringify([props, DEFAULT_PROPS], null, 3)
+    );
+  });
+
+  it("should render an ErrorBoundary with class base-content-fallback", () => {
+    const wrapper = shallow(<Base {...DEFAULT_PROPS} />);
+
+    assert.equal(
+      wrapper.find(ErrorBoundary).first().prop("className"),
+      "base-content-fallback"
+    );
+  });
+
+  it("should render an DiscoveryStreamAdmin if the devtools pref is true", () => {
+    const wrapper = shallow(
+      <Base
+        {...DEFAULT_PROPS}
+        Prefs={{ values: { "asrouter.devtoolsEnabled": true } }}
+      />
+    );
+    assert.lengthOf(wrapper.find(DiscoveryStreamAdmin), 1);
+  });
+
+  it("should not render an DiscoveryStreamAdmin if the devtools pref is false", () => {
+    const wrapper = shallow(
+      <Base
+        {...DEFAULT_PROPS}
+        Prefs={{ values: { "asrouter.devtoolsEnabled": false } }}
+      />
+    );
+    assert.lengthOf(wrapper.find(DiscoveryStreamAdmin), 0);
+  });
+});
+
+describe("<BaseContent>", () => {
+  let DEFAULT_PROPS = {
+    store: { getState: () => {} },
+    App: { initialized: true },
+    Prefs: { values: {} },
+    Sections: [],
+    DiscoveryStream: { config: { enabled: false } },
+    dispatch: () => {},
+  };
+
+  it("should render an ErrorBoundary with a Search child", () => {
+    const searchEnabledProps = Object.assign({}, DEFAULT_PROPS, {
+      Prefs: { values: { showSearch: true } },
+    });
+
+    const wrapper = shallow(<BaseContent {...searchEnabledProps} />);
+
+    assert.isTrue(wrapper.find(Search).parent().is(ErrorBoundary));
+  });
+
+  it("should dispatch a user event when the customize menu is opened or closed", () => {
+    const dispatch = sinon.stub();
+    const wrapper = shallow(
+      <BaseContent
+        {...DEFAULT_PROPS}
+        dispatch={dispatch}
+        App={{ customizeMenuVisible: true }}
+      />
+    );
+    wrapper.instance().openCustomizationMenu();
+    assert.calledWith(dispatch, { type: "SHOW_PERSONALIZE" });
+    assert.calledWith(dispatch, ac.UserEvent({ event: "SHOW_PERSONALIZE" }));
+    wrapper.instance().closeCustomizationMenu();
+    assert.calledWith(dispatch, { type: "HIDE_PERSONALIZE" });
+    assert.calledWith(dispatch, ac.UserEvent({ event: "HIDE_PERSONALIZE" }));
+  });
+
+  it("should render only search if no Sections are enabled", () => {
+    const onlySearchProps = Object.assign({}, DEFAULT_PROPS, {
+      Sections: [{ id: "highlights", enabled: false }],
+      Prefs: { values: { showSearch: true } },
+    });
+
+    const wrapper = shallow(<BaseContent {...onlySearchProps} />);
+    assert.lengthOf(wrapper.find(".only-search"), 1);
+  });
+});
+
+describe("<PrefsButton>", () => {
+  it("should render icon-settings if props.icon is empty", () => {
+    const wrapper = shallow(<PrefsButton icon="" />);
+
+    assert.isTrue(wrapper.find("button").hasClass("icon-settings"));
+  });
+  it("should render props.icon as a className", () => {
+    const wrapper = shallow(<PrefsButton icon="icon-happy" />);
+
+    assert.isTrue(wrapper.find("button").hasClass("icon-happy"));
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/Card.test.jsx b/browser/components/newtab/test/unit/content-src/components/Card.test.jsx
new file mode 100644
index 0000000000..5f07570b2e
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/Card.test.jsx
@@ -0,0 +1,510 @@
+import {
+  actionCreators as ac,
+  actionTypes as at,
+} from "common/Actions.sys.mjs";
+import {
+  _Card as Card,
+  PlaceholderCard,
+} from "content-src/components/Card/Card";
+import { combineReducers, createStore } from "redux";
+import { GlobalOverrider } from "test/unit/utils";
+import { INITIAL_STATE, reducers } from "common/Reducers.sys.mjs";
+import { cardContextTypes } from "content-src/components/Card/types";
+import { ContextMenuButton } from "content-src/components/ContextMenu/ContextMenuButton";
+import { LinkMenu } from "content-src/components/LinkMenu/LinkMenu";
+import { Provider } from "react-redux";
+import React from "react";
+import { shallow, mount } from "enzyme";
+
+let DEFAULT_PROPS = {
+  dispatch: sinon.stub(),
+  index: 0,
+  link: {
+    hostname: "foo",
+    title: "A title for foo",
+    url: "http://www.foo.com",
+    type: "history",
+    description: "A description for foo",
+    image: "http://www.foo.com/img.png",
+    guid: 1,
+  },
+  eventSource: "TOP_STORIES",
+  shouldSendImpressionStats: true,
+  contextMenuOptions: ["Separator"],
+};
+
+let DEFAULT_BLOB_IMAGE = {
+  path: "/testpath",
+  data: new Blob([0]),
+};
+
+function mountCardWithProps(props) {
+  const store = createStore(combineReducers(reducers), INITIAL_STATE);
+  return mount(
+    <Provider store={store}>
+      <Card {...props} />
+    </Provider>
+  );
+}
+
+describe("<Card>", () => {
+  let globals;
+  let wrapper;
+  beforeEach(() => {
+    globals = new GlobalOverrider();
+    wrapper = mountCardWithProps(DEFAULT_PROPS);
+  });
+  afterEach(() => {
+    DEFAULT_PROPS.dispatch.reset();
+    globals.restore();
+  });
+  it("should render a Card component", () => assert.ok(wrapper.exists()));
+  it("should add the right url", () => {
+    assert.propertyVal(
+      wrapper.find("a").props(),
+      "href",
+      DEFAULT_PROPS.link.url
+    );
+
+    // test that pocket cards get a special open_url href
+    const pocketLink = Object.assign({}, DEFAULT_PROPS.link, {
+      open_url: "getpocket.com/foo",
+      type: "pocket",
+    });
+    wrapper = mount(
+      <Card {...Object.assign({}, DEFAULT_PROPS, { link: pocketLink })} />
+    );
+    assert.propertyVal(wrapper.find("a").props(), "href", pocketLink.open_url);
+  });
+  it("should display a title", () =>
+    assert.equal(wrapper.find(".card-title").text(), DEFAULT_PROPS.link.title));
+  it("should display a description", () =>
+    assert.equal(
+      wrapper.find(".card-description").text(),
+      DEFAULT_PROPS.link.description
+    ));
+  it("should display a host name", () =>
+    assert.equal(wrapper.find(".card-host-name").text(), "foo"));
+  it("should have a link menu button", () =>
+    assert.ok(wrapper.find(".context-menu-button").exists()));
+  it("should render a link menu when button is clicked", () => {
+    const button = wrapper.find(".context-menu-button");
+    assert.equal(wrapper.find(LinkMenu).length, 0);
+    button.simulate("click", { preventDefault: () => {} });
+    assert.equal(wrapper.find(LinkMenu).length, 1);
+  });
+  it("should pass dispatch, source, onUpdate, site, options, and index to LinkMenu", () => {
+    wrapper
+      .find(".context-menu-button")
+      .simulate("click", { preventDefault: () => {} });
+    const { dispatch, source, onUpdate, site, options, index } = wrapper
+      .find(LinkMenu)
+      .props();
+    assert.equal(dispatch, DEFAULT_PROPS.dispatch);
+    assert.equal(source, DEFAULT_PROPS.eventSource);
+    assert.ok(onUpdate);
+    assert.equal(site, DEFAULT_PROPS.link);
+    assert.equal(options, DEFAULT_PROPS.contextMenuOptions);
+    assert.equal(index, DEFAULT_PROPS.index);
+  });
+  it("should pass through the correct menu options to LinkMenu if overridden by individual card", () => {
+    const link = Object.assign({}, DEFAULT_PROPS.link);
+    link.contextMenuOptions = ["CheckBookmark"];
+
+    wrapper = mountCardWithProps(Object.assign({}, DEFAULT_PROPS, { link }));
+    wrapper
+      .find(".context-menu-button")
+      .simulate("click", { preventDefault: () => {} });
+    const { options } = wrapper.find(LinkMenu).props();
+    assert.equal(options, link.contextMenuOptions);
+  });
+  it("should have a context based on type", () => {
+    wrapper = shallow(<Card {...DEFAULT_PROPS} />);
+    const context = wrapper.find(".card-context");
+    const { icon, fluentID } = cardContextTypes[DEFAULT_PROPS.link.type];
+    assert.isTrue(context.childAt(0).hasClass(`icon-${icon}`));
+    assert.isTrue(context.childAt(1).hasClass("card-context-label"));
+    assert.equal(context.childAt(1).prop("data-l10n-id"), fluentID);
+  });
+  it("should support setting custom context", () => {
+    const linkWithCustomContext = {
+      type: "history",
+      context: "Custom",
+      icon: "icon-url",
+    };
+
+    wrapper = shallow(
+      <Card
+        {...Object.assign({}, DEFAULT_PROPS, { link: linkWithCustomContext })}
+      />
+    );
+    const context = wrapper.find(".card-context");
+    const { icon } = cardContextTypes[DEFAULT_PROPS.link.type];
+    assert.isFalse(context.childAt(0).hasClass(`icon-${icon}`));
+    assert.equal(
+      context.childAt(0).props().style.backgroundImage,
+      "url('icon-url')"
+    );
+
+    assert.isTrue(context.childAt(1).hasClass("card-context-label"));
+    assert.equal(context.childAt(1).text(), linkWithCustomContext.context);
+  });
+  it("should parse args for fluent correctly", () => {
+    const title = '"fluent"';
+    const link = { ...DEFAULT_PROPS.link, title };
+
+    wrapper = mountCardWithProps({ ...DEFAULT_PROPS, link });
+    let button = wrapper.find(ContextMenuButton).find("button");
+
+    assert.equal(button.prop("data-l10n-args"), JSON.stringify({ title }));
+  });
+  it("should have .active class, on card-outer if context menu is open", () => {
+    const button = wrapper.find(ContextMenuButton);
+    assert.isFalse(
+      wrapper.find(".card-outer").hasClass("active"),
+      "does not have active class"
+    );
+    button.simulate("click", { preventDefault: () => {} });
+    assert.isTrue(
+      wrapper.find(".card-outer").hasClass("active"),
+      "has active class"
+    );
+  });
+  it("should send OPEN_DOWNLOAD_FILE if we clicked on a download", () => {
+    const downloadLink = {
+      type: "download",
+      url: "download.mov",
+    };
+    wrapper = mountCardWithProps(
+      Object.assign({}, DEFAULT_PROPS, { link: downloadLink })
+    );
+    const card = wrapper.find(".card");
+    card.simulate("click", { preventDefault: () => {} });
+    assert.calledThrice(DEFAULT_PROPS.dispatch);
+
+    assert.equal(
+      DEFAULT_PROPS.dispatch.firstCall.args[0].type,
+      at.OPEN_DOWNLOAD_FILE
+    );
+    assert.deepEqual(
+      DEFAULT_PROPS.dispatch.firstCall.args[0].data,
+      downloadLink
+    );
+  });
+  it("should send OPEN_LINK if we clicked on anything other than a download", () => {
+    const nonDownloadLink = {
+      type: "history",
+      url: "download.mov",
+    };
+    wrapper = mountCardWithProps(
+      Object.assign({}, DEFAULT_PROPS, { link: nonDownloadLink })
+    );
+    const card = wrapper.find(".card");
+    const event = {
+      altKey: "1",
+      button: "2",
+      ctrlKey: "3",
+      metaKey: "4",
+      shiftKey: "5",
+    };
+    card.simulate(
+      "click",
+      Object.assign({}, event, { preventDefault: () => {} })
+    );
+    assert.calledThrice(DEFAULT_PROPS.dispatch);
+
+    assert.equal(DEFAULT_PROPS.dispatch.firstCall.args[0].type, at.OPEN_LINK);
+  });
+  describe("card image display", () => {
+    const DEFAULT_BLOB_URL = "blob://test";
+    let url;
+    beforeEach(() => {
+      url = {
+        createObjectURL: globals.sandbox.stub().returns(DEFAULT_BLOB_URL),
+        revokeObjectURL: globals.sandbox.spy(),
+      };
+      globals.set("URL", url);
+    });
+    afterEach(() => {
+      globals.restore();
+    });
+    it("should display a regular image correctly and not call revokeObjectURL when unmounted", () => {
+      wrapper = shallow(<Card {...DEFAULT_PROPS} />);
+
+      assert.isUndefined(wrapper.state("cardImage").path);
+      assert.equal(wrapper.state("cardImage").url, DEFAULT_PROPS.link.image);
+      assert.equal(
+        wrapper.find(".card-preview-image").props().style.backgroundImage,
+        `url(${wrapper.state("cardImage").url})`
+      );
+
+      wrapper.unmount();
+      assert.notCalled(url.revokeObjectURL);
+    });
+    it("should display a blob image correctly and revoke blob url when unmounted", () => {
+      const link = Object.assign({}, DEFAULT_PROPS.link, {
+        image: DEFAULT_BLOB_IMAGE,
+      });
+      wrapper = shallow(<Card {...DEFAULT_PROPS} link={link} />);
+
+      assert.equal(wrapper.state("cardImage").path, DEFAULT_BLOB_IMAGE.path);
+      assert.equal(wrapper.state("cardImage").url, DEFAULT_BLOB_URL);
+      assert.equal(
+        wrapper.find(".card-preview-image").props().style.backgroundImage,
+        `url(${wrapper.state("cardImage").url})`
+      );
+
+      wrapper.unmount();
+      assert.calledOnce(url.revokeObjectURL);
+    });
+    it("should not show an image if there isn't one and not call revokeObjectURL when unmounted", () => {
+      const link = Object.assign({}, DEFAULT_PROPS.link);
+      delete link.image;
+
+      wrapper = shallow(<Card {...DEFAULT_PROPS} link={link} />);
+
+      assert.isNull(wrapper.state("cardImage"));
+      assert.lengthOf(wrapper.find(".card-preview-image"), 0);
+
+      wrapper.unmount();
+      assert.notCalled(url.revokeObjectURL);
+    });
+    it("should remove current card image if new image is not present", () => {
+      wrapper = shallow(<Card {...DEFAULT_PROPS} />);
+
+      const otherLink = Object.assign({}, DEFAULT_PROPS.link);
+      delete otherLink.image;
+      wrapper.setProps(Object.assign({}, DEFAULT_PROPS, { link: otherLink }));
+
+      assert.isNull(wrapper.state("cardImage"));
+    });
+    it("should not create or revoke urls if normal image is already in state", () => {
+      wrapper = shallow(<Card {...DEFAULT_PROPS} />);
+
+      wrapper.setProps(DEFAULT_PROPS);
+
+      assert.notCalled(url.createObjectURL);
+      assert.notCalled(url.revokeObjectURL);
+    });
+    it("should not create or revoke more urls if blob image is already in state", () => {
+      const link = Object.assign({}, DEFAULT_PROPS.link, {
+        image: DEFAULT_BLOB_IMAGE,
+      });
+      wrapper = shallow(<Card {...DEFAULT_PROPS} link={link} />);
+
+      assert.calledOnce(url.createObjectURL);
+      assert.notCalled(url.revokeObjectURL);
+
+      wrapper.setProps(Object.assign({}, DEFAULT_PROPS, { link }));
+
+      assert.calledOnce(url.createObjectURL);
+      assert.notCalled(url.revokeObjectURL);
+    });
+    it("should create blob urls for new blobs and revoke existing ones", () => {
+      const link = Object.assign({}, DEFAULT_PROPS.link, {
+        image: DEFAULT_BLOB_IMAGE,
+      });
+      wrapper = shallow(<Card {...DEFAULT_PROPS} link={link} />);
+
+      assert.calledOnce(url.createObjectURL);
+      assert.notCalled(url.revokeObjectURL);
+
+      const otherLink = Object.assign({}, DEFAULT_PROPS.link, {
+        image: { path: "/newpath", data: new Blob([0]) },
+      });
+      wrapper.setProps(Object.assign({}, DEFAULT_PROPS, { link: otherLink }));
+
+      assert.calledTwice(url.createObjectURL);
+      assert.calledOnce(url.revokeObjectURL);
+    });
+    it("should not call createObjectURL and revokeObjectURL for normal images", () => {
+      wrapper = shallow(<Card {...DEFAULT_PROPS} />);
+
+      assert.notCalled(url.createObjectURL);
+      assert.notCalled(url.revokeObjectURL);
+
+      const otherLink = Object.assign({}, DEFAULT_PROPS.link, {
+        image: "https://other/image",
+      });
+      wrapper.setProps(Object.assign({}, DEFAULT_PROPS, { link: otherLink }));
+
+      assert.notCalled(url.createObjectURL);
+      assert.notCalled(url.revokeObjectURL);
+    });
+  });
+  describe("image loading", () => {
+    let link;
+    let triggerImage = {};
+    let uniqueLink = 0;
+    beforeEach(() => {
+      global.Image.prototype = {
+        addEventListener(event, callback) {
+          triggerImage[event] = () => Promise.resolve(callback());
+        },
+      };
+
+      link = Object.assign({}, DEFAULT_PROPS.link);
+      link.image += uniqueLink++;
+      wrapper = shallow(<Card {...DEFAULT_PROPS} link={link} />);
+    });
+    it("should have a loaded preview image when the image is loaded", () => {
+      assert.isFalse(wrapper.find(".card-preview-image").hasClass("loaded"));
+
+      wrapper.setState({ imageLoaded: true });
+
+      assert.isTrue(wrapper.find(".card-preview-image").hasClass("loaded"));
+    });
+    it("should start not loaded", () => {
+      assert.isFalse(wrapper.state("imageLoaded"));
+    });
+    it("should be loaded after load", async () => {
+      await triggerImage.load();
+
+      assert.isTrue(wrapper.state("imageLoaded"));
+    });
+    it("should be not be loaded after error ", async () => {
+      await triggerImage.error();
+
+      assert.isFalse(wrapper.state("imageLoaded"));
+    });
+    it("should be not be loaded if image changes", async () => {
+      await triggerImage.load();
+      const otherLink = Object.assign({}, link, {
+        image: "https://other/image",
+      });
+
+      wrapper.setProps(Object.assign({}, DEFAULT_PROPS, { link: otherLink }));
+
+      assert.isFalse(wrapper.state("imageLoaded"));
+    });
+  });
+  describe("placeholder=true", () => {
+    beforeEach(() => {
+      wrapper = mount(<Card placeholder={true} />);
+    });
+    it("should render when placeholder=true", () => {
+      assert.ok(wrapper.exists());
+    });
+    it("should add a placeholder class to the outer element", () => {
+      assert.isTrue(wrapper.find(".card-outer").hasClass("placeholder"));
+    });
+    it("should not have a context menu button or LinkMenu", () => {
+      assert.isFalse(
+        wrapper.find(ContextMenuButton).exists(),
+        "context menu button"
+      );
+      assert.isFalse(wrapper.find(LinkMenu).exists(), "LinkMenu");
+    });
+    it("should not call onLinkClick when the link is clicked", () => {
+      const spy = sinon.spy(wrapper.instance(), "onLinkClick");
+      const card = wrapper.find(".card");
+      card.simulate("click");
+      assert.notCalled(spy);
+    });
+  });
+  describe("#trackClick", () => {
+    it("should call dispatch when the link is clicked with the right data", () => {
+      const card = wrapper.find(".card");
+      const event = {
+        altKey: "1",
+        button: "2",
+        ctrlKey: "3",
+        metaKey: "4",
+        shiftKey: "5",
+      };
+      card.simulate(
+        "click",
+        Object.assign({}, event, { preventDefault: () => {} })
+      );
+      assert.calledThrice(DEFAULT_PROPS.dispatch);
+
+      // first dispatch call is the AlsoToMain message which will open a link in a window, and send some event data
+      assert.equal(DEFAULT_PROPS.dispatch.firstCall.args[0].type, at.OPEN_LINK);
+      assert.deepEqual(
+        DEFAULT_PROPS.dispatch.firstCall.args[0].data.event,
+        event
+      );
+
+      // second dispatch call is a UserEvent action for telemetry
+      assert.isUserEventAction(DEFAULT_PROPS.dispatch.secondCall.args[0]);
+      assert.calledWith(
+        DEFAULT_PROPS.dispatch.secondCall,
+        ac.UserEvent({
+          event: "CLICK",
+          source: DEFAULT_PROPS.eventSource,
+          action_position: DEFAULT_PROPS.index,
+        })
+      );
+
+      // third dispatch call is to send impression stats
+      assert.calledWith(
+        DEFAULT_PROPS.dispatch.thirdCall,
+        ac.ImpressionStats({
+          source: DEFAULT_PROPS.eventSource,
+          click: 0,
+          tiles: [{ id: DEFAULT_PROPS.link.guid, pos: DEFAULT_PROPS.index }],
+        })
+      );
+    });
+    it("should provide card_type to telemetry info if type is not history", () => {
+      const link = Object.assign({}, DEFAULT_PROPS.link);
+      link.type = "bookmark";
+      wrapper = mount(<Card {...Object.assign({}, DEFAULT_PROPS, { link })} />);
+      const card = wrapper.find(".card");
+      const event = {
+        altKey: "1",
+        button: "2",
+        ctrlKey: "3",
+        metaKey: "4",
+        shiftKey: "5",
+      };
+
+      card.simulate(
+        "click",
+        Object.assign({}, event, { preventDefault: () => {} })
+      );
+
+      assert.isUserEventAction(DEFAULT_PROPS.dispatch.secondCall.args[0]);
+      assert.calledWith(
+        DEFAULT_PROPS.dispatch.secondCall,
+        ac.UserEvent({
+          event: "CLICK",
+          source: DEFAULT_PROPS.eventSource,
+          action_position: DEFAULT_PROPS.index,
+          value: { card_type: link.type },
+        })
+      );
+    });
+    it("should notify Web Extensions with WEBEXT_CLICK if props.isWebExtension is true", () => {
+      wrapper = mountCardWithProps(
+        Object.assign({}, DEFAULT_PROPS, {
+          isWebExtension: true,
+          eventSource: "MyExtension",
+          index: 3,
+        })
+      );
+      const card = wrapper.find(".card");
+      const event = { preventDefault() {} };
+      card.simulate("click", event);
+      assert.calledWith(
+        DEFAULT_PROPS.dispatch,
+        ac.WebExtEvent(at.WEBEXT_CLICK, {
+          source: "MyExtension",
+          url: DEFAULT_PROPS.link.url,
+          action_position: 3,
+        })
+      );
+    });
+  });
+});
+
+describe("<PlaceholderCard />", () => {
+  it("should render a Card with placeholder=true", () => {
+    const wrapper = mount(
+      <Provider store={createStore(combineReducers(reducers), INITIAL_STATE)}>
+        <PlaceholderCard />
+      </Provider>
+    );
+    assert.isTrue(wrapper.find(Card).props().placeholder);
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/CollapsibleSection.test.jsx b/browser/components/newtab/test/unit/content-src/components/CollapsibleSection.test.jsx
new file mode 100644
index 0000000000..f2a8e276b4
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/CollapsibleSection.test.jsx
@@ -0,0 +1,67 @@
+import { _CollapsibleSection as CollapsibleSection } from "content-src/components/CollapsibleSection/CollapsibleSection";
+import { ErrorBoundary } from "content-src/components/ErrorBoundary/ErrorBoundary";
+import { mount } from "enzyme";
+import React from "react";
+
+const DEFAULT_PROPS = {
+  id: "cool",
+  className: "cool-section",
+  title: "Cool Section",
+  prefName: "collapseSection",
+  collapsed: false,
+  eventSource: "foo",
+  document: {
+    addEventListener: () => {},
+    removeEventListener: () => {},
+    visibilityState: "visible",
+  },
+  dispatch: () => {},
+  Prefs: { values: { featureConfig: {} } },
+};
+
+describe("CollapsibleSection", () => {
+  let wrapper;
+
+  function setup(props = {}) {
+    const customProps = Object.assign({}, DEFAULT_PROPS, props);
+    wrapper = mount(
+      <CollapsibleSection {...customProps}>foo</CollapsibleSection>
+    );
+  }
+
+  beforeEach(() => setup());
+
+  it("should render the component", () => {
+    assert.ok(wrapper.exists());
+  });
+
+  it("should render an ErrorBoundary with class section-body-fallback", () => {
+    assert.equal(
+      wrapper.find(ErrorBoundary).first().prop("className"),
+      "section-body-fallback"
+    );
+  });
+
+  describe("without collapsible pref", () => {
+    let dispatch;
+    beforeEach(() => {
+      dispatch = sinon.stub();
+      setup({ collapsed: undefined, dispatch });
+    });
+    it("should render the section uncollapsed", () => {
+      assert.isFalse(
+        wrapper.find(".collapsible-section").first().hasClass("collapsed")
+      );
+    });
+
+    it("should not render the arrow if no collapsible pref exists for the section", () => {
+      assert.lengthOf(wrapper.find(".click-target .collapsible-arrow"), 0);
+    });
+  });
+
+  describe("icon", () => {
+    it("no icon should be shown", () => {
+      assert.lengthOf(wrapper.find(".icon"), 0);
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/ComponentPerfTimer.test.jsx b/browser/components/newtab/test/unit/content-src/components/ComponentPerfTimer.test.jsx
new file mode 100644
index 0000000000..baf203947e
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/ComponentPerfTimer.test.jsx
@@ -0,0 +1,447 @@
+import {
+  actionCreators as ac,
+  actionTypes as at,
+} from "common/Actions.sys.mjs";
+import { ComponentPerfTimer } from "content-src/components/ComponentPerfTimer/ComponentPerfTimer";
+import createMockRaf from "mock-raf";
+import React from "react";
+
+import { shallow } from "enzyme";
+
+const perfSvc = {
+  mark() {},
+  getMostRecentAbsMarkStartByName() {},
+};
+
+let DEFAULT_PROPS = {
+  initialized: true,
+  rows: [],
+  id: "highlights",
+  dispatch() {},
+  perfSvc,
+};
+
+describe("<ComponentPerfTimer>", () => {
+  let mockRaf;
+  let sandbox;
+  let wrapper;
+
+  const InnerEl = () => <div>Inner Element</div>;
+
+  beforeEach(() => {
+    mockRaf = createMockRaf();
+    sandbox = sinon.createSandbox();
+    sandbox.stub(window, "requestAnimationFrame").callsFake(mockRaf.raf);
+    wrapper = shallow(
+      <ComponentPerfTimer {...DEFAULT_PROPS}>
+        <InnerEl />
+      </ComponentPerfTimer>
+    );
+  });
+  afterEach(() => {
+    sandbox.restore();
+  });
+
+  it("should render props.children", () => {
+    assert.ok(wrapper.contains(<InnerEl />));
+  });
+
+  describe("#constructor", () => {
+    beforeEach(() => {
+      sandbox.stub(ComponentPerfTimer.prototype, "_maybeSendBadStateEvent");
+      sandbox.stub(
+        ComponentPerfTimer.prototype,
+        "_ensureFirstRenderTsRecorded"
+      );
+      wrapper = shallow(
+        <ComponentPerfTimer {...DEFAULT_PROPS}>
+          <InnerEl />
+        </ComponentPerfTimer>,
+        { disableLifecycleMethods: true }
+      );
+    });
+
+    it("should have the correct defaults", () => {
+      const instance = wrapper.instance();
+
+      assert.isFalse(instance._reportMissingData);
+      assert.isFalse(instance._timestampHandled);
+      assert.isFalse(instance._recordedFirstRender);
+    });
+  });
+
+  describe("#render", () => {
+    beforeEach(() => {
+      sandbox.stub(DEFAULT_PROPS, "id").value("fake_section");
+      sandbox.stub(ComponentPerfTimer.prototype, "_maybeSendBadStateEvent");
+      sandbox.stub(
+        ComponentPerfTimer.prototype,
+        "_ensureFirstRenderTsRecorded"
+      );
+      wrapper = shallow(
+        <ComponentPerfTimer {...DEFAULT_PROPS}>
+          <InnerEl />
+        </ComponentPerfTimer>
+      );
+    });
+
+    it("should not call telemetry on sections that we don't want to record", () => {
+      const instance = wrapper.instance();
+
+      assert.notCalled(instance._maybeSendBadStateEvent);
+      assert.notCalled(instance._ensureFirstRenderTsRecorded);
+    });
+  });
+
+  describe("#_componentDidMount", () => {
+    it("should call _maybeSendPaintedEvent", () => {
+      const instance = wrapper.instance();
+      const stub = sandbox.stub(instance, "_maybeSendPaintedEvent");
+
+      instance.componentDidMount();
+
+      assert.calledOnce(stub);
+    });
+
+    it("should not call _maybeSendPaintedEvent if id not in RECORDED_SECTIONS", () => {
+      sandbox.stub(DEFAULT_PROPS, "id").value("topstories");
+      wrapper = shallow(
+        <ComponentPerfTimer {...DEFAULT_PROPS}>
+          <InnerEl />
+        </ComponentPerfTimer>
+      );
+      const instance = wrapper.instance();
+      const stub = sandbox.stub(instance, "_maybeSendPaintedEvent");
+
+      instance.componentDidMount();
+
+      assert.notCalled(stub);
+    });
+  });
+
+  describe("#_componentDidUpdate", () => {
+    it("should call _maybeSendPaintedEvent", () => {
+      const instance = wrapper.instance();
+      const maybeSendPaintStub = sandbox.stub(
+        instance,
+        "_maybeSendPaintedEvent"
+      );
+
+      instance.componentDidUpdate();
+
+      assert.calledOnce(maybeSendPaintStub);
+    });
+
+    it("should not call _maybeSendPaintedEvent if id not in RECORDED_SECTIONS", () => {
+      sandbox.stub(DEFAULT_PROPS, "id").value("topstories");
+      wrapper = shallow(
+        <ComponentPerfTimer {...DEFAULT_PROPS}>
+          <InnerEl />
+        </ComponentPerfTimer>
+      );
+      const instance = wrapper.instance();
+      const stub = sandbox.stub(instance, "_maybeSendPaintedEvent");
+
+      instance.componentDidUpdate();
+
+      assert.notCalled(stub);
+    });
+  });
+
+  describe("_ensureFirstRenderTsRecorded", () => {
+    let recordFirstRenderStub;
+    beforeEach(() => {
+      sandbox.stub(ComponentPerfTimer.prototype, "_maybeSendBadStateEvent");
+      recordFirstRenderStub = sandbox.stub(
+        ComponentPerfTimer.prototype,
+        "_ensureFirstRenderTsRecorded"
+      );
+    });
+
+    it("should set _recordedFirstRender", () => {
+      sandbox.stub(DEFAULT_PROPS, "initialized").value(false);
+      wrapper = shallow(
+        <ComponentPerfTimer {...DEFAULT_PROPS}>
+          <InnerEl />
+        </ComponentPerfTimer>
+      );
+      const instance = wrapper.instance();
+
+      assert.isFalse(instance._recordedFirstRender);
+
+      recordFirstRenderStub.callThrough();
+      instance._ensureFirstRenderTsRecorded();
+
+      assert.isTrue(instance._recordedFirstRender);
+    });
+
+    it("should mark first_render_ts", () => {
+      sandbox.stub(DEFAULT_PROPS, "initialized").value(false);
+      wrapper = shallow(
+        <ComponentPerfTimer {...DEFAULT_PROPS}>
+          <InnerEl />
+        </ComponentPerfTimer>
+      );
+      const instance = wrapper.instance();
+      const stub = sandbox.stub(perfSvc, "mark");
+
+      recordFirstRenderStub.callThrough();
+      instance._ensureFirstRenderTsRecorded();
+
+      assert.calledOnce(stub);
+      assert.calledWithExactly(stub, `${DEFAULT_PROPS.id}_first_render_ts`);
+    });
+  });
+
+  describe("#_maybeSendBadStateEvent", () => {
+    let sendBadStateStub;
+    beforeEach(() => {
+      sendBadStateStub = sandbox.stub(
+        ComponentPerfTimer.prototype,
+        "_maybeSendBadStateEvent"
+      );
+      sandbox.stub(
+        ComponentPerfTimer.prototype,
+        "_ensureFirstRenderTsRecorded"
+      );
+    });
+
+    it("should set this._reportMissingData=true when called with initialized === false", () => {
+      sandbox.stub(DEFAULT_PROPS, "initialized").value(false);
+      wrapper = shallow(
+        <ComponentPerfTimer {...DEFAULT_PROPS}>
+          <InnerEl />
+        </ComponentPerfTimer>
+      );
+      const instance = wrapper.instance();
+
+      assert.isFalse(instance._reportMissingData);
+
+      sendBadStateStub.callThrough();
+      instance._maybeSendBadStateEvent();
+
+      assert.isTrue(instance._reportMissingData);
+    });
+
+    it("should call _sendBadStateEvent if initialized & other metrics have been recorded", () => {
+      const instance = wrapper.instance();
+      const stub = sandbox.stub(instance, "_sendBadStateEvent");
+      instance._reportMissingData = true;
+      instance._timestampHandled = true;
+      instance._recordedFirstRender = true;
+
+      sendBadStateStub.callThrough();
+      instance._maybeSendBadStateEvent();
+
+      assert.calledOnce(stub);
+      assert.isFalse(instance._reportMissingData);
+    });
+  });
+
+  describe("#_maybeSendPaintedEvent", () => {
+    it("should call _sendPaintedEvent if props.initialized is true", () => {
+      sandbox.stub(DEFAULT_PROPS, "initialized").value(true);
+      wrapper = shallow(
+        <ComponentPerfTimer {...DEFAULT_PROPS}>
+          <InnerEl />
+        </ComponentPerfTimer>,
+        { disableLifecycleMethods: true }
+      );
+      const instance = wrapper.instance();
+      const stub = sandbox.stub(instance, "_afterFramePaint");
+
+      assert.isFalse(instance._timestampHandled);
+
+      instance._maybeSendPaintedEvent();
+
+      assert.calledOnce(stub);
+      assert.calledWithExactly(stub, instance._sendPaintedEvent);
+      assert.isTrue(wrapper.instance()._timestampHandled);
+    });
+    it("should not call _sendPaintedEvent if this._timestampHandled is true", () => {
+      const instance = wrapper.instance();
+      const spy = sinon.spy(instance, "_afterFramePaint");
+      instance._timestampHandled = true;
+
+      instance._maybeSendPaintedEvent();
+      spy.neverCalledWith(instance._sendPaintedEvent);
+    });
+    it("should not call _sendPaintedEvent if component not initialized", () => {
+      sandbox.stub(DEFAULT_PROPS, "initialized").value(false);
+      wrapper = shallow(
+        <ComponentPerfTimer {...DEFAULT_PROPS}>
+          <InnerEl />
+        </ComponentPerfTimer>
+      );
+      const instance = wrapper.instance();
+      const spy = sinon.spy(instance, "_afterFramePaint");
+
+      instance._maybeSendPaintedEvent();
+
+      spy.neverCalledWith(instance._sendPaintedEvent);
+    });
+  });
+
+  describe("#_afterFramePaint", () => {
+    it("should call callback after the requestAnimationFrame callback returns", () =>
+      new Promise(resolve => {
+        // Setting the callback to resolve is the test that it does finally get
+        // called at the correct time, after the event loop ticks again.
+        // If it doesn't get called, this test will time out.
+        const callback = sandbox.spy(resolve);
+
+        const instance = wrapper.instance();
+
+        instance._afterFramePaint(callback);
+
+        assert.notCalled(callback);
+        mockRaf.step({ count: 1 });
+      }));
+  });
+
+  describe("#_sendBadStateEvent", () => {
+    it("should call perfSvc.mark", () => {
+      sandbox.spy(perfSvc, "mark");
+      const key = `${DEFAULT_PROPS.id}_data_ready_ts`;
+
+      wrapper.instance()._sendBadStateEvent();
+
+      assert.calledOnce(perfSvc.mark);
+      assert.calledWithExactly(perfSvc.mark, key);
+    });
+
+    it("should call compute the delta from first render to data ready", () => {
+      sandbox.stub(perfSvc, "getMostRecentAbsMarkStartByName");
+
+      wrapper
+        .instance()
+        ._sendBadStateEvent(`${DEFAULT_PROPS.id}_data_ready_ts`);
+
+      assert.calledTwice(perfSvc.getMostRecentAbsMarkStartByName);
+      assert.calledWithExactly(
+        perfSvc.getMostRecentAbsMarkStartByName,
+        `${DEFAULT_PROPS.id}_data_ready_ts`
+      );
+      assert.calledWithExactly(
+        perfSvc.getMostRecentAbsMarkStartByName,
+        `${DEFAULT_PROPS.id}_first_render_ts`
+      );
+    });
+
+    it("should call dispatch SAVE_SESSION_PERF_DATA", () => {
+      sandbox
+        .stub(perfSvc, "getMostRecentAbsMarkStartByName")
+        .withArgs("highlights_first_render_ts")
+        .returns(0.5)
+        .withArgs("highlights_data_ready_ts")
+        .returns(3.2);
+
+      const dispatch = sandbox.spy(DEFAULT_PROPS, "dispatch");
+      wrapper = shallow(
+        <ComponentPerfTimer {...DEFAULT_PROPS}>
+          <InnerEl />
+        </ComponentPerfTimer>
+      );
+
+      wrapper.instance()._sendBadStateEvent();
+
+      assert.calledOnce(dispatch);
+      assert.calledWithExactly(
+        dispatch,
+        ac.OnlyToMain({
+          type: at.SAVE_SESSION_PERF_DATA,
+          data: { [`${DEFAULT_PROPS.id}_data_late_by_ms`]: 2 },
+        })
+      );
+    });
+  });
+
+  describe("#_sendPaintedEvent", () => {
+    beforeEach(() => {
+      sandbox.stub(ComponentPerfTimer.prototype, "_maybeSendBadStateEvent");
+      sandbox.stub(
+        ComponentPerfTimer.prototype,
+        "_ensureFirstRenderTsRecorded"
+      );
+    });
+
+    it("should not call mark with the wrong id", () => {
+      sandbox.stub(perfSvc, "mark");
+      sandbox.stub(DEFAULT_PROPS, "id").value("fake_id");
+      wrapper = shallow(
+        <ComponentPerfTimer {...DEFAULT_PROPS}>
+          <InnerEl />
+        </ComponentPerfTimer>
+      );
+
+      wrapper.instance()._sendPaintedEvent();
+
+      assert.notCalled(perfSvc.mark);
+    });
+    it("should call mark with the correct topsites", () => {
+      sandbox.stub(perfSvc, "mark");
+      sandbox.stub(DEFAULT_PROPS, "id").value("topsites");
+      wrapper = shallow(
+        <ComponentPerfTimer {...DEFAULT_PROPS}>
+          <InnerEl />
+        </ComponentPerfTimer>
+      );
+
+      wrapper.instance()._sendPaintedEvent();
+
+      assert.calledOnce(perfSvc.mark);
+      assert.calledWithExactly(perfSvc.mark, "topsites_first_painted_ts");
+    });
+    it("should not call getMostRecentAbsMarkStartByName if id!=topsites", () => {
+      sandbox.stub(perfSvc, "getMostRecentAbsMarkStartByName");
+      sandbox.stub(DEFAULT_PROPS, "id").value("fake_id");
+      wrapper = shallow(
+        <ComponentPerfTimer {...DEFAULT_PROPS}>
+          <InnerEl />
+        </ComponentPerfTimer>
+      );
+
+      wrapper.instance()._sendPaintedEvent();
+
+      assert.notCalled(perfSvc.getMostRecentAbsMarkStartByName);
+    });
+    it("should call getMostRecentAbsMarkStartByName for topsites", () => {
+      sandbox.stub(perfSvc, "getMostRecentAbsMarkStartByName");
+      sandbox.stub(DEFAULT_PROPS, "id").value("topsites");
+      wrapper = shallow(
+        <ComponentPerfTimer {...DEFAULT_PROPS}>
+          <InnerEl />
+        </ComponentPerfTimer>
+      );
+
+      wrapper.instance()._sendPaintedEvent();
+
+      assert.calledOnce(perfSvc.getMostRecentAbsMarkStartByName);
+      assert.calledWithExactly(
+        perfSvc.getMostRecentAbsMarkStartByName,
+        "topsites_first_painted_ts"
+      );
+    });
+    it("should dispatch SAVE_SESSION_PERF_DATA", () => {
+      sandbox.stub(perfSvc, "getMostRecentAbsMarkStartByName").returns(42);
+      sandbox.stub(DEFAULT_PROPS, "id").value("topsites");
+      const dispatch = sandbox.spy(DEFAULT_PROPS, "dispatch");
+      wrapper = shallow(
+        <ComponentPerfTimer {...DEFAULT_PROPS}>
+          <InnerEl />
+        </ComponentPerfTimer>
+      );
+
+      wrapper.instance()._sendPaintedEvent();
+
+      assert.calledOnce(dispatch);
+      assert.calledWithExactly(
+        dispatch,
+        ac.OnlyToMain({
+          type: at.SAVE_SESSION_PERF_DATA,
+          data: { topsites_first_painted_ts: 42 },
+        })
+      );
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/ConfirmDialog.test.jsx b/browser/components/newtab/test/unit/content-src/components/ConfirmDialog.test.jsx
new file mode 100644
index 0000000000..a471c09e66
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/ConfirmDialog.test.jsx
@@ -0,0 +1,182 @@
+import {
+  actionCreators as ac,
+  actionTypes as at,
+} from "common/Actions.sys.mjs";
+import { _ConfirmDialog as ConfirmDialog } from "content-src/components/ConfirmDialog/ConfirmDialog";
+import React from "react";
+import { shallow } from "enzyme";
+
+describe("<ConfirmDialog>", () => {
+  let wrapper;
+  let dispatch;
+  let ConfirmDialogProps;
+  beforeEach(() => {
+    dispatch = sinon.stub();
+    ConfirmDialogProps = {
+      visible: true,
+      data: {
+        onConfirm: [],
+        cancel_button_string_id: "newtab-topsites-delete-history-button",
+        confirm_button_string_id: "newtab-topsites-cancel-button",
+        eventSource: "HIGHLIGHTS",
+      },
+    };
+    wrapper = shallow(
+      <ConfirmDialog dispatch={dispatch} {...ConfirmDialogProps} />
+    );
+  });
+  it("should render an overlay", () => {
+    assert.ok(wrapper.find(".modal-overlay").exists());
+  });
+  it("should render a modal", () => {
+    assert.ok(wrapper.find(".confirmation-dialog").exists());
+  });
+  it("should not render if visible is false", () => {
+    ConfirmDialogProps.visible = false;
+    wrapper = shallow(
+      <ConfirmDialog dispatch={dispatch} {...ConfirmDialogProps} />
+    );
+
+    assert.lengthOf(wrapper.find(".confirmation-dialog"), 0);
+  });
+  it("should display an icon if we provide one in props", () => {
+    const iconName = "modal-icon";
+    // If there is no icon in the props, we shouldn't display an icon
+    assert.lengthOf(wrapper.find(`.icon-${iconName}`), 0);
+
+    ConfirmDialogProps.data.icon = iconName;
+    wrapper = shallow(
+      <ConfirmDialog dispatch={dispatch} {...ConfirmDialogProps} />
+    );
+
+    // But if we do provide an icon - we should show it
+    assert.lengthOf(wrapper.find(`.icon-${iconName}`), 1);
+  });
+  describe("fluent message check", () => {
+    it("should render the message body sent via props", () => {
+      Object.assign(ConfirmDialogProps.data, {
+        body_string_id: ["foo", "bar"],
+      });
+      wrapper = shallow(
+        <ConfirmDialog dispatch={dispatch} {...ConfirmDialogProps} />
+      );
+      let msgs = wrapper.find(".modal-message").find("p");
+      assert.equal(msgs.length, ConfirmDialogProps.data.body_string_id.length);
+      msgs.forEach((fm, i) =>
+        assert.equal(
+          fm.prop("data-l10n-id"),
+          ConfirmDialogProps.data.body_string_id[i]
+        )
+      );
+    });
+    it("should render the correct primary button text", () => {
+      Object.assign(ConfirmDialogProps.data, {
+        confirm_button_string_id: "primary_foo",
+      });
+      wrapper = shallow(
+        <ConfirmDialog dispatch={dispatch} {...ConfirmDialogProps} />
+      );
+
+      let doneLabel = wrapper.find(".actions").childAt(1);
+      assert.ok(doneLabel.exists());
+      assert.equal(
+        doneLabel.prop("data-l10n-id"),
+        ConfirmDialogProps.data.confirm_button_string_id
+      );
+    });
+  });
+  describe("click events", () => {
+    it("should emit AlsoToMain DIALOG_CANCEL when you click the overlay", () => {
+      let overlay = wrapper.find(".modal-overlay");
+
+      assert.ok(overlay.exists());
+      overlay.simulate("click");
+
+      // Two events are emitted: UserEvent+AlsoToMain.
+      assert.calledTwice(dispatch);
+      assert.propertyVal(dispatch.firstCall.args[0], "type", at.DIALOG_CANCEL);
+      assert.calledWith(dispatch, { type: at.DIALOG_CANCEL });
+    });
+    it("should emit UserEvent DIALOG_CANCEL when you click the overlay", () => {
+      let overlay = wrapper.find(".modal-overlay");
+
+      assert.ok(overlay);
+      overlay.simulate("click");
+
+      // Two events are emitted: UserEvent+AlsoToMain.
+      assert.calledTwice(dispatch);
+      assert.isUserEventAction(dispatch.secondCall.args[0]);
+      assert.calledWith(
+        dispatch,
+        ac.UserEvent({ event: at.DIALOG_CANCEL, source: "HIGHLIGHTS" })
+      );
+    });
+    it("should emit AlsoToMain DIALOG_CANCEL on cancel", () => {
+      let cancelButton = wrapper.find(".actions").childAt(0);
+
+      assert.ok(cancelButton);
+      cancelButton.simulate("click");
+
+      // Two events are emitted: UserEvent+AlsoToMain.
+      assert.calledTwice(dispatch);
+      assert.propertyVal(dispatch.firstCall.args[0], "type", at.DIALOG_CANCEL);
+      assert.calledWith(dispatch, { type: at.DIALOG_CANCEL });
+    });
+    it("should emit UserEvent DIALOG_CANCEL on cancel", () => {
+      let cancelButton = wrapper.find(".actions").childAt(0);
+
+      assert.ok(cancelButton);
+      cancelButton.simulate("click");
+
+      // Two events are emitted: UserEvent+AlsoToMain.
+      assert.calledTwice(dispatch);
+      assert.isUserEventAction(dispatch.secondCall.args[0]);
+      assert.calledWith(
+        dispatch,
+        ac.UserEvent({ event: at.DIALOG_CANCEL, source: "HIGHLIGHTS" })
+      );
+    });
+    it("should emit UserEvent on primary button", () => {
+      Object.assign(ConfirmDialogProps.data, {
+        body_string_id: ["foo", "bar"],
+        onConfirm: [
+          ac.AlsoToMain({ type: at.DELETE_URL, data: "foo.bar" }),
+          ac.UserEvent({ event: "DELETE" }),
+        ],
+      });
+      wrapper = shallow(
+        <ConfirmDialog dispatch={dispatch} {...ConfirmDialogProps} />
+      );
+      let doneButton = wrapper.find(".actions").childAt(1);
+
+      assert.ok(doneButton);
+      doneButton.simulate("click");
+
+      // Two events are emitted: UserEvent+AlsoToMain.
+      assert.isUserEventAction(dispatch.secondCall.args[0]);
+
+      assert.calledTwice(dispatch);
+      assert.calledWith(dispatch, ConfirmDialogProps.data.onConfirm[1]);
+    });
+    it("should emit AlsoToMain on primary button", () => {
+      Object.assign(ConfirmDialogProps.data, {
+        body_string_id: ["foo", "bar"],
+        onConfirm: [
+          ac.AlsoToMain({ type: at.DELETE_URL, data: "foo.bar" }),
+          ac.UserEvent({ event: "DELETE" }),
+        ],
+      });
+      wrapper = shallow(
+        <ConfirmDialog dispatch={dispatch} {...ConfirmDialogProps} />
+      );
+      let doneButton = wrapper.find(".actions").childAt(1);
+
+      assert.ok(doneButton);
+      doneButton.simulate("click");
+
+      // Two events are emitted: UserEvent+AlsoToMain.
+      assert.calledTwice(dispatch);
+      assert.calledWith(dispatch, ConfirmDialogProps.data.onConfirm[0]);
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/ContextMenu.test.jsx b/browser/components/newtab/test/unit/content-src/components/ContextMenu.test.jsx
new file mode 100644
index 0000000000..4f7edadc41
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/ContextMenu.test.jsx
@@ -0,0 +1,227 @@
+import {
+  ContextMenu,
+  ContextMenuItem,
+  _ContextMenuItem,
+} from "content-src/components/ContextMenu/ContextMenu";
+import { ContextMenuButton } from "content-src/components/ContextMenu/ContextMenuButton";
+import { mount, shallow } from "enzyme";
+import React from "react";
+import { INITIAL_STATE, reducers } from "common/Reducers.sys.mjs";
+import { Provider } from "react-redux";
+import { combineReducers, createStore } from "redux";
+
+const DEFAULT_PROPS = {
+  onUpdate: () => {},
+  options: [],
+  tabbableOptionsLength: 0,
+};
+
+const DEFAULT_MENU_OPTIONS = [
+  "MoveUp",
+  "MoveDown",
+  "Separator",
+  "ManageSection",
+];
+
+const FakeMenu = props => {
+  return <div>{props.children}</div>;
+};
+
+describe("<ContextMenuButton>", () => {
+  function mountWithProps(options) {
+    const store = createStore(combineReducers(reducers), INITIAL_STATE);
+    return mount(
+      <Provider store={store}>
+        <ContextMenuButton>
+          <ContextMenu options={options} />
+        </ContextMenuButton>
+      </Provider>
+    );
+  }
+
+  let sandbox;
+  beforeEach(() => {
+    sandbox = sinon.createSandbox();
+  });
+  afterEach(() => {
+    sandbox.restore();
+  });
+  it("should call onUpdate when clicked", () => {
+    const onUpdate = sandbox.spy();
+    const wrapper = mount(
+      <ContextMenuButton onUpdate={onUpdate}>
+        <FakeMenu />
+      </ContextMenuButton>
+    );
+    wrapper.find(".context-menu-button").simulate("click");
+    assert.calledOnce(onUpdate);
+  });
+  it("should call onUpdate when activated with Enter", () => {
+    const onUpdate = sandbox.spy();
+    const wrapper = mount(
+      <ContextMenuButton onUpdate={onUpdate}>
+        <FakeMenu />
+      </ContextMenuButton>
+    );
+    wrapper.find(".context-menu-button").simulate("keydown", { key: "Enter" });
+    assert.calledOnce(onUpdate);
+  });
+  it("should call onClick", () => {
+    const onClick = sandbox.spy(ContextMenuButton.prototype, "onClick");
+    const wrapper = mount(
+      <ContextMenuButton>
+        <FakeMenu />
+      </ContextMenuButton>
+    );
+    wrapper.find("button").simulate("click");
+    assert.calledOnce(onClick);
+  });
+  it("should have a default keyboardAccess prop of false", () => {
+    const wrapper = mountWithProps(DEFAULT_MENU_OPTIONS);
+    wrapper.find(ContextMenuButton).setState({ showContextMenu: true });
+    assert.equal(wrapper.find(ContextMenu).prop("keyboardAccess"), false);
+  });
+  it("should pass the keyboardAccess prop down to ContextMenu", () => {
+    const wrapper = mountWithProps(DEFAULT_MENU_OPTIONS);
+    wrapper
+      .find(ContextMenuButton)
+      .setState({ showContextMenu: true, contextMenuKeyboard: true });
+    assert.equal(wrapper.find(ContextMenu).prop("keyboardAccess"), true);
+  });
+  it("should call focusFirst when keyboardAccess is true", () => {
+    const options = [{ label: "item1", first: true }];
+    const wrapper = mountWithProps(options);
+    const focusFirst = sandbox.spy(_ContextMenuItem.prototype, "focusFirst");
+    wrapper
+      .find(ContextMenuButton)
+      .setState({ showContextMenu: true, contextMenuKeyboard: true });
+    assert.calledOnce(focusFirst);
+  });
+});
+
+describe("<ContextMenu>", () => {
+  function mountWithProps(props) {
+    const store = createStore(combineReducers(reducers), INITIAL_STATE);
+    return mount(
+      <Provider store={store}>
+        <ContextMenu {...props} />
+      </Provider>
+    );
+  }
+
+  it("should render all the options provided", () => {
+    const options = [
+      { label: "item1" },
+      { type: "separator" },
+      { label: "item2" },
+    ];
+    const wrapper = shallow(
+      <ContextMenu {...DEFAULT_PROPS} options={options} />
+    );
+    assert.lengthOf(wrapper.find(".context-menu-list").children(), 3);
+  });
+  it("should not add a link for a separator", () => {
+    const options = [{ label: "item1" }, { type: "separator" }];
+    const wrapper = shallow(
+      <ContextMenu {...DEFAULT_PROPS} options={options} />
+    );
+    assert.lengthOf(wrapper.find(".separator"), 1);
+  });
+  it("should add a link for all types that are not separators", () => {
+    const options = [{ label: "item1" }, { type: "separator" }];
+    const wrapper = shallow(
+      <ContextMenu {...DEFAULT_PROPS} options={options} />
+    );
+    assert.lengthOf(wrapper.find(ContextMenuItem), 1);
+  });
+  it("should not add an icon to any items", () => {
+    const props = Object.assign({}, DEFAULT_PROPS, {
+      options: [{ label: "item1", icon: "icon1" }, { type: "separator" }],
+    });
+    const wrapper = mountWithProps(props);
+    assert.lengthOf(wrapper.find(".icon-icon1"), 0);
+  });
+  it("should be tabbable", () => {
+    const props = {
+      options: [{ label: "item1", icon: "icon1" }, { type: "separator" }],
+    };
+    const wrapper = mountWithProps(props);
+    assert.equal(
+      wrapper.find(".context-menu-item").props().role,
+      "presentation"
+    );
+  });
+  it("should call onUpdate with false when an option is clicked", () => {
+    const onUpdate = sinon.spy();
+    const onClick = sinon.spy();
+    const props = Object.assign({}, DEFAULT_PROPS, {
+      onUpdate,
+      options: [{ label: "item1", onClick }],
+    });
+    const wrapper = mountWithProps(props);
+    wrapper.find(".context-menu-item button").simulate("click");
+    assert.calledOnce(onUpdate);
+    assert.calledOnce(onClick);
+  });
+  it("should not have disabled className by default", () => {
+    const props = Object.assign({}, DEFAULT_PROPS, {
+      options: [{ label: "item1", icon: "icon1" }, { type: "separator" }],
+    });
+    const wrapper = mountWithProps(props);
+    assert.lengthOf(wrapper.find(".context-menu-item a.disabled"), 0);
+  });
+  it("should add disabled className to any disabled options", () => {
+    const options = [
+      { label: "item1", icon: "icon1", disabled: true },
+      { type: "separator" },
+    ];
+    const props = Object.assign({}, DEFAULT_PROPS, { options });
+    const wrapper = mountWithProps(props);
+    assert.lengthOf(wrapper.find(".context-menu-item button.disabled"), 1);
+  });
+  it("should have the context-menu-item class", () => {
+    const options = [{ label: "item1", icon: "icon1" }];
+    const props = Object.assign({}, DEFAULT_PROPS, { options });
+    const wrapper = mountWithProps(props);
+    assert.lengthOf(wrapper.find(".context-menu-item"), 1);
+  });
+  it("should call onClick when onKeyDown is called with Enter", () => {
+    const onClick = sinon.spy();
+    const props = Object.assign({}, DEFAULT_PROPS, {
+      options: [{ label: "item1", onClick }],
+    });
+    const wrapper = mountWithProps(props);
+    wrapper
+      .find(".context-menu-item button")
+      .simulate("keydown", { key: "Enter" });
+    assert.calledOnce(onClick);
+  });
+  it("should call focusSibling when onKeyDown is called with ArrowUp", () => {
+    const props = Object.assign({}, DEFAULT_PROPS, {
+      options: [{ label: "item1" }],
+    });
+    const wrapper = mountWithProps(props);
+    const focusSibling = sinon.stub(
+      wrapper.find(_ContextMenuItem).instance(),
+      "focusSibling"
+    );
+    wrapper
+      .find(".context-menu-item button")
+      .simulate("keydown", { key: "ArrowUp" });
+    assert.calledOnce(focusSibling);
+  });
+  it("should call focusSibling when onKeyDown is called with ArrowDown", () => {
+    const props = Object.assign({}, DEFAULT_PROPS, {
+      options: [{ label: "item1" }],
+    });
+    const wrapper = mountWithProps(props);
+    const focusSibling = sinon.stub(
+      wrapper.find(_ContextMenuItem).instance(),
+      "focusSibling"
+    );
+    wrapper
+      .find(".context-menu-item button")
+      .simulate("keydown", { key: "ArrowDown" });
+    assert.calledOnce(focusSibling);
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/CustomiseMenu.test.jsx b/browser/components/newtab/test/unit/content-src/components/CustomiseMenu.test.jsx
new file mode 100644
index 0000000000..e1f84f7d84
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/CustomiseMenu.test.jsx
@@ -0,0 +1,72 @@
+import { actionCreators as ac } from "common/Actions.sys.mjs";
+import { ContentSection } from "content-src/components/CustomizeMenu/ContentSection/ContentSection";
+import { mount } from "enzyme";
+import React from "react";
+
+const DEFAULT_PROPS = {
+  enabledSections: {
+    pocketEnabled: true,
+    topSitesEnabled: true,
+  },
+  mayHaveSponsoredTopSites: true,
+  mayHaveSponsoredStories: true,
+  pocketRegion: true,
+  dispatch: sinon.stub(),
+  setPref: sinon.stub(),
+};
+
+describe("ContentSection", () => {
+  let wrapper;
+  beforeEach(() => {
+    wrapper = mount(<ContentSection {...DEFAULT_PROPS} />);
+  });
+
+  it("should render the component", () => {
+    assert.ok(wrapper.exists());
+  });
+
+  it("should look for a data-eventSource attribute and dispatch an event for INPUT", () => {
+    wrapper.instance().onPreferenceSelect({
+      target: {
+        nodeName: "INPUT",
+        checked: true,
+        dataset: { preference: "foo", eventSource: "bar" },
+      },
+    });
+
+    assert.calledWith(
+      DEFAULT_PROPS.dispatch,
+      ac.UserEvent({
+        event: "PREF_CHANGED",
+        source: "bar",
+        value: { status: true, menu_source: "CUSTOMIZE_MENU" },
+      })
+    );
+    assert.calledWith(DEFAULT_PROPS.setPref, "foo", true);
+    wrapper.unmount();
+  });
+
+  it("should have data-eventSource attributes on relevent pref changing inputs", () => {
+    wrapper = mount(<ContentSection {...DEFAULT_PROPS} />);
+    assert.equal(
+      wrapper.find("#shortcuts-toggle").prop("data-eventSource"),
+      "TOP_SITES"
+    );
+    assert.equal(
+      wrapper.find("#sponsored-shortcuts").prop("data-eventSource"),
+      "SPONSORED_TOP_SITES"
+    );
+    assert.equal(
+      wrapper.find("#pocket-toggle").prop("data-eventSource"),
+      "TOP_STORIES"
+    );
+    assert.equal(
+      wrapper.find("#sponsored-pocket").prop("data-eventSource"),
+      "POCKET_SPOCS"
+    );
+    assert.equal(
+      wrapper.find("#highlights-toggle").prop("data-eventSource"),
+      "HIGHLIGHTS"
+    );
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamAdmin.test.jsx b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamAdmin.test.jsx
new file mode 100644
index 0000000000..41849fba3e
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamAdmin.test.jsx
@@ -0,0 +1,267 @@
+import {
+  actionCreators as ac,
+  actionTypes as at,
+} from "common/Actions.sys.mjs";
+import {
+  DiscoveryStreamAdminInner,
+  CollapseToggle,
+  DiscoveryStreamAdminUI,
+  Personalization,
+  ToggleStoryButton,
+} from "content-src/components/DiscoveryStreamAdmin/DiscoveryStreamAdmin";
+import React from "react";
+import { shallow } from "enzyme";
+
+describe("DiscoveryStreamAdmin", () => {
+  let sandbox;
+  let wrapper;
+
+  beforeEach(() => {
+    sandbox = sinon.createSandbox();
+    wrapper = shallow(
+      <DiscoveryStreamAdminInner
+        collapsed={false}
+        location={{ routes: [""] }}
+        Prefs={{}}
+      />
+    );
+  });
+  afterEach(() => {
+    sandbox.restore();
+  });
+  it("should render DiscoveryStreamAdmin component", () => {
+    assert.ok(wrapper.exists());
+  });
+  it("should set a .collapsed class on the outer div if props.collapsed is true", () => {
+    wrapper.setProps({ collapsed: true });
+    assert.isTrue(wrapper.find(".discoverystream-admin").hasClass("collapsed"));
+  });
+  it("should set a .expanded class on the outer div if props.collapsed is false", () => {
+    wrapper.setProps({ collapsed: false });
+    assert.isTrue(wrapper.find(".discoverystream-admin").hasClass("expanded"));
+    assert.isFalse(
+      wrapper.find(".discoverystream-admin").hasClass("collapsed")
+    );
+  });
+  it("should render a DS section", () => {
+    assert.equal(wrapper.find("h1").at(0).text(), "Discovery Stream Admin");
+  });
+
+  describe("#DiscoveryStream", () => {
+    let state = {};
+    let dispatch;
+    beforeEach(() => {
+      dispatch = sandbox.stub();
+      state = {
+        config: {
+          enabled: true,
+        },
+        layout: [],
+        spocs: {
+          frequency_caps: [],
+        },
+        feeds: {
+          data: {},
+        },
+      };
+      wrapper = shallow(
+        <DiscoveryStreamAdminUI
+          dispatch={dispatch}
+          otherPrefs={{}}
+          state={{
+            DiscoveryStream: state,
+          }}
+        />
+      );
+    });
+    it("should render a DiscoveryStreamAdminUI component", () => {
+      assert.equal(wrapper.find("h3").at(0).text(), "Layout");
+    });
+    it("should render a spoc in DiscoveryStreamAdminUI component", () => {
+      state.spocs = {
+        frequency_caps: [],
+        data: {
+          spocs: {
+            items: [
+              {
+                id: 12345,
+              },
+            ],
+          },
+        },
+      };
+      wrapper = shallow(
+        <DiscoveryStreamAdminUI
+          otherPrefs={{}}
+          state={{ DiscoveryStream: state }}
+        />
+      );
+      wrapper.instance().onStoryToggle({ id: 12345 });
+      const messageSummary = wrapper.find(".message-summary").at(0);
+      const pre = messageSummary.find("pre").at(0);
+      const spocText = pre.text();
+      assert.equal(spocText, '{\n  "id": 12345\n}');
+    });
+    it("should fire restorePrefDefaults with DISCOVERY_STREAM_CONFIG_RESET_DEFAULTS", () => {
+      wrapper.find("button").at(0).simulate("click");
+      assert.calledWith(
+        dispatch,
+        ac.OnlyToMain({
+          type: at.DISCOVERY_STREAM_CONFIG_RESET_DEFAULTS,
+        })
+      );
+    });
+    it("should fire config change with DISCOVERY_STREAM_CONFIG_CHANGE", () => {
+      wrapper.find("button").at(1).simulate("click");
+      assert.calledWith(
+        dispatch,
+        ac.OnlyToMain({
+          type: at.DISCOVERY_STREAM_CONFIG_CHANGE,
+          data: { enabled: true },
+        })
+      );
+    });
+    it("should fire expireCache with DISCOVERY_STREAM_DEV_EXPIRE_CACHE", () => {
+      wrapper.find("button").at(2).simulate("click");
+      assert.calledWith(
+        dispatch,
+        ac.OnlyToMain({
+          type: at.DISCOVERY_STREAM_DEV_EXPIRE_CACHE,
+        })
+      );
+    });
+    it("should fire systemTick with DISCOVERY_STREAM_DEV_SYSTEM_TICK", () => {
+      wrapper.find("button").at(3).simulate("click");
+      assert.calledWith(
+        dispatch,
+        ac.OnlyToMain({
+          type: at.DISCOVERY_STREAM_DEV_SYSTEM_TICK,
+        })
+      );
+    });
+    it("should fire idleDaily with DISCOVERY_STREAM_DEV_IDLE_DAILY", () => {
+      wrapper.find("button").at(4).simulate("click");
+      assert.calledWith(
+        dispatch,
+        ac.OnlyToMain({
+          type: at.DISCOVERY_STREAM_DEV_IDLE_DAILY,
+        })
+      );
+    });
+    it("should fire syncRemoteSettings with DISCOVERY_STREAM_DEV_SYNC_RS", () => {
+      wrapper.find("button").at(5).simulate("click");
+      assert.calledWith(
+        dispatch,
+        ac.OnlyToMain({
+          type: at.DISCOVERY_STREAM_DEV_SYNC_RS,
+        })
+      );
+    });
+    it("should fire setConfigValue with DISCOVERY_STREAM_CONFIG_SET_VALUE", () => {
+      const name = "name";
+      const value = "value";
+      wrapper.instance().setConfigValue(name, value);
+      assert.calledWith(
+        dispatch,
+        ac.OnlyToMain({
+          type: at.DISCOVERY_STREAM_CONFIG_SET_VALUE,
+          data: { name, value },
+        })
+      );
+    });
+  });
+
+  describe("#Personalization", () => {
+    let dispatch;
+    beforeEach(() => {
+      dispatch = sandbox.stub();
+      wrapper = shallow(
+        <Personalization
+          dispatch={dispatch}
+          state={{
+            Personalization: {
+              lastUpdated: 1000,
+              initialized: true,
+            },
+          }}
+        />
+      );
+    });
+    it("should render with pref checkbox, lastUpdated, and initialized", () => {
+      assert.lengthOf(wrapper.find("TogglePrefCheckbox"), 1);
+      assert.equal(
+        wrapper.find("td").at(1).text(),
+        "Personalization Last Updated"
+      );
+      assert.equal(
+        wrapper.find("td").at(2).text(),
+        new Date(1000).toLocaleString()
+      );
+      assert.equal(
+        wrapper.find("td").at(3).text(),
+        "Personalization Initialized"
+      );
+      assert.equal(wrapper.find("td").at(4).text(), "true");
+    });
+    it("should render with no data with no last updated", () => {
+      wrapper = shallow(
+        <Personalization
+          dispatch={dispatch}
+          state={{
+            Personalization: {
+              version: 2,
+              lastUpdated: 0,
+              initialized: true,
+            },
+          }}
+        />
+      );
+      assert.equal(wrapper.find("td").at(2).text(), "(no data)");
+    });
+    it("should dispatch DISCOVERY_STREAM_PERSONALIZATION_TOGGLE", () => {
+      wrapper.instance().togglePersonalization();
+      assert.calledWith(
+        dispatch,
+        ac.OnlyToMain({
+          type: at.DISCOVERY_STREAM_PERSONALIZATION_TOGGLE,
+        })
+      );
+    });
+  });
+
+  describe("#ToggleStoryButton", () => {
+    it("should fire onClick in toggle button", async () => {
+      let result = "";
+      function onClick(spoc) {
+        result = spoc;
+      }
+
+      wrapper = shallow(<ToggleStoryButton story="spoc" onClick={onClick} />);
+      wrapper.find("button").simulate("click");
+
+      assert.equal(result, "spoc");
+    });
+  });
+});
+
+describe("CollapseToggle", () => {
+  let wrapper;
+  beforeEach(() => {
+    wrapper = shallow(<CollapseToggle location={{ routes: [""] }} />);
+  });
+
+  describe("rendering inner content", () => {
+    it("should not render DiscoveryStreamAdminInner for about:newtab (no hash)", () => {
+      wrapper.setProps({ location: { hash: "", routes: [""] } });
+      assert.lengthOf(wrapper.find(DiscoveryStreamAdminInner), 0);
+    });
+
+    it("should render DiscoveryStreamAdminInner for about:newtab#devtools and subroutes", () => {
+      wrapper.setProps({ location: { hash: "#devtools", routes: [""] } });
+      assert.lengthOf(wrapper.find(DiscoveryStreamAdminInner), 1);
+
+      wrapper.setProps({ location: { hash: "#devtools-foo", routes: [""] } });
+      assert.lengthOf(wrapper.find(DiscoveryStreamAdminInner), 1);
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamBase.test.jsx b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamBase.test.jsx
new file mode 100644
index 0000000000..7720e07327
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamBase.test.jsx
@@ -0,0 +1,313 @@
+import {
+  _DiscoveryStreamBase as DiscoveryStreamBase,
+  isAllowedCSS,
+} from "content-src/components/DiscoveryStreamBase/DiscoveryStreamBase";
+import { GlobalOverrider } from "test/unit/utils";
+import { CardGrid } from "content-src/components/DiscoveryStreamComponents/CardGrid/CardGrid";
+import { CollapsibleSection } from "content-src/components/CollapsibleSection/CollapsibleSection";
+import { DSMessage } from "content-src/components/DiscoveryStreamComponents/DSMessage/DSMessage";
+import { HorizontalRule } from "content-src/components/DiscoveryStreamComponents/HorizontalRule/HorizontalRule";
+import { Navigation } from "content-src/components/DiscoveryStreamComponents/Navigation/Navigation";
+import React from "react";
+import { shallow } from "enzyme";
+import { SectionTitle } from "content-src/components/DiscoveryStreamComponents/SectionTitle/SectionTitle";
+import { TopSites } from "content-src/components/TopSites/TopSites";
+
+describe("<isAllowedCSS>", () => {
+  it("should allow colors", () => {
+    assert.isTrue(isAllowedCSS("color", "red"));
+  });
+
+  it("should allow chrome urls", () => {
+    assert.isTrue(
+      isAllowedCSS(
+        "background-image",
+        `url("chrome://global/skin/icons/info.svg")`
+      )
+    );
+  });
+
+  it("should allow chrome urls", () => {
+    assert.isTrue(
+      isAllowedCSS(
+        "background-image",
+        `url("chrome://browser/skin/history.svg")`
+      )
+    );
+  });
+
+  it("should allow allowed https urls", () => {
+    assert.isTrue(
+      isAllowedCSS(
+        "background-image",
+        `url("https://img-getpocket.cdn.mozilla.net/media/image.png")`
+      )
+    );
+  });
+
+  it("should disallow other https urls", () => {
+    assert.isFalse(
+      isAllowedCSS(
+        "background-image",
+        `url("https://mozilla.org/media/image.png")`
+      )
+    );
+  });
+
+  it("should disallow other protocols", () => {
+    assert.isFalse(
+      isAllowedCSS(
+        "background-image",
+        `url("ftp://mozilla.org/media/image.png")`
+      )
+    );
+  });
+
+  it("should allow allowed multiple valid urls", () => {
+    assert.isTrue(
+      isAllowedCSS(
+        "background-image",
+        `url("https://img-getpocket.cdn.mozilla.net/media/image.png"), url("chrome://browser/skin/history.svg")`
+      )
+    );
+  });
+
+  it("should disallow if any invaild", () => {
+    assert.isFalse(
+      isAllowedCSS(
+        "background-image",
+        `url("chrome://browser/skin/history.svg"), url("ftp://mozilla.org/media/image.png")`
+      )
+    );
+  });
+});
+
+describe("<DiscoveryStreamBase>", () => {
+  let wrapper;
+  let globals;
+  let sandbox;
+
+  function mountComponent(props = {}) {
+    const defaultProps = {
+      config: { collapsible: true },
+      layout: [],
+      feeds: { loaded: true },
+      spocs: {
+        loaded: true,
+        data: { spocs: null },
+      },
+      ...props,
+    };
+    return shallow(
+      <DiscoveryStreamBase
+        locale="en-US"
+        DiscoveryStream={defaultProps}
+        Prefs={{
+          values: {
+            "feeds.section.topstories": true,
+            "feeds.system.topstories": true,
+            "feeds.topsites": true,
+          },
+        }}
+        App={{
+          locale: "en-US",
+        }}
+        document={{
+          documentElement: { lang: "en-US" },
+        }}
+        Sections={[
+          {
+            id: "topstories",
+            learnMore: { link: {} },
+            pref: {},
+          },
+        ]}
+      />
+    );
+  }
+
+  beforeEach(() => {
+    globals = new GlobalOverrider();
+    sandbox = sinon.createSandbox();
+    wrapper = mountComponent();
+  });
+
+  afterEach(() => {
+    sandbox.restore();
+    globals.restore();
+  });
+
+  it("should render something if spocs are not loaded", () => {
+    wrapper = mountComponent({
+      spocs: { loaded: false, data: { spocs: null } },
+    });
+
+    assert.notEqual(wrapper.type(), null);
+  });
+
+  it("should render something if feeds are not loaded", () => {
+    wrapper = mountComponent({ feeds: { loaded: false } });
+
+    assert.notEqual(wrapper.type(), null);
+  });
+
+  it("should render nothing with no layout", () => {
+    assert.ok(wrapper.exists());
+    assert.isEmpty(wrapper.children());
+  });
+
+  it("should render a HorizontalRule component", () => {
+    wrapper = mountComponent({
+      layout: [{ components: [{ type: "HorizontalRule" }] }],
+    });
+
+    assert.equal(
+      wrapper.find(".ds-column-grid div").children().at(0).type(),
+      HorizontalRule
+    );
+  });
+
+  it("should render a CardGrid component", () => {
+    wrapper = mountComponent({
+      layout: [{ components: [{ properties: {}, type: "CardGrid" }] }],
+    });
+
+    assert.equal(
+      wrapper.find(".ds-column-grid div").children().at(0).type(),
+      CardGrid
+    );
+  });
+
+  it("should render a Navigation component", () => {
+    wrapper = mountComponent({
+      layout: [{ components: [{ properties: {}, type: "Navigation" }] }],
+    });
+
+    assert.equal(
+      wrapper.find(".ds-column-grid div").children().at(0).type(),
+      Navigation
+    );
+  });
+
+  it("should render nothing if there was only a Message", () => {
+    wrapper = mountComponent({
+      layout: [
+        { components: [{ header: {}, properties: {}, type: "Message" }] },
+      ],
+    });
+
+    assert.isEmpty(wrapper.children());
+  });
+
+  it("should render a regular Message when not collapsible", () => {
+    wrapper = mountComponent({
+      config: { collapsible: false },
+      layout: [
+        { components: [{ header: {}, properties: {}, type: "Message" }] },
+      ],
+    });
+
+    assert.equal(
+      wrapper.find(".ds-column-grid div").children().at(0).type(),
+      DSMessage
+    );
+  });
+
+  it("should convert first Message component to CollapsibleSection", () => {
+    wrapper = mountComponent({
+      layout: [
+        {
+          components: [
+            { header: {}, properties: {}, type: "Message" },
+            { type: "HorizontalRule" },
+          ],
+        },
+      ],
+    });
+
+    assert.equal(wrapper.children().at(0).type(), CollapsibleSection);
+    assert.equal(wrapper.children().at(0).props().eventSource, "CARDGRID");
+  });
+
+  it("should render a Message component", () => {
+    wrapper = mountComponent({
+      layout: [
+        {
+          components: [
+            { header: {}, type: "Message" },
+            { properties: {}, type: "Message" },
+          ],
+        },
+      ],
+    });
+
+    assert.equal(
+      wrapper.find(".ds-column-grid div").children().at(0).type(),
+      DSMessage
+    );
+  });
+
+  it("should render a SectionTitle component", () => {
+    wrapper = mountComponent({
+      layout: [{ components: [{ properties: {}, type: "SectionTitle" }] }],
+    });
+
+    assert.equal(
+      wrapper.find(".ds-column-grid div").children().at(0).type(),
+      SectionTitle
+    );
+  });
+
+  it("should render TopSites", () => {
+    wrapper = mountComponent({
+      layout: [{ components: [{ properties: {}, type: "TopSites" }] }],
+    });
+
+    assert.equal(
+      wrapper
+        .find(".ds-column-grid div")
+        .find(".ds-top-sites")
+        .children()
+        .at(0)
+        .type(),
+      TopSites
+    );
+  });
+
+  describe("#onStyleMount", () => {
+    let parseStub;
+
+    beforeEach(() => {
+      parseStub = sandbox.stub();
+      globals.set("JSON", { parse: parseStub });
+    });
+
+    afterEach(() => {
+      sandbox.restore();
+      globals.restore();
+    });
+
+    it("should return if no style", () => {
+      assert.isUndefined(wrapper.instance().onStyleMount());
+      assert.notCalled(parseStub);
+    });
+
+    it("should insert rules", () => {
+      const sheetStub = { insertRule: sandbox.stub(), cssRules: [{}] };
+      parseStub.returns([
+        [
+          null,
+          {
+            ".ds-message": "margin-bottom: -20px",
+          },
+          null,
+          null,
+        ],
+      ]);
+      wrapper.instance().onStyleMount({ sheet: sheetStub, dataset: {} });
+
+      assert.calledOnce(sheetStub.insertRule);
+      assert.calledWithExactly(sheetStub.insertRule, "DUMMY#CSS.SELECTOR {}");
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/CardGrid.test.jsx b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/CardGrid.test.jsx
new file mode 100644
index 0000000000..418a731ba1
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/CardGrid.test.jsx
@@ -0,0 +1,354 @@
+import {
+  _CardGrid as CardGrid,
+  IntersectionObserver,
+  RecentSavesContainer,
+  OnboardingExperience,
+  DSSubHeader,
+} from "content-src/components/DiscoveryStreamComponents/CardGrid/CardGrid";
+import { combineReducers, createStore } from "redux";
+import { INITIAL_STATE, reducers } from "common/Reducers.sys.mjs";
+import { Provider } from "react-redux";
+import {
+  DSCard,
+  PlaceholderDSCard,
+} from "content-src/components/DiscoveryStreamComponents/DSCard/DSCard";
+import { TopicsWidget } from "content-src/components/DiscoveryStreamComponents/TopicsWidget/TopicsWidget";
+import {
+  actionCreators as ac,
+  actionTypes as at,
+} from "common/Actions.sys.mjs";
+import React from "react";
+import { shallow, mount } from "enzyme";
+
+// Wrap this around any component that uses useSelector,
+// or any mount that uses a child that uses redux.
+function WrapWithProvider({ children, state = INITIAL_STATE }) {
+  let store = createStore(combineReducers(reducers), state);
+  return <Provider store={store}>{children}</Provider>;
+}
+
+describe("<CardGrid>", () => {
+  let wrapper;
+
+  beforeEach(() => {
+    wrapper = shallow(
+      <CardGrid
+        Prefs={INITIAL_STATE.Prefs}
+        DiscoveryStream={INITIAL_STATE.DiscoveryStream}
+      />
+    );
+  });
+
+  it("should render an empty div", () => {
+    assert.ok(wrapper.exists());
+    assert.lengthOf(wrapper.children(), 0);
+  });
+
+  it("should render DSCards", () => {
+    wrapper.setProps({ items: 2, data: { recommendations: [{}, {}] } });
+
+    assert.lengthOf(wrapper.find(".ds-card-grid").children(), 2);
+    assert.equal(wrapper.find(".ds-card-grid").children().at(0).type(), DSCard);
+  });
+
+  it("should add 4 card classname to card grid", () => {
+    wrapper.setProps({
+      fourCardLayout: true,
+      data: { recommendations: [{}, {}] },
+    });
+
+    assert.ok(wrapper.find(".ds-card-grid-four-card-variant").exists());
+  });
+
+  it("should add no description classname to card grid", () => {
+    wrapper.setProps({
+      hideCardBackground: true,
+      data: { recommendations: [{}, {}] },
+    });
+
+    assert.ok(wrapper.find(".ds-card-grid-hide-background").exists());
+  });
+
+  it("should render sub header in the middle of the card grid for both regular and compact", () => {
+    const commonProps = {
+      essentialReadsHeader: true,
+      editorsPicksHeader: true,
+      items: 12,
+      data: {
+        recommendations: [{}, {}, {}, {}, {}, {}, {}, {}, {}, {}, {}, {}],
+      },
+      Prefs: INITIAL_STATE.Prefs,
+      DiscoveryStream: INITIAL_STATE.DiscoveryStream,
+    };
+    wrapper = mount(
+      <WrapWithProvider>
+        <CardGrid {...commonProps} />
+      </WrapWithProvider>
+    );
+
+    assert.ok(wrapper.find(DSSubHeader).exists());
+
+    wrapper.setProps({
+      compact: true,
+    });
+    wrapper = mount(
+      <WrapWithProvider>
+        <CardGrid {...commonProps} compact={true} />
+      </WrapWithProvider>
+    );
+
+    assert.ok(wrapper.find(DSSubHeader).exists());
+  });
+
+  it("should add/hide description classname to card grid", () => {
+    wrapper.setProps({
+      data: { recommendations: [{}, {}] },
+    });
+
+    assert.ok(wrapper.find(".ds-card-grid-include-descriptions").exists());
+
+    wrapper.setProps({
+      hideDescriptions: true,
+      data: { recommendations: [{}, {}] },
+    });
+
+    assert.ok(!wrapper.find(".ds-card-grid-include-descriptions").exists());
+  });
+
+  it("should create a widget card", () => {
+    wrapper.setProps({
+      widgets: {
+        positions: [{ index: 1 }],
+        data: [{ type: "TopicsWidget" }],
+      },
+      data: {
+        recommendations: [{}, {}, {}],
+      },
+    });
+
+    assert.ok(wrapper.find(TopicsWidget).exists());
+  });
+});
+
+// Build IntersectionObserver class with the arg `entries` for the intersect callback.
+function buildIntersectionObserver(entries) {
+  return class {
+    constructor(callback) {
+      this.callback = callback;
+    }
+
+    observe() {
+      this.callback(entries);
+    }
+
+    unobserve() {}
+
+    disconnect() {}
+  };
+}
+
+describe("<IntersectionObserver>", () => {
+  let wrapper;
+  let fakeWindow;
+  let intersectEntries;
+
+  beforeEach(() => {
+    intersectEntries = [{ isIntersecting: true }];
+    fakeWindow = {
+      IntersectionObserver: buildIntersectionObserver(intersectEntries),
+    };
+    wrapper = mount(<IntersectionObserver windowObj={fakeWindow} />);
+  });
+
+  it("should render an empty div", () => {
+    assert.ok(wrapper.exists());
+    assert.equal(wrapper.children().at(0).type(), "div");
+  });
+
+  it("should fire onIntersecting", () => {
+    const onIntersecting = sinon.stub();
+    wrapper = mount(
+      <IntersectionObserver
+        windowObj={fakeWindow}
+        onIntersecting={onIntersecting}
+      />
+    );
+    assert.calledOnce(onIntersecting);
+  });
+});
+
+describe("<RecentSavesContainer>", () => {
+  let wrapper;
+  let fakeWindow;
+  let intersectEntries;
+  let dispatch;
+
+  beforeEach(() => {
+    dispatch = sinon.stub();
+    intersectEntries = [{ isIntersecting: true }];
+    fakeWindow = {
+      IntersectionObserver: buildIntersectionObserver(intersectEntries),
+    };
+    wrapper = mount(
+      <WrapWithProvider
+        state={{
+          DiscoveryStream: {
+            isUserLoggedIn: true,
+            recentSavesData: [
+              {
+                resolved_id: "resolved_id",
+                top_image_url: "top_image_url",
+                title: "title",
+                resolved_url: "https://resolved_url",
+                domain: "domain",
+                excerpt: "excerpt",
+              },
+            ],
+            experimentData: {
+              utmSource: "utmSource",
+              utmContent: "utmContent",
+              utmCampaign: "utmCampaign",
+            },
+          },
+        }}
+      >
+        <RecentSavesContainer
+          gridClassName="ds-card-grid"
+          windowObj={fakeWindow}
+          dispatch={dispatch}
+        />
+      </WrapWithProvider>
+    ).find(RecentSavesContainer);
+  });
+
+  it("should render an IntersectionObserver when not visible", () => {
+    intersectEntries = [{ isIntersecting: false }];
+    fakeWindow = {
+      IntersectionObserver: buildIntersectionObserver(intersectEntries),
+    };
+    wrapper = mount(
+      <WrapWithProvider>
+        <RecentSavesContainer windowObj={fakeWindow} dispatch={dispatch} />
+      </WrapWithProvider>
+    ).find(RecentSavesContainer);
+
+    assert.ok(wrapper.exists());
+    assert.ok(wrapper.find(IntersectionObserver).exists());
+  });
+
+  it("should render nothing if visible until we log in", () => {
+    assert.ok(!wrapper.find(IntersectionObserver).exists());
+    assert.calledOnce(dispatch);
+    assert.calledWith(
+      dispatch,
+      ac.AlsoToMain({
+        type: at.DISCOVERY_STREAM_POCKET_STATE_INIT,
+      })
+    );
+  });
+
+  it("should render a grid if visible and logged in", () => {
+    assert.lengthOf(wrapper.find(".ds-card-grid"), 1);
+    assert.lengthOf(wrapper.find(DSSubHeader), 1);
+    assert.lengthOf(wrapper.find(PlaceholderDSCard), 2);
+    assert.lengthOf(wrapper.find(DSCard), 3);
+  });
+
+  it("should render a my list link with proper utm params", () => {
+    assert.equal(
+      wrapper.find(".section-sub-link").at(0).prop("url"),
+      "https://getpocket.com/a?utm_source=utmSource&utm_content=utmContent&utm_campaign=utmCampaign"
+    );
+  });
+
+  it("should fire a UserEvent for my list clicks", () => {
+    wrapper.find(".section-sub-link").at(0).simulate("click");
+    assert.calledWith(
+      dispatch,
+      ac.DiscoveryStreamUserEvent({
+        event: "CLICK",
+        source: `CARDGRID_RECENT_SAVES_VIEW_LIST`,
+      })
+    );
+  });
+});
+
+describe("<OnboardingExperience>", () => {
+  let wrapper;
+  let fakeWindow;
+  let intersectEntries;
+  let dispatch;
+  let resizeCallback;
+
+  let fakeResizeObserver = class {
+    constructor(callback) {
+      resizeCallback = callback;
+    }
+
+    observe() {}
+
+    unobserve() {}
+
+    disconnect() {}
+  };
+
+  beforeEach(() => {
+    dispatch = sinon.stub();
+    intersectEntries = [{ isIntersecting: true, intersectionRatio: 1 }];
+    fakeWindow = {
+      ResizeObserver: fakeResizeObserver,
+      IntersectionObserver: buildIntersectionObserver(intersectEntries),
+      document: {
+        visibilityState: "visible",
+        addEventListener: () => {},
+        removeEventListener: () => {},
+      },
+    };
+    wrapper = mount(
+      <WrapWithProvider state={{}}>
+        <OnboardingExperience windowObj={fakeWindow} dispatch={dispatch} />
+      </WrapWithProvider>
+    ).find(OnboardingExperience);
+  });
+
+  it("should render a ds-onboarding", () => {
+    assert.ok(wrapper.exists());
+    assert.lengthOf(wrapper.find(".ds-onboarding"), 1);
+  });
+
+  it("should dismiss on dismiss click", () => {
+    wrapper.find(".ds-dismiss-button").simulate("click");
+
+    assert.calledWith(
+      dispatch,
+      ac.DiscoveryStreamUserEvent({
+        event: "BLOCK",
+        source: "POCKET_ONBOARDING",
+      })
+    );
+    assert.calledWith(
+      dispatch,
+      ac.SetPref("discoverystream.onboardingExperience.dismissed", true)
+    );
+    assert.equal(wrapper.getDOMNode().style["max-height"], "0px");
+    assert.equal(wrapper.getDOMNode().style.opacity, "0");
+  });
+
+  it("should update max-height on resize", () => {
+    sinon
+      .stub(wrapper.find(".ds-onboarding-ref").getDOMNode(), "offsetHeight")
+      .get(() => 123);
+    resizeCallback();
+    assert.equal(wrapper.getDOMNode().style["max-height"], "123px");
+  });
+
+  it("should fire intersection events", () => {
+    assert.calledWith(
+      dispatch,
+      ac.DiscoveryStreamUserEvent({
+        event: "IMPRESSION",
+        source: "POCKET_ONBOARDING",
+      })
+    );
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/CollectionCardGrid.test.jsx b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/CollectionCardGrid.test.jsx
new file mode 100644
index 0000000000..10b06cab9d
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/CollectionCardGrid.test.jsx
@@ -0,0 +1,138 @@
+import { CollectionCardGrid } from "content-src/components/DiscoveryStreamComponents/CollectionCardGrid/CollectionCardGrid";
+import { CardGrid } from "content-src/components/DiscoveryStreamComponents/CardGrid/CardGrid";
+import React from "react";
+import { shallow } from "enzyme";
+
+describe("<CollectionCardGrid>", () => {
+  let wrapper;
+  let sandbox;
+  let dispatchStub;
+  const initialSpocs = [
+    { id: 123, url: "123" },
+    { id: 456, url: "456" },
+    { id: 789, url: "789" },
+  ];
+
+  beforeEach(() => {
+    sandbox = sinon.createSandbox();
+    dispatchStub = sandbox.stub();
+    wrapper = shallow(
+      <CollectionCardGrid
+        dispatch={dispatchStub}
+        type="COLLECTIONCARDGRID"
+        placement={{
+          name: "spocs",
+        }}
+        data={{
+          spocs: initialSpocs,
+        }}
+        spocs={{
+          data: {
+            spocs: {
+              title: "title",
+              context: "context",
+              items: initialSpocs,
+            },
+          },
+        }}
+      />
+    );
+  });
+
+  it("should render an empty div", () => {
+    wrapper = shallow(<CollectionCardGrid />);
+    assert.ok(wrapper.exists());
+    assert.ok(!wrapper.exists(".ds-collection-card-grid"));
+  });
+
+  it("should render a CardGrid", () => {
+    assert.lengthOf(wrapper.find(".ds-collection-card-grid").children(), 1);
+    assert.equal(
+      wrapper.find(".ds-collection-card-grid").children().at(0).type(),
+      CardGrid
+    );
+  });
+
+  it("should inject spocs in every CardGrid rec position", () => {
+    assert.lengthOf(
+      wrapper.find(".ds-collection-card-grid").children().at(0).props().data
+        .recommendations,
+      3
+    );
+  });
+
+  it("should pass along title and context to CardGrid", () => {
+    assert.equal(
+      wrapper.find(".ds-collection-card-grid").children().at(0).props().title,
+      "title"
+    );
+
+    assert.equal(
+      wrapper.find(".ds-collection-card-grid").children().at(0).props().context,
+      "context"
+    );
+  });
+
+  it("should render nothing without a title", () => {
+    wrapper = shallow(
+      <CollectionCardGrid
+        dispatch={dispatchStub}
+        placement={{
+          name: "spocs",
+        }}
+        data={{
+          spocs: initialSpocs,
+        }}
+        spocs={{
+          data: {
+            spocs: {
+              title: "",
+              context: "context",
+              items: initialSpocs,
+            },
+          },
+        }}
+      />
+    );
+
+    assert.ok(wrapper.exists());
+    assert.ok(!wrapper.exists(".ds-collection-card-grid"));
+  });
+
+  it("should dispatch telemety events on dismiss", () => {
+    wrapper.instance().onDismissClick();
+
+    const firstCall = dispatchStub.getCall(0);
+    const secondCall = dispatchStub.getCall(1);
+    const thirdCall = dispatchStub.getCall(2);
+
+    assert.equal(firstCall.args[0].type, "BLOCK_URL");
+    let expected = ["123", "456", "789"].map(url => ({
+      url,
+      pocket_id: undefined,
+      isSponsoredTopSite: undefined,
+      position: 0,
+      is_pocket_card: false,
+    }));
+
+    assert.deepEqual(firstCall.args[0].data, expected);
+
+    assert.equal(secondCall.args[0].type, "DISCOVERY_STREAM_USER_EVENT");
+    assert.deepEqual(secondCall.args[0].data, {
+      event: "BLOCK",
+      source: "COLLECTIONCARDGRID",
+      action_position: 0,
+    });
+
+    assert.equal(thirdCall.args[0].type, "TELEMETRY_IMPRESSION_STATS");
+    assert.deepEqual(thirdCall.args[0].data, {
+      source: "COLLECTIONCARDGRID",
+      block: 0,
+      tiles: [
+        { id: 123, pos: 0 },
+        { id: 456, pos: 1 },
+        { id: 789, pos: 2 },
+      ],
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSCard.test.jsx b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSCard.test.jsx
new file mode 100644
index 0000000000..dad4d19fa5
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSCard.test.jsx
@@ -0,0 +1,582 @@
+import {
+  _DSCard as DSCard,
+  readTimeFromWordCount,
+  DSSource,
+  DefaultMeta,
+  PlaceholderDSCard,
+} from "content-src/components/DiscoveryStreamComponents/DSCard/DSCard";
+import {
+  DSContextFooter,
+  StatusMessage,
+  SponsorLabel,
+} from "content-src/components/DiscoveryStreamComponents/DSContextFooter/DSContextFooter";
+import {
+  actionCreators as ac,
+  actionTypes as at,
+} from "common/Actions.sys.mjs";
+import { DSLinkMenu } from "content-src/components/DiscoveryStreamComponents/DSLinkMenu/DSLinkMenu";
+import React from "react";
+import { INITIAL_STATE } from "common/Reducers.sys.mjs";
+import { SafeAnchor } from "content-src/components/DiscoveryStreamComponents/SafeAnchor/SafeAnchor";
+import { shallow, mount } from "enzyme";
+import { FluentOrText } from "content-src/components/FluentOrText/FluentOrText";
+
+const DEFAULT_PROPS = {
+  url: "about:robots",
+  title: "title",
+  App: {
+    isForStartupCache: false,
+  },
+  DiscoveryStream: INITIAL_STATE.DiscoveryStream,
+};
+
+describe("<DSCard>", () => {
+  let wrapper;
+  let sandbox;
+  let dispatch;
+
+  beforeEach(() => {
+    sandbox = sinon.createSandbox();
+    dispatch = sandbox.stub();
+    wrapper = shallow(<DSCard dispatch={dispatch} {...DEFAULT_PROPS} />);
+    wrapper.setState({ isSeen: true });
+  });
+
+  afterEach(() => {
+    sandbox.restore();
+  });
+
+  it("should render", () => {
+    assert.ok(wrapper.exists());
+    assert.ok(wrapper.find(".ds-card"));
+  });
+
+  it("should render a SafeAnchor", () => {
+    wrapper.setProps({ url: "https://foo.com" });
+
+    assert.equal(wrapper.children().at(0).type(), SafeAnchor);
+    assert.propertyVal(
+      wrapper.children().at(0).props(),
+      "url",
+      "https://foo.com"
+    );
+  });
+
+  it("should pass onLinkClick prop", () => {
+    assert.propertyVal(
+      wrapper.children().at(0).props(),
+      "onLinkClick",
+      wrapper.instance().onLinkClick
+    );
+  });
+
+  it("should render DSLinkMenu", () => {
+    assert.equal(wrapper.children().at(1).type(), DSLinkMenu);
+  });
+
+  it("should start with no .active class", () => {
+    assert.equal(wrapper.find(".active").length, 0);
+  });
+
+  it("should render badges for pocket, bookmark when not a spoc element ", () => {
+    wrapper = mount(<DSCard context_type="bookmark" {...DEFAULT_PROPS} />);
+    wrapper.setState({ isSeen: true });
+    const contextFooter = wrapper.find(DSContextFooter);
+
+    assert.lengthOf(contextFooter.find(StatusMessage), 1);
+  });
+
+  it("should render Sponsored Context for a spoc element", () => {
+    const context = "Sponsored by Foo";
+    wrapper = mount(
+      <DSCard context_type="bookmark" context={context} {...DEFAULT_PROPS} />
+    );
+    wrapper.setState({ isSeen: true });
+    const contextFooter = wrapper.find(DSContextFooter);
+
+    assert.lengthOf(contextFooter.find(StatusMessage), 0);
+    assert.equal(contextFooter.find(".story-sponsored-label").text(), context);
+  });
+
+  it("should render time to read", () => {
+    const discoveryStream = {
+      ...INITIAL_STATE.DiscoveryStream,
+      readTime: true,
+    };
+    wrapper = mount(
+      <DSCard
+        time_to_read={4}
+        {...DEFAULT_PROPS}
+        DiscoveryStream={discoveryStream}
+      />
+    );
+    wrapper.setState({ isSeen: true });
+    const defaultMeta = wrapper.find(DefaultMeta);
+    assert.lengthOf(defaultMeta, 1);
+    assert.equal(defaultMeta.props().timeToRead, 4);
+  });
+
+  it("should not show save to pocket button for spocs", () => {
+    wrapper.setProps({
+      id: "fooidx",
+      pos: 1,
+      type: "foo",
+      flightId: 12345,
+      saveToPocketCard: true,
+    });
+
+    let stpButton = wrapper.find(".card-stp-button");
+
+    assert.lengthOf(stpButton, 0);
+  });
+
+  it("should show save to pocket button for non-spocs", () => {
+    wrapper.setProps({
+      id: "fooidx",
+      pos: 1,
+      type: "foo",
+      saveToPocketCard: true,
+    });
+
+    let stpButton = wrapper.find(".card-stp-button");
+
+    assert.lengthOf(stpButton, 1);
+  });
+
+  describe("onLinkClick", () => {
+    let fakeWindow;
+
+    beforeEach(() => {
+      fakeWindow = {
+        requestIdleCallback: sinon.stub().returns(1),
+        cancelIdleCallback: sinon.stub(),
+        innerWidth: 1000,
+        innerHeight: 900,
+      };
+      wrapper = mount(
+        <DSCard {...DEFAULT_PROPS} dispatch={dispatch} windowObj={fakeWindow} />
+      );
+    });
+
+    it("should call dispatch with the correct events", () => {
+      wrapper.setProps({ id: "fooidx", pos: 1, type: "foo" });
+
+      wrapper.instance().onLinkClick();
+
+      assert.calledTwice(dispatch);
+      assert.calledWith(
+        dispatch,
+        ac.DiscoveryStreamUserEvent({
+          event: "CLICK",
+          source: "FOO",
+          action_position: 1,
+          value: {
+            card_type: "organic",
+            recommendation_id: undefined,
+            tile_id: "fooidx",
+          },
+        })
+      );
+      assert.calledWith(
+        dispatch,
+        ac.ImpressionStats({
+          click: 0,
+          source: "FOO",
+          tiles: [
+            {
+              id: "fooidx",
+              pos: 1,
+              type: "organic",
+              recommendation_id: undefined,
+            },
+          ],
+          window_inner_width: 1000,
+          window_inner_height: 900,
+        })
+      );
+    });
+
+    it("should set the right card_type on spocs", () => {
+      wrapper.setProps({ id: "fooidx", pos: 1, type: "foo", flightId: 12345 });
+
+      wrapper.instance().onLinkClick();
+
+      assert.calledTwice(dispatch);
+      assert.calledWith(
+        dispatch,
+        ac.DiscoveryStreamUserEvent({
+          event: "CLICK",
+          source: "FOO",
+          action_position: 1,
+          value: {
+            card_type: "spoc",
+            recommendation_id: undefined,
+            tile_id: "fooidx",
+          },
+        })
+      );
+      assert.calledWith(
+        dispatch,
+        ac.ImpressionStats({
+          click: 0,
+          source: "FOO",
+          tiles: [
+            {
+              id: "fooidx",
+              pos: 1,
+              type: "spoc",
+              recommendation_id: undefined,
+            },
+          ],
+          window_inner_width: 1000,
+          window_inner_height: 900,
+        })
+      );
+    });
+
+    it("should call dispatch with a shim", () => {
+      wrapper.setProps({
+        id: "fooidx",
+        pos: 1,
+        type: "foo",
+        shim: {
+          click: "click shim",
+        },
+      });
+
+      wrapper.instance().onLinkClick();
+
+      assert.calledTwice(dispatch);
+      assert.calledWith(
+        dispatch,
+        ac.DiscoveryStreamUserEvent({
+          event: "CLICK",
+          source: "FOO",
+          action_position: 1,
+          value: {
+            card_type: "organic",
+            recommendation_id: undefined,
+            tile_id: "fooidx",
+            shim: "click shim",
+          },
+        })
+      );
+      assert.calledWith(
+        dispatch,
+        ac.ImpressionStats({
+          click: 0,
+          source: "FOO",
+          tiles: [
+            {
+              id: "fooidx",
+              pos: 1,
+              shim: "click shim",
+              type: "organic",
+              recommendation_id: undefined,
+            },
+          ],
+          window_inner_width: 1000,
+          window_inner_height: 900,
+        })
+      );
+    });
+  });
+
+  describe("DSCard with CTA", () => {
+    beforeEach(() => {
+      wrapper = mount(<DSCard {...DEFAULT_PROPS} />);
+      wrapper.setState({ isSeen: true });
+    });
+
+    it("should render Default Meta", () => {
+      const default_meta = wrapper.find(DefaultMeta);
+      assert.ok(default_meta.exists());
+    });
+  });
+
+  describe("DSCard with Intersection Observer", () => {
+    beforeEach(() => {
+      wrapper = shallow(<DSCard {...DEFAULT_PROPS} />);
+    });
+
+    it("should render card when seen", () => {
+      let card = wrapper.find("div.ds-card.placeholder");
+      assert.lengthOf(card, 1);
+
+      wrapper.instance().observer = {
+        unobserve: sandbox.stub(),
+      };
+      wrapper.instance().placeholderElement = "element";
+
+      wrapper.instance().onSeen([
+        {
+          isIntersecting: true,
+        },
+      ]);
+
+      assert.isTrue(wrapper.instance().state.isSeen);
+      card = wrapper.find("div.ds-card.placeholder");
+      assert.lengthOf(card, 0);
+      assert.lengthOf(wrapper.find(SafeAnchor), 1);
+      assert.calledOnce(wrapper.instance().observer.unobserve);
+      assert.calledWith(wrapper.instance().observer.unobserve, "element");
+    });
+
+    it("should setup proper placholder ref for isSeen", () => {
+      wrapper.instance().setPlaceholderRef("element");
+      assert.equal(wrapper.instance().placeholderElement, "element");
+    });
+
+    it("should setup observer on componentDidMount", () => {
+      wrapper = mount(<DSCard {...DEFAULT_PROPS} />);
+      assert.isTrue(!!wrapper.instance().observer);
+    });
+  });
+
+  describe("DSCard with Idle Callback", () => {
+    let windowStub = {
+      requestIdleCallback: sinon.stub().returns(1),
+      cancelIdleCallback: sinon.stub(),
+    };
+    beforeEach(() => {
+      wrapper = shallow(<DSCard windowObj={windowStub} {...DEFAULT_PROPS} />);
+    });
+
+    it("should call requestIdleCallback on componentDidMount", () => {
+      assert.calledOnce(windowStub.requestIdleCallback);
+    });
+
+    it("should call cancelIdleCallback on componentWillUnmount", () => {
+      wrapper.instance().componentWillUnmount();
+      assert.calledOnce(windowStub.cancelIdleCallback);
+    });
+  });
+
+  describe("DSCard when rendered for about:home startup cache", () => {
+    beforeEach(() => {
+      const props = {
+        App: {
+          isForStartupCache: true,
+        },
+        DiscoveryStream: INITIAL_STATE.DiscoveryStream,
+      };
+      wrapper = mount(<DSCard {...props} />);
+    });
+
+    it("should be set as isSeen automatically", () => {
+      assert.isTrue(wrapper.instance().state.isSeen);
+    });
+  });
+
+  describe("DSCard onSaveClick", () => {
+    it("should fire telemetry for onSaveClick", () => {
+      wrapper.setProps({ id: "fooidx", pos: 1, type: "foo" });
+      wrapper.instance().onSaveClick();
+
+      assert.calledThrice(dispatch);
+      assert.calledWith(
+        dispatch,
+        ac.AlsoToMain({
+          type: at.SAVE_TO_POCKET,
+          data: { site: { url: "about:robots", title: "title" } },
+        })
+      );
+      assert.calledWith(
+        dispatch,
+        ac.DiscoveryStreamUserEvent({
+          event: "SAVE_TO_POCKET",
+          source: "CARDGRID_HOVER",
+          action_position: 1,
+          value: {
+            card_type: "organic",
+            recommendation_id: undefined,
+            tile_id: "fooidx",
+          },
+        })
+      );
+      assert.calledWith(
+        dispatch,
+        ac.ImpressionStats({
+          source: "CARDGRID_HOVER",
+          pocket: 0,
+          tiles: [
+            {
+              id: "fooidx",
+              pos: 1,
+              recommendation_id: undefined,
+            },
+          ],
+        })
+      );
+    });
+  });
+
+  describe("DSCard menu open states", () => {
+    let cardNode;
+    let fakeDocument;
+    let fakeWindow;
+
+    beforeEach(() => {
+      fakeDocument = { l10n: { translateFragment: sinon.stub() } };
+      fakeWindow = {
+        document: fakeDocument,
+        requestIdleCallback: sinon.stub().returns(1),
+        cancelIdleCallback: sinon.stub(),
+      };
+      wrapper = mount(<DSCard {...DEFAULT_PROPS} windowObj={fakeWindow} />);
+      wrapper.setState({ isSeen: true });
+      cardNode = wrapper.getDOMNode();
+    });
+
+    it("Should remove active on Menu Update", () => {
+      // Add active class name to DSCard wrapper
+      // to simulate menu open state
+      cardNode.classList.add("active");
+      assert.equal(
+        cardNode.className,
+        "ds-card ds-card-title-lines-3 ds-card-desc-lines-3 active"
+      );
+
+      wrapper.instance().onMenuUpdate(false);
+      wrapper.update();
+
+      assert.equal(
+        cardNode.className,
+        "ds-card ds-card-title-lines-3 ds-card-desc-lines-3"
+      );
+    });
+
+    it("Should add active on Menu Show", async () => {
+      await wrapper.instance().onMenuShow();
+      wrapper.update();
+      assert.equal(
+        cardNode.className,
+        "ds-card ds-card-title-lines-3 ds-card-desc-lines-3 active"
+      );
+    });
+
+    it("Should add last-item to support resized window", async () => {
+      fakeWindow.scrollMaxX = 20;
+      await wrapper.instance().onMenuShow();
+      wrapper.update();
+      assert.equal(
+        cardNode.className,
+        "ds-card ds-card-title-lines-3 ds-card-desc-lines-3 last-item active"
+      );
+    });
+
+    it("should remove .active and .last-item classes", () => {
+      const instance = wrapper.instance();
+      const remove = sinon.stub();
+      instance.contextMenuButtonHostElement = {
+        classList: { remove },
+      };
+      instance.onMenuUpdate();
+      assert.calledOnce(remove);
+    });
+
+    it("should add .active and .last-item classes", async () => {
+      const instance = wrapper.instance();
+      const add = sinon.stub();
+      instance.contextMenuButtonHostElement = {
+        classList: { add },
+      };
+      await instance.onMenuShow();
+      assert.calledOnce(add);
+    });
+  });
+});
+
+describe("<PlaceholderDSCard> component", () => {
+  it("should have placeholder prop", () => {
+    const wrapper = shallow(<PlaceholderDSCard />);
+    const placeholder = wrapper.prop("placeholder");
+    assert.isTrue(placeholder);
+  });
+
+  it("should contain placeholder div", () => {
+    const wrapper = shallow(<DSCard placeholder={true} {...DEFAULT_PROPS} />);
+    wrapper.setState({ isSeen: true });
+    const card = wrapper.find("div.ds-card.placeholder");
+    assert.lengthOf(card, 1);
+  });
+
+  it("should not be clickable", () => {
+    const wrapper = shallow(<DSCard placeholder={true} {...DEFAULT_PROPS} />);
+    wrapper.setState({ isSeen: true });
+    const anchor = wrapper.find("SafeAnchor.ds-card-link");
+    assert.lengthOf(anchor, 0);
+  });
+
+  it("should not have context menu", () => {
+    const wrapper = shallow(<DSCard placeholder={true} {...DEFAULT_PROPS} />);
+    wrapper.setState({ isSeen: true });
+    const linkMenu = wrapper.find(DSLinkMenu);
+    assert.lengthOf(linkMenu, 0);
+  });
+});
+
+describe("<DSSource> component", () => {
+  it("should return a default source without compact", () => {
+    const wrapper = shallow(<DSSource source="Mozilla" />);
+
+    let sourceElement = wrapper.find(".source");
+    assert.equal(sourceElement.text(), "Mozilla");
+  });
+  it("should return a default source with compact without a sponsor or time to read", () => {
+    const wrapper = shallow(<DSSource compact={true} source="Mozilla" />);
+
+    let sourceElement = wrapper.find(".source");
+    assert.equal(sourceElement.text(), "Mozilla");
+  });
+  it("should return a SponsorLabel with compact and a sponsor", () => {
+    const wrapper = shallow(
+      <DSSource newSponsoredLabel={true} sponsor="Mozilla" />
+    );
+    const sponsorLabel = wrapper.find(SponsorLabel);
+    assert.lengthOf(sponsorLabel, 1);
+  });
+  it("should return a time to read with compact and without a sponsor but with a time to read", () => {
+    const wrapper = shallow(
+      <DSSource compact={true} source="Mozilla" timeToRead="2000" />
+    );
+
+    let timeToRead = wrapper.find(".time-to-read");
+    assert.lengthOf(timeToRead, 1);
+
+    // Weirdly, we can test for the pressence of fluent, because time to read needs to be translated.
+    // This is also because we did a shallow render, that th contents of fluent would be empty anyway.
+    const fluentOrText = wrapper.find(FluentOrText);
+    assert.lengthOf(fluentOrText, 1);
+  });
+  it("should prioritize a SponsorLabel if for some reason it gets everything", () => {
+    const wrapper = shallow(
+      <DSSource
+        newSponsoredLabel={true}
+        sponsor="Mozilla"
+        source="Mozilla"
+        timeToRead="2000"
+      />
+    );
+    const sponsorLabel = wrapper.find(SponsorLabel);
+    assert.lengthOf(sponsorLabel, 1);
+  });
+});
+
+describe("readTimeFromWordCount function", () => {
+  it("should return proper read time", () => {
+    const result = readTimeFromWordCount(2000);
+    assert.equal(result, 10);
+  });
+  it("should return false with falsey word count", () => {
+    assert.isFalse(readTimeFromWordCount());
+    assert.isFalse(readTimeFromWordCount(0));
+    assert.isFalse(readTimeFromWordCount(""));
+    assert.isFalse(readTimeFromWordCount(null));
+    assert.isFalse(readTimeFromWordCount(undefined));
+  });
+  it("should return NaN with invalid word count", () => {
+    assert.isNaN(readTimeFromWordCount("zero"));
+    assert.isNaN(readTimeFromWordCount({}));
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSContextFooter.test.jsx b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSContextFooter.test.jsx
new file mode 100644
index 0000000000..08ac7868ce
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSContextFooter.test.jsx
@@ -0,0 +1,138 @@
+import {
+  DSContextFooter,
+  StatusMessage,
+  DSMessageFooter,
+} from "content-src/components/DiscoveryStreamComponents/DSContextFooter/DSContextFooter";
+import React from "react";
+import { mount } from "enzyme";
+import { cardContextTypes } from "content-src/components/Card/types.js";
+import { FluentOrText } from "content-src/components/FluentOrText/FluentOrText.jsx";
+
+describe("<DSContextFooter>", () => {
+  let wrapper;
+  let sandbox;
+  const bookmarkBadge = "bookmark";
+  const removeBookmarkBadge = "removedBookmark";
+  const context = "Sponsored by Babel";
+  const sponsored_by_override = "Sponsored override";
+  const engagement = "Popular";
+
+  beforeEach(() => {
+    wrapper = mount(<DSContextFooter />);
+    sandbox = sinon.createSandbox();
+  });
+
+  afterEach(() => {
+    sandbox.restore();
+  });
+
+  it("should render", () => assert.isTrue(wrapper.exists()));
+  it("should not render an engagement status if display_engagement_labels is false", () => {
+    wrapper = mount(
+      <DSContextFooter
+        display_engagement_labels={false}
+        engagement={engagement}
+      />
+    );
+
+    const engagementLabel = wrapper.find(".story-view-count");
+    assert.equal(engagementLabel.length, 0);
+  });
+  it("should render a badge if a proper badge prop is passed", () => {
+    wrapper = mount(
+      <DSContextFooter context_type={bookmarkBadge} engagement={engagement} />
+    );
+    const { fluentID } = cardContextTypes[bookmarkBadge];
+
+    assert.lengthOf(wrapper.find(".story-view-count"), 0);
+    const statusLabel = wrapper.find(".story-context-label");
+    assert.equal(statusLabel.prop("data-l10n-id"), fluentID);
+  });
+  it("should only render a sponsored context if pass a sponsored context", async () => {
+    wrapper = mount(
+      <DSContextFooter
+        context_type={bookmarkBadge}
+        context={context}
+        engagement={engagement}
+      />
+    );
+
+    assert.lengthOf(wrapper.find(".story-view-count"), 0);
+    assert.lengthOf(wrapper.find(StatusMessage), 0);
+    assert.equal(wrapper.find(".story-sponsored-label").text(), context);
+  });
+  it("should render a sponsored_by_override if passed a sponsored_by_override", async () => {
+    wrapper = mount(
+      <DSContextFooter
+        context_type={bookmarkBadge}
+        context={context}
+        sponsored_by_override={sponsored_by_override}
+        engagement={engagement}
+      />
+    );
+
+    assert.equal(
+      wrapper.find(".story-sponsored-label").text(),
+      sponsored_by_override
+    );
+  });
+  it("should render nothing with a sponsored_by_override empty string", async () => {
+    wrapper = mount(
+      <DSContextFooter
+        context_type={bookmarkBadge}
+        context={context}
+        sponsored_by_override=""
+        engagement={engagement}
+      />
+    );
+
+    assert.isFalse(wrapper.find(".story-sponsored-label").exists());
+  });
+  it("should render localized string with sponsor with no sponsored_by_override", async () => {
+    wrapper = mount(
+      <DSContextFooter
+        context_type={bookmarkBadge}
+        context={context}
+        sponsor="Nimoy"
+        engagement={engagement}
+      />
+    );
+
+    assert.equal(
+      wrapper.find(".story-sponsored-label").children().at(0).type(),
+      FluentOrText
+    );
+  });
+  it("should render a new badge if props change from an old badge to a new one", async () => {
+    wrapper = mount(<DSContextFooter context_type={bookmarkBadge} />);
+
+    const { fluentID: bookmarkFluentID } = cardContextTypes[bookmarkBadge];
+    const bookmarkStatusMessage = wrapper.find(
+      `div[data-l10n-id='${bookmarkFluentID}']`
+    );
+    assert.isTrue(bookmarkStatusMessage.exists());
+
+    const { fluentID: removeBookmarkFluentID } =
+      cardContextTypes[removeBookmarkBadge];
+
+    wrapper.setProps({ context_type: removeBookmarkBadge });
+    await wrapper.update();
+
+    assert.isEmpty(bookmarkStatusMessage);
+    const removedBookmarkStatusMessage = wrapper.find(
+      `div[data-l10n-id='${removeBookmarkFluentID}']`
+    );
+    assert.isTrue(removedBookmarkStatusMessage.exists());
+  });
+  it("should render a story footer", () => {
+    wrapper = mount(
+      <DSMessageFooter
+        context_type={bookmarkBadge}
+        engagement={engagement}
+        display_engagement_labels={true}
+      />
+    );
+
+    assert.lengthOf(wrapper.find(".story-footer"), 1);
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSDismiss.test.jsx b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSDismiss.test.jsx
new file mode 100644
index 0000000000..2f7e206b4f
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSDismiss.test.jsx
@@ -0,0 +1,51 @@
+import { DSDismiss } from "content-src/components/DiscoveryStreamComponents/DSDismiss/DSDismiss";
+import React from "react";
+import { shallow } from "enzyme";
+
+describe("<DSDismiss>", () => {
+  const fakeSpoc = {
+    url: "https://foo.com",
+    guid: "1234",
+  };
+  let wrapper;
+  let sandbox;
+  let onDismissClickStub;
+
+  beforeEach(() => {
+    sandbox = sinon.createSandbox();
+    onDismissClickStub = sandbox.stub();
+    wrapper = shallow(
+      <DSDismiss
+        data={fakeSpoc}
+        onDismissClick={onDismissClickStub}
+        shouldSendImpressionStats={true}
+      />
+    );
+  });
+
+  afterEach(() => {
+    sandbox.restore();
+  });
+
+  it("should render", () => {
+    assert.ok(wrapper.exists());
+    assert.ok(wrapper.find(".ds-dismiss").exists());
+  });
+
+  it("should render proper hover state", () => {
+    wrapper.instance().onHover();
+    assert.ok(wrapper.find(".hovering").exists());
+    wrapper.instance().offHover();
+    assert.ok(!wrapper.find(".hovering").exists());
+  });
+
+  it("should dispatch call onDismissClick", () => {
+    wrapper.instance().onDismissClick();
+    assert.calledOnce(onDismissClickStub);
+  });
+
+  it("should add extra classes", () => {
+    wrapper = shallow(<DSDismiss extraClasses="extra-class" />);
+    assert.ok(wrapper.find(".extra-class").exists());
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSEmptyState.test.jsx b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSEmptyState.test.jsx
new file mode 100644
index 0000000000..6aa8045299
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSEmptyState.test.jsx
@@ -0,0 +1,73 @@
+import { DSEmptyState } from "content-src/components/DiscoveryStreamComponents/DSEmptyState/DSEmptyState";
+import React from "react";
+import { shallow } from "enzyme";
+
+describe("<DSEmptyState>", () => {
+  let wrapper;
+
+  beforeEach(() => {
+    wrapper = shallow(<DSEmptyState />);
+  });
+
+  it("should render", () => {
+    assert.ok(wrapper.exists());
+    assert.ok(wrapper.find(".section-empty-state").exists());
+  });
+
+  it("should render defaultempty state message", () => {
+    assert.ok(wrapper.find(".empty-state-message").exists());
+    const header = wrapper.find(
+      "h2[data-l10n-id='newtab-discovery-empty-section-topstories-header']"
+    );
+    const paragraph = wrapper.find(
+      "p[data-l10n-id='newtab-discovery-empty-section-topstories-content']"
+    );
+
+    assert.ok(header.exists());
+    assert.ok(paragraph.exists());
+  });
+
+  it("should render failed state message", () => {
+    wrapper = shallow(<DSEmptyState status="failed" />);
+    const button = wrapper.find(
+      "button[data-l10n-id='newtab-discovery-empty-section-topstories-try-again-button']"
+    );
+
+    assert.ok(button.exists());
+  });
+
+  it("should render waiting state message", () => {
+    wrapper = shallow(<DSEmptyState status="waiting" />);
+    const button = wrapper.find(
+      "button[data-l10n-id='newtab-discovery-empty-section-topstories-loading']"
+    );
+
+    assert.ok(button.exists());
+  });
+
+  it("should dispatch DISCOVERY_STREAM_RETRY_FEED on failed state button click", () => {
+    const dispatch = sinon.spy();
+
+    wrapper = shallow(
+      <DSEmptyState
+        status="failed"
+        dispatch={dispatch}
+        feed={{ url: "https://foo.com", data: {} }}
+      />
+    );
+    wrapper.find("button.try-again-button").simulate("click");
+
+    assert.calledTwice(dispatch);
+    let [action] = dispatch.firstCall.args;
+    assert.equal(action.type, "DISCOVERY_STREAM_FEED_UPDATE");
+    assert.deepEqual(action.data.feed, {
+      url: "https://foo.com",
+      data: { status: "waiting" },
+    });
+
+    [action] = dispatch.secondCall.args;
+
+    assert.equal(action.type, "DISCOVERY_STREAM_RETRY_FEED");
+    assert.deepEqual(action.data.feed, { url: "https://foo.com", data: {} });
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSImage.test.jsx b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSImage.test.jsx
new file mode 100644
index 0000000000..bb2ce3b0b3
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSImage.test.jsx
@@ -0,0 +1,146 @@
+import { DSImage } from "content-src/components/DiscoveryStreamComponents/DSImage/DSImage";
+import { mount } from "enzyme";
+import React from "react";
+
+describe("Discovery Stream <DSImage>", () => {
+  it("should have a child with class ds-image", () => {
+    const img = mount(<DSImage />);
+    const child = img.find(".ds-image");
+
+    assert.lengthOf(child, 1);
+  });
+
+  it("should set proper sources if only `source` is available", () => {
+    const img = mount(<DSImage source="https://placekitten.com/g/640/480" />);
+
+    assert.equal(
+      img.find("img").prop("src"),
+      "https://placekitten.com/g/640/480"
+    );
+  });
+
+  it("should set proper sources if `rawSource` is available", () => {
+    const testSizes = [
+      {
+        mediaMatcher: "(min-width: 1122px)",
+        width: 296,
+        height: 148,
+      },
+
+      {
+        mediaMatcher: "(min-width: 866px)",
+        width: 218,
+        height: 109,
+      },
+
+      {
+        mediaMatcher: "(max-width: 610px)",
+        width: 202,
+        height: 101,
+      },
+    ];
+
+    const img = mount(
+      <DSImage
+        rawSource="https://placekitten.com/g/640/480"
+        sizes={testSizes}
+      />
+    );
+
+    assert.equal(
+      img.find("img").prop("src"),
+      "https://placekitten.com/g/640/480"
+    );
+    assert.equal(
+      img.find("img").prop("srcSet"),
+      [
+        "https://img-getpocket.cdn.mozilla.net/296x148/filters:format(jpeg):quality(60):no_upscale():strip_exif()/https%3A%2F%2Fplacekitten.com%2Fg%2F640%2F480 296w",
+        "https://img-getpocket.cdn.mozilla.net/592x296/filters:format(jpeg):quality(60):no_upscale():strip_exif()/https%3A%2F%2Fplacekitten.com%2Fg%2F640%2F480 592w",
+        "https://img-getpocket.cdn.mozilla.net/218x109/filters:format(jpeg):quality(60):no_upscale():strip_exif()/https%3A%2F%2Fplacekitten.com%2Fg%2F640%2F480 218w",
+        "https://img-getpocket.cdn.mozilla.net/436x218/filters:format(jpeg):quality(60):no_upscale():strip_exif()/https%3A%2F%2Fplacekitten.com%2Fg%2F640%2F480 436w",
+        "https://img-getpocket.cdn.mozilla.net/202x101/filters:format(jpeg):quality(60):no_upscale():strip_exif()/https%3A%2F%2Fplacekitten.com%2Fg%2F640%2F480 202w",
+        "https://img-getpocket.cdn.mozilla.net/404x202/filters:format(jpeg):quality(60):no_upscale():strip_exif()/https%3A%2F%2Fplacekitten.com%2Fg%2F640%2F480 404w",
+      ].join(",")
+    );
+  });
+
+  it("should fall back to unoptimized when optimized failed", () => {
+    const img = mount(
+      <DSImage
+        source="https://placekitten.com/g/640/480"
+        rawSource="https://placekitten.com/g/640/480"
+      />
+    );
+    img.setState({
+      isSeen: true,
+      containerWidth: 640,
+      containerHeight: 480,
+    });
+
+    img.instance().onOptimizedImageError();
+    img.update();
+
+    assert.equal(
+      img.find("img").prop("src"),
+      "https://placekitten.com/g/640/480"
+    );
+  });
+
+  it("should render a placeholder image with no source and recent save", () => {
+    const img = mount(<DSImage isRecentSave={true} url="foo" title="bar" />);
+    img.setState({ isSeen: true });
+
+    img.update();
+
+    assert.equal(img.find("div").prop("className"), "placeholder-image");
+  });
+
+  it("should render a broken image with a source and a recent save", () => {
+    const img = mount(<DSImage isRecentSave={true} source="foo" />);
+    img.setState({ isSeen: true });
+
+    img.instance().onNonOptimizedImageError();
+    img.update();
+
+    assert.equal(img.find("div").prop("className"), "broken-image");
+  });
+
+  it("should render a broken image without a source and not a recent save", () => {
+    const img = mount(<DSImage isRecentSave={false} />);
+    img.setState({ isSeen: true });
+
+    img.instance().onNonOptimizedImageError();
+    img.update();
+
+    assert.equal(img.find("div").prop("className"), "broken-image");
+  });
+
+  it("should update loaded state when seen", () => {
+    const img = mount(
+      <DSImage rawSource="https://placekitten.com/g/640/480" />
+    );
+
+    img.instance().onLoad();
+    assert.propertyVal(img.state(), "isLoaded", true);
+  });
+
+  describe("DSImage with Idle Callback", () => {
+    let wrapper;
+    let windowStub = {
+      requestIdleCallback: sinon.stub().returns(1),
+      cancelIdleCallback: sinon.stub(),
+    };
+    beforeEach(() => {
+      wrapper = mount(<DSImage windowObj={windowStub} />);
+    });
+
+    it("should call requestIdleCallback on componentDidMount", () => {
+      assert.calledOnce(windowStub.requestIdleCallback);
+    });
+
+    it("should call cancelIdleCallback on componentWillUnmount", () => {
+      wrapper.instance().componentWillUnmount();
+      assert.calledOnce(windowStub.cancelIdleCallback);
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSLinkMenu.test.jsx b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSLinkMenu.test.jsx
new file mode 100644
index 0000000000..3aa128a32a
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSLinkMenu.test.jsx
@@ -0,0 +1,151 @@
+import { mount, shallow } from "enzyme";
+import { DSLinkMenu } from "content-src/components/DiscoveryStreamComponents/DSLinkMenu/DSLinkMenu";
+import { ContextMenuButton } from "content-src/components/ContextMenu/ContextMenuButton";
+import { LinkMenu } from "content-src/components/LinkMenu/LinkMenu";
+import React from "react";
+
+describe("<DSLinkMenu>", () => {
+  let wrapper;
+
+  describe("DS link menu actions", () => {
+    beforeEach(() => {
+      wrapper = mount(<DSLinkMenu />);
+    });
+
+    afterEach(() => {
+      wrapper.unmount();
+    });
+
+    it("should parse args for fluent correctly ", () => {
+      const title = '"fluent"';
+      wrapper = mount(<DSLinkMenu title={title} />);
+
+      const button = wrapper.find(
+        "button[data-l10n-id='newtab-menu-content-tooltip']"
+      );
+      assert.equal(button.prop("data-l10n-args"), JSON.stringify({ title }));
+    });
+  });
+
+  describe("DS context menu options", () => {
+    const ValidDSLinkMenuProps = {
+      site: {},
+      pocket_button_enabled: true,
+    };
+
+    beforeEach(() => {
+      wrapper = shallow(<DSLinkMenu {...ValidDSLinkMenuProps} />);
+    });
+
+    it("should render a context menu button", () => {
+      assert.ok(wrapper.exists());
+      assert.ok(
+        wrapper.find(ContextMenuButton).exists(),
+        "context menu button exists"
+      );
+    });
+
+    it("should render LinkMenu when context menu button is clicked", () => {
+      let button = wrapper.find(ContextMenuButton);
+      button.simulate("click", { preventDefault: () => {} });
+      assert.equal(wrapper.find(LinkMenu).length, 1);
+    });
+
+    it("should pass dispatch, onShow, site, options, shouldSendImpressionStats, source and index to LinkMenu", () => {
+      wrapper
+        .find(ContextMenuButton)
+        .simulate("click", { preventDefault: () => {} });
+      const linkMenuProps = wrapper.find(LinkMenu).props();
+      [
+        "dispatch",
+        "onShow",
+        "site",
+        "index",
+        "options",
+        "source",
+        "shouldSendImpressionStats",
+      ].forEach(prop => assert.property(linkMenuProps, prop));
+    });
+
+    it("should pass through the correct menu options to LinkMenu", () => {
+      wrapper
+        .find(ContextMenuButton)
+        .simulate("click", { preventDefault: () => {} });
+      const linkMenuProps = wrapper.find(LinkMenu).props();
+      assert.deepEqual(linkMenuProps.options, [
+        "CheckBookmark",
+        "CheckArchiveFromPocket",
+        "CheckSavedToPocket",
+        "Separator",
+        "OpenInNewWindow",
+        "OpenInPrivateWindow",
+        "Separator",
+        "BlockUrl",
+      ]);
+    });
+
+    it("should pass through the correct menu options to LinkMenu for spocs", () => {
+      wrapper = shallow(
+        <DSLinkMenu
+          {...ValidDSLinkMenuProps}
+          flightId="1234"
+          showPrivacyInfo={true}
+        />
+      );
+      wrapper
+        .find(ContextMenuButton)
+        .simulate("click", { preventDefault: () => {} });
+      const linkMenuProps = wrapper.find(LinkMenu).props();
+      assert.deepEqual(linkMenuProps.options, [
+        "CheckBookmark",
+        "CheckArchiveFromPocket",
+        "CheckSavedToPocket",
+        "Separator",
+        "OpenInNewWindow",
+        "OpenInPrivateWindow",
+        "Separator",
+        "BlockUrl",
+        "ShowPrivacyInfo",
+      ]);
+    });
+
+    it("should pass through the correct menu options to LinkMenu for save to Pocket button", () => {
+      wrapper = shallow(
+        <DSLinkMenu {...ValidDSLinkMenuProps} saveToPocketCard={true} />
+      );
+      wrapper
+        .find(ContextMenuButton)
+        .simulate("click", { preventDefault: () => {} });
+      const linkMenuProps = wrapper.find(LinkMenu).props();
+      assert.deepEqual(linkMenuProps.options, [
+        "CheckBookmark",
+        "CheckArchiveFromPocket",
+        "CheckDeleteFromPocket",
+        "Separator",
+        "OpenInNewWindow",
+        "OpenInPrivateWindow",
+        "Separator",
+        "BlockUrl",
+      ]);
+    });
+
+    it("should pass through the correct menu options to LinkMenu if Pocket is disabled", () => {
+      wrapper = shallow(
+        <DSLinkMenu {...ValidDSLinkMenuProps} pocket_button_enabled={false} />
+      );
+      wrapper
+        .find(ContextMenuButton)
+        .simulate("click", { preventDefault: () => {} });
+      const linkMenuProps = wrapper.find(LinkMenu).props();
+      assert.deepEqual(linkMenuProps.options, [
+        "CheckBookmark",
+        "CheckArchiveFromPocket",
+        "Separator",
+        "OpenInNewWindow",
+        "OpenInPrivateWindow",
+        "Separator",
+        "BlockUrl",
+      ]);
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSMessage.test.jsx b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSMessage.test.jsx
new file mode 100644
index 0000000000..7d9f13cc8a
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSMessage.test.jsx
@@ -0,0 +1,57 @@
+import { DSMessage } from "content-src/components/DiscoveryStreamComponents/DSMessage/DSMessage";
+import React from "react";
+import { SafeAnchor } from "content-src/components/DiscoveryStreamComponents/SafeAnchor/SafeAnchor";
+import { FluentOrText } from "content-src/components/FluentOrText/FluentOrText";
+import { mount } from "enzyme";
+
+describe("<DSMessage>", () => {
+  let wrapper;
+
+  beforeEach(() => {
+    wrapper = mount(<DSMessage />);
+  });
+
+  it("should render", () => {
+    assert.ok(wrapper.exists());
+    assert.ok(wrapper.find(".ds-message").exists());
+  });
+
+  it("should render an icon", () => {
+    wrapper.setProps({ icon: "foo" });
+
+    assert.ok(wrapper.find(".glyph").exists());
+    assert.propertyVal(
+      wrapper.find(".glyph").props().style,
+      "backgroundImage",
+      `url(foo)`
+    );
+  });
+
+  it("should render a title", () => {
+    wrapper.setProps({ title: "foo" });
+
+    assert.ok(wrapper.find(".title-text").exists());
+    assert.equal(wrapper.find(".title-text").text(), "foo");
+  });
+
+  it("should render a SafeAnchor", () => {
+    wrapper.setProps({ link_text: "foo", link_url: "https://foo.com" });
+
+    assert.equal(wrapper.find(".title").children().at(0).type(), SafeAnchor);
+  });
+
+  it("should render a FluentOrText", () => {
+    wrapper.setProps({
+      link_text: "link_text",
+      title: "title",
+      link_url: "https://link_url.com",
+    });
+
+    assert.equal(
+      wrapper.find(".title-text").children().at(0).type(),
+      FluentOrText
+    );
+
+    assert.equal(wrapper.find(".link a").children().at(0).type(), FluentOrText);
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSPrivacyModal.test.jsx b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSPrivacyModal.test.jsx
new file mode 100644
index 0000000000..b4b743c7ff
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSPrivacyModal.test.jsx
@@ -0,0 +1,50 @@
+import { DSPrivacyModal } from "content-src/components/DiscoveryStreamComponents/DSPrivacyModal/DSPrivacyModal";
+import { shallow, mount } from "enzyme";
+import { actionCreators as ac } from "common/Actions.sys.mjs";
+import React from "react";
+
+describe("Discovery Stream <DSPrivacyModal>", () => {
+  let sandbox;
+  let dispatch;
+  let wrapper;
+  beforeEach(() => {
+    sandbox = sinon.createSandbox();
+    dispatch = sandbox.stub();
+    wrapper = shallow(<DSPrivacyModal dispatch={dispatch} />);
+  });
+
+  afterEach(() => {
+    sandbox.restore();
+  });
+
+  it("should contain a privacy notice", () => {
+    const modal = mount(<DSPrivacyModal />);
+    const child = modal.find(".privacy-notice");
+
+    assert.lengthOf(child, 1);
+  });
+
+  it("should call dispatch when modal is closed", () => {
+    wrapper.instance().closeModal();
+    assert.calledOnce(dispatch);
+  });
+
+  it("should call dispatch with the correct events for onLearnLinkClick", () => {
+    wrapper.instance().onLearnLinkClick();
+
+    assert.calledOnce(dispatch);
+    assert.calledWith(
+      dispatch,
+      ac.DiscoveryStreamUserEvent({
+        event: "CLICK_PRIVACY_INFO",
+        source: "DS_PRIVACY_MODAL",
+      })
+    );
+  });
+
+  it("should call dispatch with the correct events for onManageLinkClick", () => {
+    wrapper.instance().onManageLinkClick();
+
+    assert.calledOnce(dispatch);
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSSignup.test.jsx b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSSignup.test.jsx
new file mode 100644
index 0000000000..904f98e439
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSSignup.test.jsx
@@ -0,0 +1,92 @@
+import { DSSignup } from "content-src/components/DiscoveryStreamComponents/DSSignup/DSSignup";
+import React from "react";
+import { shallow } from "enzyme";
+
+describe("<DSSignup>", () => {
+  let wrapper;
+  let sandbox;
+  let dispatchStub;
+
+  beforeEach(() => {
+    sandbox = sinon.createSandbox();
+    dispatchStub = sandbox.stub();
+    wrapper = shallow(
+      <DSSignup
+        data={{
+          spocs: [
+            {
+              shim: { impression: "1234" },
+              id: "1234",
+            },
+          ],
+        }}
+        type="SIGNUP"
+        dispatch={dispatchStub}
+      />
+    );
+  });
+
+  afterEach(() => {
+    sandbox.restore();
+  });
+
+  it("should render", () => {
+    assert.ok(wrapper.exists());
+    assert.ok(wrapper.find(".ds-signup").exists());
+  });
+
+  it("should dispatch a click event on click", () => {
+    wrapper.instance().onLinkClick();
+
+    assert.calledTwice(dispatchStub);
+    assert.deepEqual(dispatchStub.firstCall.args[0].data, {
+      event: "CLICK",
+      source: "SIGNUP",
+      action_position: 0,
+    });
+    assert.deepEqual(dispatchStub.secondCall.args[0].data, {
+      source: "SIGNUP",
+      click: 0,
+      tiles: [{ id: "1234", pos: 0 }],
+    });
+  });
+
+  it("Should remove active on Menu Update", () => {
+    wrapper.setState = sandbox.stub();
+    wrapper.instance().onMenuButtonUpdate(false);
+    assert.calledWith(wrapper.setState, { active: false, lastItem: false });
+  });
+
+  it("Should add active on Menu Show", async () => {
+    wrapper.setState = sandbox.stub();
+    wrapper.instance().nextAnimationFrame = () => {};
+    await wrapper.instance().onMenuShow();
+    assert.calledWith(wrapper.setState, { active: true, lastItem: false });
+  });
+
+  it("Should add last-item to support resized window", async () => {
+    const fakeWindow = { scrollMaxX: "20" };
+    wrapper = shallow(<DSSignup windowObj={fakeWindow} />);
+    wrapper.setState = sandbox.stub();
+    wrapper.instance().nextAnimationFrame = () => {};
+    await wrapper.instance().onMenuShow();
+    assert.calledWith(wrapper.setState, { active: true, lastItem: true });
+  });
+
+  it("Should add last-item and active classes", () => {
+    wrapper.setState({
+      active: true,
+      lastItem: true,
+    });
+    assert.ok(wrapper.find(".last-item").exists());
+    assert.ok(wrapper.find(".active").exists());
+  });
+
+  it("Should call rAF from nextAnimationFrame", () => {
+    const fakeWindow = { requestAnimationFrame: sinon.stub() };
+    wrapper = shallow(<DSSignup windowObj={fakeWindow} />);
+
+    wrapper.instance().nextAnimationFrame();
+    assert.calledOnce(fakeWindow.requestAnimationFrame);
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSTextPromo.test.jsx b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSTextPromo.test.jsx
new file mode 100644
index 0000000000..0748ff701a
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/DSTextPromo.test.jsx
@@ -0,0 +1,96 @@
+import { DSTextPromo } from "content-src/components/DiscoveryStreamComponents/DSTextPromo/DSTextPromo";
+import React from "react";
+import { shallow } from "enzyme";
+
+describe("<DSTextPromo>", () => {
+  let wrapper;
+  let sandbox;
+  let dispatchStub;
+
+  beforeEach(() => {
+    sandbox = sinon.createSandbox();
+    dispatchStub = sandbox.stub();
+    wrapper = shallow(
+      <DSTextPromo
+        data={{
+          spocs: [
+            {
+              shim: { impression: "1234" },
+              id: "1234",
+            },
+          ],
+        }}
+        type="TEXTPROMO"
+        dispatch={dispatchStub}
+      />
+    );
+  });
+
+  afterEach(() => {
+    sandbox.restore();
+  });
+
+  it("should render", () => {
+    assert.ok(wrapper.exists());
+    assert.ok(wrapper.find(".ds-text-promo").exists());
+  });
+
+  it("should render a header", () => {
+    wrapper.setProps({ header: "foo" });
+    assert.ok(wrapper.find(".text").exists());
+  });
+
+  it("should render a subtitle", () => {
+    wrapper.setProps({ subtitle: "foo" });
+    assert.ok(wrapper.find(".subtitle").exists());
+  });
+
+  it("should dispatch a click event on click", () => {
+    wrapper.instance().onLinkClick();
+
+    assert.calledTwice(dispatchStub);
+    assert.deepEqual(dispatchStub.firstCall.args[0].data, {
+      event: "CLICK",
+      source: "TEXTPROMO",
+      action_position: 0,
+    });
+    assert.deepEqual(dispatchStub.secondCall.args[0].data, {
+      source: "TEXTPROMO",
+      click: 0,
+      tiles: [{ id: "1234", pos: 0 }],
+    });
+  });
+
+  it("should dispath telemety events on dismiss", () => {
+    wrapper.instance().onDismissClick();
+
+    const firstCall = dispatchStub.getCall(0);
+    const secondCall = dispatchStub.getCall(1);
+    const thirdCall = dispatchStub.getCall(2);
+
+    assert.equal(firstCall.args[0].type, "BLOCK_URL");
+    assert.deepEqual(firstCall.args[0].data, [
+      {
+        url: undefined,
+        pocket_id: undefined,
+        isSponsoredTopSite: undefined,
+        position: 0,
+        is_pocket_card: false,
+      },
+    ]);
+
+    assert.equal(secondCall.args[0].type, "DISCOVERY_STREAM_USER_EVENT");
+    assert.deepEqual(secondCall.args[0].data, {
+      event: "BLOCK",
+      source: "TEXTPROMO",
+      action_position: 0,
+    });
+
+    assert.equal(thirdCall.args[0].type, "TELEMETRY_IMPRESSION_STATS");
+    assert.deepEqual(thirdCall.args[0].data, {
+      source: "TEXTPROMO",
+      block: 0,
+      tiles: [{ id: "1234", pos: 0 }],
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/Highlights.test.jsx b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/Highlights.test.jsx
new file mode 100644
index 0000000000..d8c16d8e71
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/Highlights.test.jsx
@@ -0,0 +1,41 @@
+import { combineReducers, createStore } from "redux";
+import { INITIAL_STATE, reducers } from "common/Reducers.sys.mjs";
+import { Highlights } from "content-src/components/DiscoveryStreamComponents/Highlights/Highlights";
+import { mount } from "enzyme";
+import { Provider } from "react-redux";
+import React from "react";
+
+describe("Discovery Stream <Highlights>", () => {
+  let wrapper;
+
+  afterEach(() => {
+    wrapper.unmount();
+  });
+
+  it("should render nothing with no highlights data", () => {
+    const store = createStore(combineReducers(reducers), { ...INITIAL_STATE });
+
+    wrapper = mount(
+      <Provider store={store}>
+        <Highlights />
+      </Provider>
+    );
+
+    assert.ok(wrapper.isEmptyRender());
+  });
+
+  it("should render highlights", () => {
+    const store = createStore(combineReducers(reducers), {
+      ...INITIAL_STATE,
+      Sections: [{ id: "highlights", enabled: true }],
+    });
+
+    wrapper = mount(
+      <Provider store={store}>
+        <Highlights />
+      </Provider>
+    );
+
+    assert.lengthOf(wrapper.find(".ds-highlights"), 1);
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/HorizontalRule.test.jsx b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/HorizontalRule.test.jsx
new file mode 100644
index 0000000000..03538df6f2
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/HorizontalRule.test.jsx
@@ -0,0 +1,16 @@
+import { HorizontalRule } from "content-src/components/DiscoveryStreamComponents/HorizontalRule/HorizontalRule";
+import React from "react";
+import { shallow } from "enzyme";
+
+describe("<HorizontalRule>", () => {
+  let wrapper;
+
+  beforeEach(() => {
+    wrapper = shallow(<HorizontalRule />);
+  });
+
+  it("should render", () => {
+    assert.ok(wrapper.exists());
+    assert.ok(wrapper.find(".ds-hr").exists());
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/ImpressionStats.test.jsx b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/ImpressionStats.test.jsx
new file mode 100644
index 0000000000..4926cc6c70
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/ImpressionStats.test.jsx
@@ -0,0 +1,276 @@
+import {
+  ImpressionStats,
+  INTERSECTION_RATIO,
+} from "content-src/components/DiscoveryStreamImpressionStats/ImpressionStats";
+import { actionTypes as at } from "common/Actions.sys.mjs";
+import React from "react";
+import { shallow } from "enzyme";
+
+describe("<ImpressionStats>", () => {
+  const SOURCE = "TEST_SOURCE";
+  const FullIntersectEntries = [
+    { isIntersecting: true, intersectionRatio: INTERSECTION_RATIO },
+  ];
+  const ZeroIntersectEntries = [
+    { isIntersecting: false, intersectionRatio: 0 },
+  ];
+  const PartialIntersectEntries = [
+    { isIntersecting: true, intersectionRatio: INTERSECTION_RATIO / 2 },
+  ];
+
+  // Build IntersectionObserver class with the arg `entries` for the intersect callback.
+  function buildIntersectionObserver(entries) {
+    return class {
+      constructor(callback) {
+        this.callback = callback;
+      }
+
+      observe() {
+        this.callback(entries);
+      }
+
+      unobserve() {}
+    };
+  }
+
+  const DEFAULT_PROPS = {
+    rows: [
+      { id: 1, pos: 0 },
+      { id: 2, pos: 1 },
+      { id: 3, pos: 2 },
+    ],
+    source: SOURCE,
+    IntersectionObserver: buildIntersectionObserver(FullIntersectEntries),
+    document: {
+      visibilityState: "visible",
+      addEventListener: sinon.stub(),
+      removeEventListener: sinon.stub(),
+    },
+  };
+
+  const InnerEl = () => <div>Inner Element</div>;
+
+  function renderImpressionStats(props = {}) {
+    return shallow(
+      <ImpressionStats {...DEFAULT_PROPS} {...props}>
+        <InnerEl />
+      </ImpressionStats>
+    );
+  }
+
+  it("should render props.children", () => {
+    const wrapper = renderImpressionStats();
+    assert.ok(wrapper.contains(<InnerEl />));
+  });
+  it("should not send loaded content nor impression when the page is not visible", () => {
+    const dispatch = sinon.spy();
+    const props = {
+      dispatch,
+      document: {
+        visibilityState: "hidden",
+        addEventListener: sinon.spy(),
+        removeEventListener: sinon.spy(),
+      },
+    };
+    renderImpressionStats(props);
+
+    assert.notCalled(dispatch);
+  });
+  it("should noly send loaded content but not impression when the wrapped item is not visbible", () => {
+    const dispatch = sinon.spy();
+    const props = {
+      dispatch,
+      IntersectionObserver: buildIntersectionObserver(ZeroIntersectEntries),
+    };
+    renderImpressionStats(props);
+
+    // This one is for loaded content.
+    assert.calledOnce(dispatch);
+    const [action] = dispatch.firstCall.args;
+    assert.equal(action.type, at.DISCOVERY_STREAM_LOADED_CONTENT);
+    assert.equal(action.data.source, SOURCE);
+    assert.deepEqual(action.data.tiles, [
+      { id: 1, pos: 0 },
+      { id: 2, pos: 1 },
+      { id: 3, pos: 2 },
+    ]);
+  });
+  it("should not send impression when the wrapped item is visbible but below the ratio", () => {
+    const dispatch = sinon.spy();
+    const props = {
+      dispatch,
+      IntersectionObserver: buildIntersectionObserver(PartialIntersectEntries),
+    };
+    renderImpressionStats(props);
+
+    // This one is for loaded content.
+    assert.calledOnce(dispatch);
+  });
+  it("should send a loaded content and an impression when the page is visible and the wrapped item meets the visibility ratio", () => {
+    const dispatch = sinon.spy();
+    const props = {
+      dispatch,
+      IntersectionObserver: buildIntersectionObserver(FullIntersectEntries),
+    };
+    renderImpressionStats(props);
+
+    assert.calledTwice(dispatch);
+
+    let [action] = dispatch.firstCall.args;
+    assert.equal(action.type, at.DISCOVERY_STREAM_LOADED_CONTENT);
+    assert.equal(action.data.source, SOURCE);
+    assert.deepEqual(action.data.tiles, [
+      { id: 1, pos: 0 },
+      { id: 2, pos: 1 },
+      { id: 3, pos: 2 },
+    ]);
+
+    [action] = dispatch.secondCall.args;
+    assert.equal(action.type, at.DISCOVERY_STREAM_IMPRESSION_STATS);
+    assert.equal(action.data.source, SOURCE);
+    assert.deepEqual(action.data.tiles, [
+      { id: 1, pos: 0, type: "organic", recommendation_id: undefined },
+      { id: 2, pos: 1, type: "organic", recommendation_id: undefined },
+      { id: 3, pos: 2, type: "organic", recommendation_id: undefined },
+    ]);
+  });
+  it("should send a DISCOVERY_STREAM_SPOC_IMPRESSION when the wrapped item has a flightId", () => {
+    const dispatch = sinon.spy();
+    const flightId = "a_flight_id";
+    const props = {
+      dispatch,
+      flightId,
+      rows: [{ id: 1, pos: 1, advertiser: "test advertiser" }],
+      source: "TOP_SITES",
+      IntersectionObserver: buildIntersectionObserver(FullIntersectEntries),
+    };
+    renderImpressionStats(props);
+
+    // Loaded content + DISCOVERY_STREAM_SPOC_IMPRESSION + TOP_SITES_SPONSORED_IMPRESSION_STATS + impression
+    assert.callCount(dispatch, 4);
+
+    const [action] = dispatch.secondCall.args;
+    assert.equal(action.type, at.DISCOVERY_STREAM_SPOC_IMPRESSION);
+    assert.deepEqual(action.data, { flightId });
+  });
+  it("should send a TOP_SITES_SPONSORED_IMPRESSION_STATS when the wrapped item has a flightId", () => {
+    const dispatch = sinon.spy();
+    const flightId = "a_flight_id";
+    const props = {
+      dispatch,
+      flightId,
+      rows: [{ id: 1, pos: 1, advertiser: "test advertiser" }],
+      source: "TOP_SITES",
+      IntersectionObserver: buildIntersectionObserver(FullIntersectEntries),
+    };
+    renderImpressionStats(props);
+
+    // Loaded content + DISCOVERY_STREAM_SPOC_IMPRESSION + TOP_SITES_SPONSORED_IMPRESSION_STATS + impression
+    assert.callCount(dispatch, 4);
+
+    const [action] = dispatch.getCall(2).args;
+    assert.equal(action.type, at.TOP_SITES_SPONSORED_IMPRESSION_STATS);
+    assert.deepEqual(action.data, {
+      type: "impression",
+      tile_id: 1,
+      source: "newtab",
+      advertiser: "test advertiser",
+      position: 1,
+    });
+  });
+  it("should send an impression when the wrapped item transiting from invisible to visible", () => {
+    const dispatch = sinon.spy();
+    const props = {
+      dispatch,
+      IntersectionObserver: buildIntersectionObserver(ZeroIntersectEntries),
+    };
+    const wrapper = renderImpressionStats(props);
+
+    // For the loaded content
+    assert.calledOnce(dispatch);
+
+    let [action] = dispatch.firstCall.args;
+    assert.equal(action.type, at.DISCOVERY_STREAM_LOADED_CONTENT);
+    assert.equal(action.data.source, SOURCE);
+    assert.deepEqual(action.data.tiles, [
+      { id: 1, pos: 0 },
+      { id: 2, pos: 1 },
+      { id: 3, pos: 2 },
+    ]);
+
+    dispatch.resetHistory();
+    wrapper.instance().impressionObserver.callback(FullIntersectEntries);
+
+    // For the impression
+    assert.calledOnce(dispatch);
+
+    [action] = dispatch.firstCall.args;
+    assert.equal(action.type, at.DISCOVERY_STREAM_IMPRESSION_STATS);
+    assert.deepEqual(action.data.tiles, [
+      { id: 1, pos: 0, type: "organic", recommendation_id: undefined },
+      { id: 2, pos: 1, type: "organic", recommendation_id: undefined },
+      { id: 3, pos: 2, type: "organic", recommendation_id: undefined },
+    ]);
+  });
+  it("should remove visibility change listener when the wrapper is removed", () => {
+    const props = {
+      dispatch: sinon.spy(),
+      document: {
+        visibilityState: "hidden",
+        addEventListener: sinon.spy(),
+        removeEventListener: sinon.spy(),
+      },
+      IntersectionObserver,
+    };
+
+    const wrapper = renderImpressionStats(props);
+    assert.calledWith(props.document.addEventListener, "visibilitychange");
+    const [, listener] = props.document.addEventListener.firstCall.args;
+
+    wrapper.unmount();
+    assert.calledWith(
+      props.document.removeEventListener,
+      "visibilitychange",
+      listener
+    );
+  });
+  it("should unobserve the intersection observer when the wrapper is removed", () => {
+    const IntersectionObserver =
+      buildIntersectionObserver(ZeroIntersectEntries);
+    const spy = sinon.spy(IntersectionObserver.prototype, "unobserve");
+    const props = { dispatch: sinon.spy(), IntersectionObserver };
+
+    const wrapper = renderImpressionStats(props);
+    wrapper.unmount();
+
+    assert.calledOnce(spy);
+  });
+  it("should only send the latest impression on a visibility change", () => {
+    const listeners = new Set();
+    const props = {
+      dispatch: sinon.spy(),
+      document: {
+        visibilityState: "hidden",
+        addEventListener: (ev, cb) => listeners.add(cb),
+        removeEventListener: (ev, cb) => listeners.delete(cb),
+      },
+    };
+
+    const wrapper = renderImpressionStats(props);
+
+    // Update twice
+    wrapper.setProps({ ...props, ...{ rows: [{ id: 123, pos: 4 }] } });
+    wrapper.setProps({ ...props, ...{ rows: [{ id: 2432, pos: 5 }] } });
+
+    assert.notCalled(props.dispatch);
+
+    // Simulate listeners getting called
+    props.document.visibilityState = "visible";
+    listeners.forEach(l => l());
+
+    // Make sure we only sent the latest event
+    assert.calledTwice(props.dispatch);
+    const [action] = props.dispatch.firstCall.args;
+    assert.deepEqual(action.data.tiles, [{ id: 2432, pos: 5 }]);
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/Navigation.test.jsx b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/Navigation.test.jsx
new file mode 100644
index 0000000000..ef5baf50c1
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/Navigation.test.jsx
@@ -0,0 +1,131 @@
+import {
+  Navigation,
+  Topic,
+} from "content-src/components/DiscoveryStreamComponents/Navigation/Navigation";
+import React from "react";
+import { SafeAnchor } from "content-src/components/DiscoveryStreamComponents/SafeAnchor/SafeAnchor";
+import { FluentOrText } from "content-src/components/FluentOrText/FluentOrText";
+import { shallow, mount } from "enzyme";
+
+const DEFAULT_PROPS = {
+  App: {
+    isForStartupCache: false,
+  },
+};
+
+describe("<Navigation>", () => {
+  let wrapper;
+
+  beforeEach(() => {
+    wrapper = mount(<Navigation header={{}} locale="en-US" />);
+  });
+
+  it("should render", () => {
+    assert.ok(wrapper.exists());
+  });
+
+  it("should render a title", () => {
+    wrapper.setProps({ header: { title: "Foo" } });
+
+    assert.equal(wrapper.find(".ds-navigation-header").text(), "Foo");
+  });
+
+  it("should not render a title", () => {
+    wrapper.setProps({ header: null });
+
+    assert.lengthOf(wrapper.find(".ds-navigation-header"), 0);
+  });
+
+  it("should set default alignment", () => {
+    assert.lengthOf(wrapper.find(".ds-navigation-centered"), 1);
+  });
+
+  it("should set custom alignment", () => {
+    wrapper.setProps({ alignment: "left-align" });
+
+    assert.lengthOf(wrapper.find(".ds-navigation-left-align"), 1);
+  });
+
+  it("should set default of no links", () => {
+    assert.lengthOf(wrapper.find("ul").children(), 0);
+  });
+
+  it("should render a FluentOrText", () => {
+    wrapper.setProps({ header: { title: "Foo" } });
+
+    assert.equal(
+      wrapper.find(".ds-navigation").children().at(0).type(),
+      FluentOrText
+    );
+  });
+
+  it("should render 2 Topics", () => {
+    wrapper.setProps({
+      links: [
+        { url: "https://foo.com", name: "foo" },
+        { url: "https://bar.com", name: "bar" },
+      ],
+    });
+
+    assert.lengthOf(wrapper.find("ul").children(), 2);
+  });
+
+  it("should render 2 extra Topics", () => {
+    wrapper.setProps({
+      newFooterSection: true,
+      links: [
+        { url: "https://foo.com", name: "foo" },
+        { url: "https://bar.com", name: "bar" },
+      ],
+      extraLinks: [
+        { url: "https://foo.com", name: "foo" },
+        { url: "https://bar.com", name: "bar" },
+      ],
+    });
+
+    assert.lengthOf(wrapper.find("ul").children(), 4);
+  });
+});
+
+describe("<Topic>", () => {
+  let wrapper;
+  let sandbox;
+
+  beforeEach(() => {
+    wrapper = shallow(<Topic url="https://foo.com" name="foo" />);
+    sandbox = sinon.createSandbox();
+  });
+
+  afterEach(() => {
+    sandbox.restore();
+  });
+
+  it("should pass onLinkClick prop", () => {
+    assert.propertyVal(
+      wrapper.at(0).props(),
+      "onLinkClick",
+      wrapper.instance().onLinkClick
+    );
+  });
+
+  it("should render", () => {
+    assert.ok(wrapper.exists());
+    assert.equal(wrapper.type(), SafeAnchor);
+  });
+
+  describe("onLinkClick", () => {
+    let dispatch;
+
+    beforeEach(() => {
+      dispatch = sandbox.stub();
+      wrapper = shallow(<Topic dispatch={dispatch} {...DEFAULT_PROPS} />);
+      wrapper.setState({ isSeen: true });
+    });
+
+    it("should call dispatch", () => {
+      wrapper.instance().onLinkClick({ target: { text: `Must Reads` } });
+
+      assert.calledOnce(dispatch);
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/PrivacyLink.test.jsx b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/PrivacyLink.test.jsx
new file mode 100644
index 0000000000..285cc16c0e
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/PrivacyLink.test.jsx
@@ -0,0 +1,29 @@
+import { PrivacyLink } from "content-src/components/DiscoveryStreamComponents/PrivacyLink/PrivacyLink";
+import React from "react";
+import { shallow } from "enzyme";
+
+describe("<PrivacyLink>", () => {
+  let wrapper;
+  let sandbox;
+
+  beforeEach(() => {
+    sandbox = sinon.createSandbox();
+    wrapper = shallow(
+      <PrivacyLink
+        properties={{
+          url: "url",
+          title: "Privacy Link",
+        }}
+      />
+    );
+  });
+
+  afterEach(() => {
+    sandbox.restore();
+  });
+
+  it("should render", () => {
+    assert.ok(wrapper.exists());
+    assert.ok(wrapper.find(".ds-privacy-link").exists());
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/SafeAnchor.test.jsx b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/SafeAnchor.test.jsx
new file mode 100644
index 0000000000..5d643869b8
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/SafeAnchor.test.jsx
@@ -0,0 +1,56 @@
+import React from "react";
+import { SafeAnchor } from "content-src/components/DiscoveryStreamComponents/SafeAnchor/SafeAnchor";
+import { shallow } from "enzyme";
+
+describe("Discovery Stream <SafeAnchor>", () => {
+  let warnStub;
+  let sandbox;
+  beforeEach(() => {
+    warnStub = sinon.stub(console, "warn");
+    sandbox = sinon.createSandbox();
+  });
+  afterEach(() => {
+    warnStub.restore();
+    sandbox.restore();
+  });
+  it("should render with anchor", () => {
+    const wrapper = shallow(<SafeAnchor />);
+    assert.lengthOf(wrapper.find("a"), 1);
+  });
+  it("should render with anchor target for http", () => {
+    const wrapper = shallow(<SafeAnchor url="http://example.com" />);
+    assert.equal(wrapper.find("a").prop("href"), "http://example.com");
+  });
+  it("should render with anchor target for https", () => {
+    const wrapper = shallow(<SafeAnchor url="https://example.com" />);
+    assert.equal(wrapper.find("a").prop("href"), "https://example.com");
+  });
+  it("should not allow javascript: URIs", () => {
+    const wrapper = shallow(<SafeAnchor url="javascript:foo()" />); // eslint-disable-line no-script-url
+    assert.equal(wrapper.find("a").prop("href"), "");
+    assert.calledOnce(warnStub);
+  });
+  it("should not warn if the URL is falsey ", () => {
+    const wrapper = shallow(<SafeAnchor url="" />);
+    assert.equal(wrapper.find("a").prop("href"), "");
+    assert.notCalled(warnStub);
+  });
+  it("should dispatch an event on click", () => {
+    const dispatchStub = sandbox.stub();
+    const fakeEvent = { preventDefault: sandbox.stub(), currentTarget: {} };
+    const wrapper = shallow(<SafeAnchor dispatch={dispatchStub} />);
+
+    wrapper.find("a").simulate("click", fakeEvent);
+
+    assert.calledOnce(dispatchStub);
+    assert.calledOnce(fakeEvent.preventDefault);
+  });
+  it("should call onLinkClick if provided", () => {
+    const onLinkClickStub = sandbox.stub();
+    const wrapper = shallow(<SafeAnchor onLinkClick={onLinkClickStub} />);
+
+    wrapper.find("a").simulate("click");
+
+    assert.calledOnce(onLinkClickStub);
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/SectionTitle.test.jsx b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/SectionTitle.test.jsx
new file mode 100644
index 0000000000..b5ea007022
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/SectionTitle.test.jsx
@@ -0,0 +1,22 @@
+import React from "react";
+import { SectionTitle } from "content-src/components/DiscoveryStreamComponents/SectionTitle/SectionTitle";
+import { shallow } from "enzyme";
+
+describe("<SectionTitle>", () => {
+  let wrapper;
+
+  beforeEach(() => {
+    wrapper = shallow(<SectionTitle header={{}} />);
+  });
+
+  it("should render", () => {
+    assert.ok(wrapper.exists());
+    assert.ok(wrapper.find(".ds-section-title").exists());
+  });
+
+  it("should render a subtitle", () => {
+    wrapper.setProps({ header: { title: "Foo", subtitle: "Bar" } });
+
+    assert.equal(wrapper.find(".subtitle").text(), "Bar");
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/TopicsWidget.test.jsx b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/TopicsWidget.test.jsx
new file mode 100644
index 0000000000..f879600a8f
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/DiscoveryStreamComponents/TopicsWidget.test.jsx
@@ -0,0 +1,238 @@
+import { combineReducers, createStore } from "redux";
+import { INITIAL_STATE, reducers } from "common/Reducers.sys.mjs";
+import { Provider } from "react-redux";
+import {
+  _TopicsWidget as TopicsWidgetBase,
+  TopicsWidget,
+} from "content-src/components/DiscoveryStreamComponents/TopicsWidget/TopicsWidget";
+import { SafeAnchor } from "content-src/components/DiscoveryStreamComponents/SafeAnchor/SafeAnchor";
+import {
+  actionCreators as ac,
+  actionTypes as at,
+} from "common/Actions.sys.mjs";
+import { mount } from "enzyme";
+import React from "react";
+
+describe("Discovery Stream <TopicsWidget>", () => {
+  let sandbox;
+  let wrapper;
+  let dispatch;
+  let fakeWindow;
+
+  beforeEach(() => {
+    sandbox = sinon.createSandbox();
+    dispatch = sandbox.stub();
+    fakeWindow = {
+      innerWidth: 1000,
+      innerHeight: 900,
+    };
+
+    wrapper = mount(
+      <TopicsWidgetBase
+        dispatch={dispatch}
+        source="CARDGRID_WIDGET"
+        position={2}
+        id={1}
+        windowObj={fakeWindow}
+        DiscoveryStream={{
+          experimentData: {
+            utmCampaign: "utmCampaign",
+            utmContent: "utmContent",
+            utmSource: "utmSource",
+          },
+        }}
+      />
+    );
+  });
+
+  afterEach(() => {
+    sandbox.restore();
+  });
+
+  it("should render", () => {
+    assert.ok(wrapper.exists());
+    assert.ok(wrapper.find(".ds-topics-widget").exists());
+  });
+
+  it("should connect with DiscoveryStream store", () => {
+    let store = createStore(combineReducers(reducers), INITIAL_STATE);
+    wrapper = mount(
+      <Provider store={store}>
+        <TopicsWidget />
+      </Provider>
+    );
+
+    const topicsWidget = wrapper.find(TopicsWidgetBase);
+    assert.ok(topicsWidget.exists());
+    assert.lengthOf(topicsWidget, 1);
+    assert.deepEqual(
+      topicsWidget.props().DiscoveryStream.experimentData,
+      INITIAL_STATE.DiscoveryStream.experimentData
+    );
+  });
+
+  describe("dispatch", () => {
+    it("should dispatch loaded event", () => {
+      assert.callCount(dispatch, 1);
+      const [first] = dispatch.getCalls();
+      assert.calledWith(
+        first,
+        ac.DiscoveryStreamLoadedContent({
+          source: "CARDGRID_WIDGET",
+          tiles: [
+            {
+              id: 1,
+              pos: 2,
+            },
+          ],
+        })
+      );
+    });
+
+    it("should dispatch click event for technology", () => {
+      // Click technology topic.
+      wrapper.find(SafeAnchor).at(0).simulate("click");
+
+      // First call is DiscoveryStreamLoadedContent, which is already tested.
+      const [second, third, fourth] = dispatch.getCalls().slice(1, 4);
+
+      assert.callCount(dispatch, 4);
+      assert.calledWith(
+        second,
+        ac.OnlyToMain({
+          type: at.OPEN_LINK,
+          data: {
+            event: {
+              altKey: undefined,
+              button: undefined,
+              ctrlKey: undefined,
+              metaKey: undefined,
+              shiftKey: undefined,
+            },
+            referrer: "https://getpocket.com/recommendations",
+            url: "https://getpocket.com/explore/technology?utm_source=utmSource&utm_content=utmContent&utm_campaign=utmCampaign",
+          },
+        })
+      );
+      assert.calledWith(
+        third,
+        ac.DiscoveryStreamUserEvent({
+          event: "CLICK",
+          source: "CARDGRID_WIDGET",
+          action_position: 2,
+          value: {
+            card_type: "topics_widget",
+            topic: "technology",
+            position_in_card: 0,
+          },
+        })
+      );
+      assert.calledWith(
+        fourth,
+        ac.ImpressionStats({
+          click: 0,
+          source: "CARDGRID_WIDGET",
+          tiles: [{ id: 1, pos: 2 }],
+          window_inner_width: 1000,
+          window_inner_height: 900,
+        })
+      );
+    });
+
+    it("should dispatch click event for must reads", () => {
+      // Click must reads topic.
+      wrapper.find(SafeAnchor).at(8).simulate("click");
+
+      // First call is DiscoveryStreamLoadedContent, which is already tested.
+      const [second, third, fourth] = dispatch.getCalls().slice(1, 4);
+
+      assert.callCount(dispatch, 4);
+      assert.calledWith(
+        second,
+        ac.OnlyToMain({
+          type: at.OPEN_LINK,
+          data: {
+            event: {
+              altKey: undefined,
+              button: undefined,
+              ctrlKey: undefined,
+              metaKey: undefined,
+              shiftKey: undefined,
+            },
+            referrer: "https://getpocket.com/recommendations",
+            url: "https://getpocket.com/collections?utm_source=utmSource&utm_content=utmContent&utm_campaign=utmCampaign",
+          },
+        })
+      );
+      assert.calledWith(
+        third,
+        ac.DiscoveryStreamUserEvent({
+          event: "CLICK",
+          source: "CARDGRID_WIDGET",
+          action_position: 2,
+          value: {
+            card_type: "topics_widget",
+            topic: "must-reads",
+            position_in_card: 8,
+          },
+        })
+      );
+      assert.calledWith(
+        fourth,
+        ac.ImpressionStats({
+          click: 0,
+          source: "CARDGRID_WIDGET",
+          tiles: [{ id: 1, pos: 2 }],
+          window_inner_width: 1000,
+          window_inner_height: 900,
+        })
+      );
+    });
+
+    it("should dispatch click event for more topics", () => {
+      // Click more-topics.
+      wrapper.find(SafeAnchor).at(9).simulate("click");
+
+      // First call is DiscoveryStreamLoadedContent, which is already tested.
+      const [second, third, fourth] = dispatch.getCalls().slice(1, 4);
+
+      assert.callCount(dispatch, 4);
+      assert.calledWith(
+        second,
+        ac.OnlyToMain({
+          type: at.OPEN_LINK,
+          data: {
+            event: {
+              altKey: undefined,
+              button: undefined,
+              ctrlKey: undefined,
+              metaKey: undefined,
+              shiftKey: undefined,
+            },
+            referrer: "https://getpocket.com/recommendations",
+            url: "https://getpocket.com/?utm_source=utmSource&utm_content=utmContent&utm_campaign=utmCampaign",
+          },
+        })
+      );
+      assert.calledWith(
+        third,
+        ac.DiscoveryStreamUserEvent({
+          event: "CLICK",
+          source: "CARDGRID_WIDGET",
+          action_position: 2,
+          value: { card_type: "topics_widget", topic: "more-topics" },
+        })
+      );
+      assert.calledWith(
+        fourth,
+        ac.ImpressionStats({
+          click: 0,
+          source: "CARDGRID_WIDGET",
+          tiles: [{ id: 1, pos: 2 }],
+          window_inner_width: 1000,
+          window_inner_height: 900,
+        })
+      );
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/ErrorBoundary.test.jsx b/browser/components/newtab/test/unit/content-src/components/ErrorBoundary.test.jsx
new file mode 100644
index 0000000000..99cc8b0ca7
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/ErrorBoundary.test.jsx
@@ -0,0 +1,110 @@
+import { A11yLinkButton } from "content-src/components/A11yLinkButton/A11yLinkButton";
+import {
+  ErrorBoundary,
+  ErrorBoundaryFallback,
+} from "content-src/components/ErrorBoundary/ErrorBoundary";
+import React from "react";
+import { shallow } from "enzyme";
+
+describe("<ErrorBoundary>", () => {
+  it("should render its children if componentDidCatch wasn't called", () => {
+    const wrapper = shallow(
+      <ErrorBoundary>
+        <div className="kids" />
+      </ErrorBoundary>
+    );
+
+    assert.lengthOf(wrapper.find(".kids"), 1);
+  });
+
+  it("should render ErrorBoundaryFallback if componentDidCatch called", () => {
+    const wrapper = shallow(<ErrorBoundary />);
+
+    wrapper.instance().componentDidCatch();
+    // since shallow wrappers don't automatically manage lifecycle semantics:
+    wrapper.update();
+
+    assert.lengthOf(wrapper.find(ErrorBoundaryFallback), 1);
+  });
+
+  it("should render the given FallbackComponent if componentDidCatch called", () => {
+    class TestFallback extends React.PureComponent {
+      render() {
+        return <div className="my-fallback">doh!</div>;
+      }
+    }
+
+    const wrapper = shallow(<ErrorBoundary FallbackComponent={TestFallback} />);
+    wrapper.instance().componentDidCatch();
+    // since shallow wrappers don't automatically manage lifecycle semantics:
+    wrapper.update();
+
+    assert.lengthOf(wrapper.find(TestFallback), 1);
+  });
+
+  it("should pass the given className prop to the FallbackComponent", () => {
+    class TestFallback extends React.PureComponent {
+      render() {
+        return <div className={this.props.className}>doh!</div>;
+      }
+    }
+
+    const wrapper = shallow(
+      <ErrorBoundary FallbackComponent={TestFallback} className="sheep" />
+    );
+    wrapper.instance().componentDidCatch();
+    // since shallow wrappers don't automatically manage lifecycle semantics:
+    wrapper.update();
+
+    assert.lengthOf(wrapper.find(".sheep"), 1);
+  });
+});
+
+describe("ErrorBoundaryFallback", () => {
+  it("should render a <div> with a class of as-error-fallback", () => {
+    const wrapper = shallow(<ErrorBoundaryFallback />);
+
+    assert.lengthOf(wrapper.find("div.as-error-fallback"), 1);
+  });
+
+  it("should render a <div> with the props.className and .as-error-fallback", () => {
+    const wrapper = shallow(<ErrorBoundaryFallback className="monkeys" />);
+
+    assert.lengthOf(wrapper.find("div.monkeys.as-error-fallback"), 1);
+  });
+
+  it("should call window.location.reload(true) if .reload-button clicked", () => {
+    const fakeWindow = { location: { reload: sinon.spy() } };
+    const wrapper = shallow(<ErrorBoundaryFallback windowObj={fakeWindow} />);
+
+    wrapper.find(".reload-button").simulate("click");
+
+    assert.calledOnce(fakeWindow.location.reload);
+    assert.calledWithExactly(fakeWindow.location.reload, true);
+  });
+
+  it("should render .reload-button as an <A11yLinkButton>", () => {
+    const wrapper = shallow(<ErrorBoundaryFallback />);
+
+    assert.lengthOf(wrapper.find("A11yLinkButton.reload-button"), 1);
+  });
+
+  it("should render newtab-error-fallback-refresh-link node", () => {
+    const wrapper = shallow(<ErrorBoundaryFallback />);
+
+    const msgWrapper = wrapper.find(
+      '[data-l10n-id="newtab-error-fallback-refresh-link"]'
+    );
+    assert.lengthOf(msgWrapper, 1);
+    assert.isTrue(msgWrapper.is(A11yLinkButton));
+  });
+
+  it("should render newtab-error-fallback-info node", () => {
+    const wrapper = shallow(<ErrorBoundaryFallback />);
+
+    const msgWrapper = wrapper.find(
+      '[data-l10n-id="newtab-error-fallback-info"]'
+    );
+    assert.lengthOf(msgWrapper, 1);
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/FluentOrText.test.jsx b/browser/components/newtab/test/unit/content-src/components/FluentOrText.test.jsx
new file mode 100644
index 0000000000..165f2a6dcf
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/FluentOrText.test.jsx
@@ -0,0 +1,68 @@
+import { FluentOrText } from "content-src/components/FluentOrText/FluentOrText";
+import React from "react";
+import { shallow, mount } from "enzyme";
+
+describe("<FluentOrText>", () => {
+  it("should create span with no children", () => {
+    const wrapper = shallow(<FluentOrText />);
+
+    assert.ok(wrapper.find("span").exists());
+  });
+  it("should set plain text", () => {
+    const wrapper = shallow(<FluentOrText message={"hello"} />);
+
+    assert.equal(wrapper.text(), "hello");
+  });
+  it("should use fluent id on automatic span", () => {
+    const wrapper = shallow(<FluentOrText message={{ id: "fluent" }} />);
+
+    assert.ok(wrapper.find("span[data-l10n-id='fluent']").exists());
+  });
+  it("should also allow string_id", () => {
+    const wrapper = shallow(<FluentOrText message={{ string_id: "fluent" }} />);
+
+    assert.ok(wrapper.find("span[data-l10n-id='fluent']").exists());
+  });
+  it("should use fluent id on child", () => {
+    const wrapper = shallow(
+      <FluentOrText message={{ id: "fluent" }}>
+        <p />
+      </FluentOrText>
+    );
+
+    assert.ok(wrapper.find("p[data-l10n-id='fluent']").exists());
+  });
+  it("should set args for fluent", () => {
+    const wrapper = mount(<FluentOrText message={{ args: { num: 5 } }} />);
+    const { attributes } = wrapper.getDOMNode();
+    const args = attributes.getNamedItem("data-l10n-args").value;
+    assert.equal(JSON.parse(args).num, 5);
+  });
+  it("should also allow values", () => {
+    const wrapper = mount(<FluentOrText message={{ values: { num: 5 } }} />);
+    const { attributes } = wrapper.getDOMNode();
+    const args = attributes.getNamedItem("data-l10n-args").value;
+    assert.equal(JSON.parse(args).num, 5);
+  });
+  it("should preserve original children with fluent", () => {
+    const wrapper = shallow(
+      <FluentOrText message={{ id: "fluent" }}>
+        <p>
+          <b data-l10n-name="bold" />
+        </p>
+      </FluentOrText>
+    );
+
+    assert.ok(wrapper.find("b[data-l10n-name='bold']").exists());
+  });
+  it("should only allow a single child", () => {
+    assert.throws(() =>
+      shallow(
+        <FluentOrText>
+          <p />
+          <p />
+        </FluentOrText>
+      )
+    );
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/LinkMenu.test.jsx b/browser/components/newtab/test/unit/content-src/components/LinkMenu.test.jsx
new file mode 100644
index 0000000000..be7ac219d6
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/LinkMenu.test.jsx
@@ -0,0 +1,667 @@
+import { ContextMenu } from "content-src/components/ContextMenu/ContextMenu";
+import { _LinkMenu as LinkMenu } from "content-src/components/LinkMenu/LinkMenu";
+import React from "react";
+import { shallow } from "enzyme";
+
+describe("<LinkMenu>", () => {
+  let wrapper;
+  beforeEach(() => {
+    wrapper = shallow(
+      <LinkMenu
+        site={{ url: "" }}
+        options={["CheckPinTopSite", "CheckBookmark", "OpenInNewWindow"]}
+        dispatch={() => {}}
+      />
+    );
+  });
+  it("should render a ContextMenu element", () => {
+    assert.ok(wrapper.find(ContextMenu).exists());
+  });
+  it("should pass onUpdate, and options to ContextMenu", () => {
+    assert.ok(wrapper.find(ContextMenu).exists());
+    const contextMenuProps = wrapper.find(ContextMenu).props();
+    ["onUpdate", "options"].forEach(prop =>
+      assert.property(contextMenuProps, prop)
+    );
+  });
+  it("should give ContextMenu the correct tabbable options length for a11y", () => {
+    const { options } = wrapper.find(ContextMenu).props();
+    const [firstItem] = options;
+    const lastItem = options[options.length - 1];
+
+    // first item should have {first: true}
+    assert.isTrue(firstItem.first);
+    assert.ok(!firstItem.last);
+
+    // last item should have {last: true}
+    assert.isTrue(lastItem.last);
+    assert.ok(!lastItem.first);
+
+    // middle items should have neither
+    for (let i = 1; i < options.length - 1; i++) {
+      assert.ok(!options[i].first && !options[i].last);
+    }
+  });
+  it("should show the correct options for default sites", () => {
+    wrapper = shallow(
+      <LinkMenu
+        site={{ url: "", isDefault: true }}
+        options={["CheckBookmark"]}
+        source={"TOP_SITES"}
+        isPrivateBrowsingEnabled={true}
+        dispatch={() => {}}
+      />
+    );
+    const { options } = wrapper.find(ContextMenu).props();
+    let i = 0;
+    assert.propertyVal(options[i++], "id", "newtab-menu-pin");
+    assert.propertyVal(options[i++], "id", "newtab-menu-edit-topsites");
+    assert.propertyVal(options[i++], "type", "separator");
+    assert.propertyVal(options[i++], "id", "newtab-menu-open-new-window");
+    assert.propertyVal(
+      options[i++],
+      "id",
+      "newtab-menu-open-new-private-window"
+    );
+    assert.propertyVal(options[i++], "type", "separator");
+    assert.propertyVal(options[i++], "id", "newtab-menu-dismiss");
+    assert.propertyVal(options, "length", i);
+    // Double check that delete options are not included for default top sites
+    options
+      .filter(o => o.type !== "separator")
+      .forEach(o => {
+        assert.notInclude(["newtab-menu-delete-history"], o.id);
+      });
+  });
+  it("should show Unpin option for a pinned site if CheckPinTopSite in options list", () => {
+    wrapper = shallow(
+      <LinkMenu
+        site={{ url: "", isPinned: true }}
+        source={"TOP_SITES"}
+        options={["CheckPinTopSite"]}
+        dispatch={() => {}}
+      />
+    );
+    const { options } = wrapper.find(ContextMenu).props();
+    assert.isDefined(options.find(o => o.id && o.id === "newtab-menu-unpin"));
+  });
+  it("should show Pin option for an unpinned site if CheckPinTopSite in options list", () => {
+    wrapper = shallow(
+      <LinkMenu
+        site={{ url: "", isPinned: false }}
+        source={"TOP_SITES"}
+        options={["CheckPinTopSite"]}
+        dispatch={() => {}}
+      />
+    );
+    const { options } = wrapper.find(ContextMenu).props();
+    assert.isDefined(options.find(o => o.id && o.id === "newtab-menu-pin"));
+  });
+  it("should show Unbookmark option for a bookmarked site if CheckBookmark in options list", () => {
+    wrapper = shallow(
+      <LinkMenu
+        site={{ url: "", bookmarkGuid: 1234 }}
+        source={"TOP_SITES"}
+        options={["CheckBookmark"]}
+        dispatch={() => {}}
+      />
+    );
+    const { options } = wrapper.find(ContextMenu).props();
+    assert.isDefined(
+      options.find(o => o.id && o.id === "newtab-menu-remove-bookmark")
+    );
+  });
+  it("should show Bookmark option for an unbookmarked site if CheckBookmark in options list", () => {
+    wrapper = shallow(
+      <LinkMenu
+        site={{ url: "", bookmarkGuid: 0 }}
+        source={"TOP_SITES"}
+        options={["CheckBookmark"]}
+        dispatch={() => {}}
+      />
+    );
+    const { options } = wrapper.find(ContextMenu).props();
+    assert.isDefined(
+      options.find(o => o.id && o.id === "newtab-menu-bookmark")
+    );
+  });
+  it("should show Save to Pocket option for an unsaved Pocket item if CheckSavedToPocket in options list", () => {
+    wrapper = shallow(
+      <LinkMenu
+        site={{ url: "", bookmarkGuid: 0 }}
+        source={"HIGHLIGHTS"}
+        options={["CheckSavedToPocket"]}
+        dispatch={() => {}}
+      />
+    );
+    const { options } = wrapper.find(ContextMenu).props();
+    assert.isDefined(
+      options.find(o => o.id && o.id === "newtab-menu-save-to-pocket")
+    );
+  });
+  it("should show Delete from Pocket option for a saved Pocket item if CheckSavedToPocket in options list", () => {
+    wrapper = shallow(
+      <LinkMenu
+        site={{ url: "", pocket_id: 1234 }}
+        source={"HIGHLIGHTS"}
+        options={["CheckSavedToPocket"]}
+        dispatch={() => {}}
+      />
+    );
+    const { options } = wrapper.find(ContextMenu).props();
+    assert.isDefined(
+      options.find(o => o.id && o.id === "newtab-menu-delete-pocket")
+    );
+  });
+  it("should show Archive from Pocket option for a saved Pocket item if CheckBookmarkOrArchive", () => {
+    wrapper = shallow(
+      <LinkMenu
+        site={{ url: "", pocket_id: 1234 }}
+        source={"HIGHLIGHTS"}
+        options={["CheckBookmarkOrArchive"]}
+        dispatch={() => {}}
+      />
+    );
+    const { options } = wrapper.find(ContextMenu).props();
+    assert.isDefined(
+      options.find(o => o.id && o.id === "newtab-menu-archive-pocket")
+    );
+  });
+  it("should show Bookmark option for an unbookmarked site if CheckBookmarkOrArchive in options list and no pocket_id", () => {
+    wrapper = shallow(
+      <LinkMenu
+        site={{ url: "" }}
+        source={"HIGHLIGHTS"}
+        options={["CheckBookmarkOrArchive"]}
+        dispatch={() => {}}
+      />
+    );
+    const { options } = wrapper.find(ContextMenu).props();
+    assert.isDefined(
+      options.find(o => o.id && o.id === "newtab-menu-bookmark")
+    );
+  });
+  it("should show Unbookmark option for a bookmarked site if CheckBookmarkOrArchive in options list and no pocket_id", () => {
+    wrapper = shallow(
+      <LinkMenu
+        site={{ url: "", bookmarkGuid: 1234 }}
+        source={"HIGHLIGHTS"}
+        options={["CheckBookmarkOrArchive"]}
+        dispatch={() => {}}
+      />
+    );
+    const { options } = wrapper.find(ContextMenu).props();
+    assert.isDefined(
+      options.find(o => o.id && o.id === "newtab-menu-remove-bookmark")
+    );
+  });
+  it("should show Archive from Pocket option for a saved Pocket item if CheckArchiveFromPocket", () => {
+    wrapper = shallow(
+      <LinkMenu
+        site={{ url: "", pocket_id: 1234 }}
+        source={"TOP_STORIES"}
+        options={["CheckArchiveFromPocket"]}
+        dispatch={() => {}}
+      />
+    );
+    const { options } = wrapper.find(ContextMenu).props();
+    assert.isDefined(
+      options.find(o => o.id && o.id === "newtab-menu-archive-pocket")
+    );
+  });
+  it("should show empty from no Pocket option for no saved Pocket item if CheckArchiveFromPocket", () => {
+    wrapper = shallow(
+      <LinkMenu
+        site={{ url: "" }}
+        source={"TOP_STORIES"}
+        options={["CheckArchiveFromPocket"]}
+        dispatch={() => {}}
+      />
+    );
+    const { options } = wrapper.find(ContextMenu).props();
+    assert.isUndefined(
+      options.find(o => o.id && o.id === "newtab-menu-archive-pocket")
+    );
+  });
+  it("should show Delete from Pocket option for a saved Pocket item if CheckDeleteFromPocket", () => {
+    wrapper = shallow(
+      <LinkMenu
+        site={{ url: "", pocket_id: 1234 }}
+        source={"TOP_STORIES"}
+        options={["CheckDeleteFromPocket"]}
+        dispatch={() => {}}
+      />
+    );
+    const { options } = wrapper.find(ContextMenu).props();
+    assert.isDefined(
+      options.find(o => o.id && o.id === "newtab-menu-delete-pocket")
+    );
+  });
+  it("should show empty from Pocket option for no saved Pocket item if CheckDeleteFromPocket", () => {
+    wrapper = shallow(
+      <LinkMenu
+        site={{ url: "" }}
+        source={"TOP_STORIES"}
+        options={["CheckDeleteFromPocket"]}
+        dispatch={() => {}}
+      />
+    );
+    const { options } = wrapper.find(ContextMenu).props();
+    assert.isUndefined(
+      options.find(o => o.id && o.id === "newtab-menu-archive-pocket")
+    );
+  });
+  it("should show Open File option for a downloaded item", () => {
+    wrapper = shallow(
+      <LinkMenu
+        site={{ url: "", type: "download", path: "foo" }}
+        source={"HIGHLIGHTS"}
+        options={["OpenFile"]}
+        dispatch={() => {}}
+      />
+    );
+    const { options } = wrapper.find(ContextMenu).props();
+    assert.isDefined(
+      options.find(o => o.id && o.id === "newtab-menu-open-file")
+    );
+  });
+  it("should show Show File option for a downloaded item on a default platform", () => {
+    wrapper = shallow(
+      <LinkMenu
+        site={{ url: "", type: "download", path: "foo" }}
+        source={"HIGHLIGHTS"}
+        options={["ShowFile"]}
+        platform={"default"}
+        dispatch={() => {}}
+      />
+    );
+    const { options } = wrapper.find(ContextMenu).props();
+    assert.isDefined(
+      options.find(o => o.id && o.id === "newtab-menu-show-file")
+    );
+  });
+  it("should show Copy Downlad Link option for a downloaded item when CopyDownloadLink", () => {
+    wrapper = shallow(
+      <LinkMenu
+        site={{ url: "", type: "download" }}
+        source={"HIGHLIGHTS"}
+        options={["CopyDownloadLink"]}
+        dispatch={() => {}}
+      />
+    );
+    const { options } = wrapper.find(ContextMenu).props();
+    assert.isDefined(
+      options.find(o => o.id && o.id === "newtab-menu-copy-download-link")
+    );
+  });
+  it("should show Go To Download Page option for a downloaded item when GoToDownloadPage", () => {
+    wrapper = shallow(
+      <LinkMenu
+        site={{ url: "", type: "download", referrer: "foo" }}
+        source={"HIGHLIGHTS"}
+        options={["GoToDownloadPage"]}
+        dispatch={() => {}}
+      />
+    );
+    const { options } = wrapper.find(ContextMenu).props();
+    assert.isDefined(
+      options.find(o => o.id && o.id === "newtab-menu-go-to-download-page")
+    );
+    assert.isFalse(options[0].disabled);
+  });
+  it("should show Go To Download Page option as disabled for a downloaded item when GoToDownloadPage if no referrer exists", () => {
+    wrapper = shallow(
+      <LinkMenu
+        site={{ url: "", type: "download", referrer: null }}
+        source={"HIGHLIGHTS"}
+        options={["GoToDownloadPage"]}
+        dispatch={() => {}}
+      />
+    );
+    const { options } = wrapper.find(ContextMenu).props();
+    assert.isDefined(
+      options.find(o => o.id && o.id === "newtab-menu-go-to-download-page")
+    );
+    assert.isTrue(options[0].disabled);
+  });
+  it("should show Remove Download Link option for a downloaded item when RemoveDownload", () => {
+    wrapper = shallow(
+      <LinkMenu
+        site={{ url: "", type: "download" }}
+        source={"HIGHLIGHTS"}
+        options={["RemoveDownload"]}
+        dispatch={() => {}}
+      />
+    );
+    const { options } = wrapper.find(ContextMenu).props();
+    assert.isDefined(
+      options.find(o => o.id && o.id === "newtab-menu-remove-download")
+    );
+  });
+  it("should show Edit option", () => {
+    const props = { url: "foo", label: "label" };
+    const index = 5;
+    wrapper = shallow(
+      <LinkMenu
+        site={props}
+        index={5}
+        source={"TOP_SITES"}
+        options={["EditTopSite"]}
+        dispatch={() => {}}
+      />
+    );
+    const { options } = wrapper.find(ContextMenu).props();
+    const option = options.find(
+      o => o.id && o.id === "newtab-menu-edit-topsites"
+    );
+    assert.isDefined(option);
+    assert.equal(option.action.data.index, index);
+  });
+  describe(".onClick", () => {
+    const FAKE_EVENT = {};
+    const FAKE_INDEX = 3;
+    const FAKE_SOURCE = "TOP_SITES";
+    const FAKE_SITE = {
+      bookmarkGuid: 1234,
+      hostname: "foo",
+      path: "foo",
+      pocket_id: "1234",
+      referrer: "https://foo.com/ref",
+      title: "bar",
+      type: "bookmark",
+      typedBonus: true,
+      url: "https://foo.com",
+      sponsored_tile_id: 12345,
+    };
+    const dispatch = sinon.stub();
+    const propOptions = [
+      "ShowFile",
+      "CopyDownloadLink",
+      "GoToDownloadPage",
+      "RemoveDownload",
+      "Separator",
+      "ShowPrivacyInfo",
+      "RemoveBookmark",
+      "AddBookmark",
+      "OpenInNewWindow",
+      "OpenInPrivateWindow",
+      "BlockUrl",
+      "DeleteUrl",
+      "PinTopSite",
+      "UnpinTopSite",
+      "SaveToPocket",
+      "DeleteFromPocket",
+      "ArchiveFromPocket",
+      "WebExtDismiss",
+    ];
+    const expectedActionData = {
+      "newtab-menu-remove-bookmark": FAKE_SITE.bookmarkGuid,
+      "newtab-menu-bookmark": {
+        url: FAKE_SITE.url,
+        title: FAKE_SITE.title,
+        type: FAKE_SITE.type,
+      },
+      "newtab-menu-open-new-window": {
+        url: FAKE_SITE.url,
+        referrer: FAKE_SITE.referrer,
+        typedBonus: FAKE_SITE.typedBonus,
+        sponsored_tile_id: FAKE_SITE.sponsored_tile_id,
+      },
+      "newtab-menu-open-new-private-window": {
+        url: FAKE_SITE.url,
+        referrer: FAKE_SITE.referrer,
+      },
+      "newtab-menu-dismiss": [
+        {
+          url: FAKE_SITE.url,
+          pocket_id: FAKE_SITE.pocket_id,
+          isSponsoredTopSite: undefined,
+          position: 3,
+          tile_id: 12345,
+          is_pocket_card: false,
+        },
+      ],
+      menu_action_webext_dismiss: {
+        source: "TOP_SITES",
+        url: FAKE_SITE.url,
+        action_position: 3,
+      },
+      "newtab-menu-delete-history": {
+        url: FAKE_SITE.url,
+        pocket_id: FAKE_SITE.pocket_id,
+        forceBlock: FAKE_SITE.bookmarkGuid,
+      },
+      "newtab-menu-pin": { site: FAKE_SITE, index: FAKE_INDEX },
+      "newtab-menu-unpin": { site: { url: FAKE_SITE.url } },
+      "newtab-menu-save-to-pocket": {
+        site: { url: FAKE_SITE.url, title: FAKE_SITE.title },
+      },
+      "newtab-menu-delete-pocket": { pocket_id: "1234" },
+      "newtab-menu-archive-pocket": { pocket_id: "1234" },
+      "newtab-menu-show-file": { url: FAKE_SITE.url },
+      "newtab-menu-copy-download-link": { url: FAKE_SITE.url },
+      "newtab-menu-go-to-download-page": { url: FAKE_SITE.referrer },
+      "newtab-menu-remove-download": { url: FAKE_SITE.url },
+    };
+    const { options } = shallow(
+      <LinkMenu
+        site={FAKE_SITE}
+        siteInfo={{ value: { card_type: FAKE_SITE.type } }}
+        dispatch={dispatch}
+        index={FAKE_INDEX}
+        isPrivateBrowsingEnabled={true}
+        platform={"default"}
+        options={propOptions}
+        source={FAKE_SOURCE}
+        shouldSendImpressionStats={true}
+      />
+    )
+      .find(ContextMenu)
+      .props();
+    afterEach(() => dispatch.reset());
+    options
+      .filter(o => o.type !== "separator")
+      .forEach(option => {
+        it(`should fire a ${option.action.type} action for ${option.id} with the expected data`, () => {
+          option.onClick(FAKE_EVENT);
+
+          if (option.impression && option.userEvent) {
+            assert.calledThrice(dispatch);
+          } else if (option.impression || option.userEvent) {
+            assert.calledTwice(dispatch);
+          } else {
+            assert.calledOnce(dispatch);
+          }
+
+          // option.action is dispatched
+          assert.ok(dispatch.firstCall.calledWith(option.action));
+
+          // option.action has correct data
+          // (delete is a special case as it dispatches a nested DIALOG_OPEN-type action)
+          // in the case of this FAKE_SITE, we send a bookmarkGuid therefore we also want
+          // to block this if we delete it
+          if (option.id === "newtab-menu-delete-history") {
+            assert.deepEqual(
+              option.action.data.onConfirm[0].data,
+              expectedActionData[option.id]
+            );
+            // Test UserEvent send correct meta about item deleted
+            assert.propertyVal(
+              option.action.data.onConfirm[1].data,
+              "action_position",
+              FAKE_INDEX
+            );
+            assert.propertyVal(
+              option.action.data.onConfirm[1].data,
+              "source",
+              FAKE_SOURCE
+            );
+          } else {
+            assert.deepEqual(option.action.data, expectedActionData[option.id]);
+          }
+        });
+        it(`should fire a UserEvent action for ${option.id} if configured`, () => {
+          if (option.userEvent) {
+            option.onClick(FAKE_EVENT);
+            const [action] = dispatch.secondCall.args;
+            assert.isUserEventAction(action);
+            assert.propertyVal(action.data, "source", FAKE_SOURCE);
+            assert.propertyVal(action.data, "action_position", FAKE_INDEX);
+            assert.propertyVal(action.data.value, "card_type", FAKE_SITE.type);
+          }
+        });
+        it(`should send impression stats for ${option.id}`, () => {
+          if (option.impression) {
+            option.onClick(FAKE_EVENT);
+            const [action] = dispatch.thirdCall.args;
+            assert.deepEqual(action, option.impression);
+          }
+        });
+      });
+    it(`should not send impression stats if not configured`, () => {
+      const fakeOptions = shallow(
+        <LinkMenu
+          site={FAKE_SITE}
+          dispatch={dispatch}
+          index={FAKE_INDEX}
+          options={propOptions}
+          source={FAKE_SOURCE}
+          shouldSendImpressionStats={false}
+        />
+      )
+        .find(ContextMenu)
+        .props().options;
+
+      fakeOptions
+        .filter(o => o.type !== "separator")
+        .forEach(option => {
+          if (option.impression) {
+            option.onClick(FAKE_EVENT);
+            assert.calledTwice(dispatch);
+            assert.notEqual(dispatch.firstCall.args[0], option.impression);
+            assert.notEqual(dispatch.secondCall.args[0], option.impression);
+            dispatch.reset();
+          }
+        });
+    });
+    it(`should pin a SPOC with all of the site details sent`, () => {
+      const pinSpocTopSite = "PinTopSite";
+      const { options: spocOptions } = shallow(
+        <LinkMenu
+          site={FAKE_SITE}
+          siteInfo={{ value: { card_type: FAKE_SITE.type } }}
+          dispatch={dispatch}
+          index={FAKE_INDEX}
+          isPrivateBrowsingEnabled={true}
+          platform={"default"}
+          options={[pinSpocTopSite]}
+          source={FAKE_SOURCE}
+          shouldSendImpressionStats={true}
+        />
+      )
+        .find(ContextMenu)
+        .props();
+
+      const [pinSpocOption] = spocOptions;
+      pinSpocOption.onClick(FAKE_EVENT);
+
+      if (pinSpocOption.impression && pinSpocOption.userEvent) {
+        assert.calledThrice(dispatch);
+      } else if (pinSpocOption.impression || pinSpocOption.userEvent) {
+        assert.calledTwice(dispatch);
+      } else {
+        assert.calledOnce(dispatch);
+      }
+
+      // option.action is dispatched
+      assert.ok(dispatch.firstCall.calledWith(pinSpocOption.action));
+
+      assert.deepEqual(pinSpocOption.action.data, {
+        site: FAKE_SITE,
+        index: FAKE_INDEX,
+      });
+    });
+    it(`should create a proper BLOCK_URL action for a sponsored tile`, () => {
+      const site = {
+        hostname: "foo",
+        path: "foo",
+        referrer: "https://foo.com/ref",
+        title: "bar",
+        type: "bookmark",
+        typedBonus: true,
+        url: "https://foo.com",
+        sponsored_position: 1,
+      };
+      const { options: blockOptions } = shallow(
+        <LinkMenu
+          site={site}
+          siteInfo={{ value: { card_type: site.type } }}
+          dispatch={dispatch}
+          index={FAKE_INDEX}
+          isPrivateBrowsingEnabled={true}
+          platform={"default"}
+          options={["BlockUrl"]}
+          source={FAKE_SOURCE}
+          shouldSendImpressionStats={true}
+        />
+      )
+        .find(ContextMenu)
+        .props();
+      const [blockUrlOption] = blockOptions;
+
+      blockUrlOption.onClick(FAKE_EVENT);
+
+      assert.calledThrice(dispatch);
+      assert.ok(dispatch.firstCall.calledWith(blockUrlOption.action));
+      const expected = {
+        url: site.url,
+        pocket_id: undefined,
+        advertiser_name: site.hostname,
+        isSponsoredTopSite: 1,
+        position: 3,
+        is_pocket_card: false,
+      };
+      assert.deepEqual(blockUrlOption.action.data[0], expected);
+    });
+    it(`should create a proper BLOCK_URL action for a pocket item`, () => {
+      const site = {
+        hostname: "foo",
+        path: "foo",
+        referrer: "https://foo.com/ref",
+        title: "bar",
+        type: "CardGrid",
+        typedBonus: true,
+        url: "https://foo.com",
+      };
+      const { options: blockOptions } = shallow(
+        <LinkMenu
+          site={site}
+          siteInfo={{ value: { card_type: site.type } }}
+          dispatch={dispatch}
+          index={FAKE_INDEX}
+          isPrivateBrowsingEnabled={true}
+          platform={"default"}
+          options={["BlockUrl"]}
+          source={FAKE_SOURCE}
+          shouldSendImpressionStats={true}
+        />
+      )
+        .find(ContextMenu)
+        .props();
+      const [blockUrlOption] = blockOptions;
+
+      blockUrlOption.onClick(FAKE_EVENT);
+
+      assert.calledThrice(dispatch);
+      assert.ok(dispatch.firstCall.calledWith(blockUrlOption.action));
+      const expected = {
+        url: site.url,
+        pocket_id: undefined,
+        isSponsoredTopSite: undefined,
+        position: 3,
+        is_pocket_card: true,
+      };
+      assert.deepEqual(blockUrlOption.action.data[0], expected);
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/MoreRecommendations.test.jsx b/browser/components/newtab/test/unit/content-src/components/MoreRecommendations.test.jsx
new file mode 100644
index 0000000000..2b3c06b6bf
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/MoreRecommendations.test.jsx
@@ -0,0 +1,24 @@
+import { MoreRecommendations } from "content-src/components/MoreRecommendations/MoreRecommendations";
+import React from "react";
+import { shallow } from "enzyme";
+
+describe("<MoreRecommendations>", () => {
+  it("should render a MoreRecommendations element", () => {
+    const wrapper = shallow(<MoreRecommendations />);
+    assert.ok(wrapper.exists());
+  });
+  it("should render a link when provided with read_more_endpoint prop", () => {
+    const wrapper = shallow(
+      <MoreRecommendations read_more_endpoint="https://endpoint.com" />
+    );
+
+    const link = wrapper.find(".more-recommendations");
+    assert.lengthOf(link, 1);
+  });
+  it("should not render a link when provided with read_more_endpoint prop", () => {
+    const wrapper = shallow(<MoreRecommendations read_more_endpoint="" />);
+
+    const link = wrapper.find(".more-recommendations");
+    assert.lengthOf(link, 0);
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/PocketLoggedInCta.test.jsx b/browser/components/newtab/test/unit/content-src/components/PocketLoggedInCta.test.jsx
new file mode 100644
index 0000000000..31a5e7be4d
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/PocketLoggedInCta.test.jsx
@@ -0,0 +1,46 @@
+import { combineReducers, createStore } from "redux";
+import { INITIAL_STATE, reducers } from "common/Reducers.sys.mjs";
+import { mount, shallow } from "enzyme";
+import {
+  PocketLoggedInCta,
+  _PocketLoggedInCta as PocketLoggedInCtaRaw,
+} from "content-src/components/PocketLoggedInCta/PocketLoggedInCta";
+import { Provider } from "react-redux";
+import React from "react";
+
+function mountSectionWithProps(props) {
+  const store = createStore(combineReducers(reducers), INITIAL_STATE);
+  return mount(
+    <Provider store={store}>
+      <PocketLoggedInCta {...props} />
+    </Provider>
+  );
+}
+
+describe("<PocketLoggedInCta>", () => {
+  it("should render a PocketLoggedInCta element", () => {
+    const wrapper = mountSectionWithProps({});
+    assert.ok(wrapper.exists());
+  });
+  it("should render Fluent spans when rendered without props", () => {
+    const wrapper = mountSectionWithProps({});
+
+    const message = wrapper.find("span[data-l10n-id]");
+    assert.lengthOf(message, 2);
+  });
+  it("should not render Fluent spans when rendered with props", () => {
+    const wrapper = shallow(
+      <PocketLoggedInCtaRaw
+        Pocket={{
+          pocketCta: {
+            ctaButton: "button",
+            ctaText: "text",
+          },
+        }}
+      />
+    );
+
+    const message = wrapper.find("span[data-l10n-id]");
+    assert.lengthOf(message, 0);
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/Search.test.jsx b/browser/components/newtab/test/unit/content-src/components/Search.test.jsx
new file mode 100644
index 0000000000..54a3b611cc
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/Search.test.jsx
@@ -0,0 +1,179 @@
+import { GlobalOverrider } from "test/unit/utils";
+import { mount, shallow } from "enzyme";
+import React from "react";
+import { _Search as Search } from "content-src/components/Search/Search";
+
+const DEFAULT_PROPS = {
+  dispatch() {},
+  Prefs: { values: { featureConfig: {} } },
+};
+
+describe("<Search>", () => {
+  let globals;
+  let sandbox;
+  beforeEach(() => {
+    globals = new GlobalOverrider();
+    sandbox = globals.sandbox;
+
+    global.ContentSearchUIController.prototype = { search: sandbox.spy() };
+  });
+  afterEach(() => {
+    globals.restore();
+  });
+
+  it("should render a Search element", () => {
+    const wrapper = shallow(<Search {...DEFAULT_PROPS} />);
+    assert.ok(wrapper.exists());
+  });
+  it("should not use a <form> element", () => {
+    const wrapper = mount(<Search {...DEFAULT_PROPS} />);
+
+    assert.equal(wrapper.find("form").length, 0);
+  });
+  it("should listen for ContentSearchClient on render", () => {
+    const spy = globals.set("addEventListener", sandbox.spy());
+
+    const wrapper = mount(<Search {...DEFAULT_PROPS} />);
+
+    assert.calledOnce(spy.withArgs("ContentSearchClient", wrapper.instance()));
+  });
+  it("should stop listening for ContentSearchClient on unmount", () => {
+    const spy = globals.set("removeEventListener", sandbox.spy());
+    const wrapper = mount(<Search {...DEFAULT_PROPS} />);
+    // cache the instance as we can't call this method after unmount is called
+    const instance = wrapper.instance();
+
+    wrapper.unmount();
+
+    assert.calledOnce(spy.withArgs("ContentSearchClient", instance));
+  });
+  it("should add gContentSearchController as a global", () => {
+    // current about:home tests need gContentSearchController to exist as a global
+    // so let's test it here too to ensure we don't break this behaviour
+    mount(<Search {...DEFAULT_PROPS} />);
+    assert.property(window, "gContentSearchController");
+    assert.ok(window.gContentSearchController);
+  });
+  it("should pass along search when clicking the search button", () => {
+    const wrapper = mount(<Search {...DEFAULT_PROPS} />);
+
+    wrapper.find(".search-button").simulate("click");
+
+    const { search } = window.gContentSearchController;
+    assert.calledOnce(search);
+    assert.propertyVal(search.firstCall.args[0], "type", "click");
+  });
+  it("should send a UserEvent action", () => {
+    global.ContentSearchUIController.prototype.search = () => {
+      dispatchEvent(
+        new CustomEvent("ContentSearchClient", { detail: { type: "Search" } })
+      );
+    };
+    const dispatch = sinon.spy();
+    const wrapper = mount(<Search {...DEFAULT_PROPS} dispatch={dispatch} />);
+
+    wrapper.find(".search-button").simulate("click");
+
+    assert.calledOnce(dispatch);
+    const [action] = dispatch.firstCall.args;
+    assert.isUserEventAction(action);
+    assert.propertyVal(action.data, "event", "SEARCH");
+  });
+  it("should show our logo when the prop exists.", () => {
+    const showLogoProps = Object.assign({}, DEFAULT_PROPS, { showLogo: true });
+
+    const wrapper = shallow(<Search {...showLogoProps} />);
+    assert.lengthOf(wrapper.find(".logo-and-wordmark"), 1);
+  });
+  it("should not show our logo when the prop does not exist.", () => {
+    const hideLogoProps = Object.assign({}, DEFAULT_PROPS, { showLogo: false });
+
+    const wrapper = shallow(<Search {...hideLogoProps} />);
+    assert.lengthOf(wrapper.find(".logo-and-wordmark"), 0);
+  });
+
+  describe("Search Hand-off", () => {
+    it("should render a Search element when hand-off is enabled", () => {
+      const wrapper = shallow(
+        <Search {...DEFAULT_PROPS} handoffEnabled={true} />
+      );
+      assert.ok(wrapper.exists());
+      assert.equal(wrapper.find(".search-handoff-button").length, 1);
+    });
+    it("should hand-off search when button is clicked", () => {
+      const dispatch = sinon.spy();
+      const wrapper = shallow(
+        <Search {...DEFAULT_PROPS} handoffEnabled={true} dispatch={dispatch} />
+      );
+      wrapper
+        .find(".search-handoff-button")
+        .simulate("click", { preventDefault: () => {} });
+      assert.calledThrice(dispatch);
+      assert.calledWith(dispatch, {
+        data: { text: undefined },
+        meta: {
+          from: "ActivityStream:Content",
+          skipLocal: true,
+          to: "ActivityStream:Main",
+        },
+        type: "HANDOFF_SEARCH_TO_AWESOMEBAR",
+      });
+      assert.calledWith(dispatch, { type: "FAKE_FOCUS_SEARCH" });
+      const [action] = dispatch.thirdCall.args;
+      assert.isUserEventAction(action);
+      assert.propertyVal(action.data, "event", "SEARCH_HANDOFF");
+    });
+    it("should hand-off search on paste", () => {
+      const dispatch = sinon.spy();
+      const wrapper = mount(
+        <Search {...DEFAULT_PROPS} handoffEnabled={true} dispatch={dispatch} />
+      );
+      wrapper.instance()._searchHandoffButton = { contains: () => true };
+      wrapper.instance().onSearchHandoffPaste({
+        clipboardData: {
+          getData: () => "some copied text",
+        },
+        preventDefault: () => {},
+      });
+      assert.equal(dispatch.callCount, 4);
+      assert.calledWith(dispatch, {
+        data: { text: "some copied text" },
+        meta: {
+          from: "ActivityStream:Content",
+          skipLocal: true,
+          to: "ActivityStream:Main",
+        },
+        type: "HANDOFF_SEARCH_TO_AWESOMEBAR",
+      });
+      assert.calledWith(dispatch, { type: "DISABLE_SEARCH" });
+      const [action] = dispatch.thirdCall.args;
+      assert.isUserEventAction(action);
+      assert.propertyVal(action.data, "event", "SEARCH_HANDOFF");
+    });
+    it("should properly handle drop events", () => {
+      const dispatch = sinon.spy();
+      const wrapper = mount(
+        <Search {...DEFAULT_PROPS} handoffEnabled={true} dispatch={dispatch} />
+      );
+      const preventDefault = sinon.spy();
+      wrapper.find(".fake-editable").simulate("drop", {
+        dataTransfer: { getData: () => "dropped text" },
+        preventDefault,
+      });
+      assert.equal(dispatch.callCount, 4);
+      assert.calledWith(dispatch, {
+        data: { text: "dropped text" },
+        meta: {
+          from: "ActivityStream:Content",
+          skipLocal: true,
+          to: "ActivityStream:Main",
+        },
+        type: "HANDOFF_SEARCH_TO_AWESOMEBAR",
+      });
+      assert.calledWith(dispatch, { type: "DISABLE_SEARCH" });
+      const [action] = dispatch.thirdCall.args;
+      assert.isUserEventAction(action);
+      assert.propertyVal(action.data, "event", "SEARCH_HANDOFF");
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/Sections.test.jsx b/browser/components/newtab/test/unit/content-src/components/Sections.test.jsx
new file mode 100644
index 0000000000..9f4008369a
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/Sections.test.jsx
@@ -0,0 +1,600 @@
+import { combineReducers, createStore } from "redux";
+import { INITIAL_STATE, reducers } from "common/Reducers.sys.mjs";
+import {
+  Section,
+  SectionIntl,
+  _Sections as Sections,
+} from "content-src/components/Sections/Sections";
+import { actionTypes as at } from "common/Actions.sys.mjs";
+import { mount, shallow } from "enzyme";
+import { PlaceholderCard } from "content-src/components/Card/Card";
+import { PocketLoggedInCta } from "content-src/components/PocketLoggedInCta/PocketLoggedInCta";
+import { Provider } from "react-redux";
+import React from "react";
+import { Topics } from "content-src/components/Topics/Topics";
+import { TopSites } from "content-src/components/TopSites/TopSites";
+
+function mountSectionWithProps(props) {
+  const store = createStore(combineReducers(reducers), INITIAL_STATE);
+  return mount(
+    <Provider store={store}>
+      <Section {...props} />
+    </Provider>
+  );
+}
+
+function mountSectionIntlWithProps(props) {
+  const store = createStore(combineReducers(reducers), INITIAL_STATE);
+  return mount(
+    <Provider store={store}>
+      <SectionIntl {...props} />
+    </Provider>
+  );
+}
+
+describe("<Sections>", () => {
+  let wrapper;
+  let FAKE_SECTIONS;
+  beforeEach(() => {
+    FAKE_SECTIONS = new Array(5).fill(null).map((v, i) => ({
+      id: `foo_bar_${i}`,
+      title: `Foo Bar ${i}`,
+      enabled: !!(i % 2),
+      rows: [],
+    }));
+    wrapper = shallow(
+      <Sections
+        Sections={FAKE_SECTIONS}
+        Prefs={{
+          values: { sectionOrder: FAKE_SECTIONS.map(i => i.id).join(",") },
+        }}
+      />
+    );
+  });
+  it("should render a Sections element", () => {
+    assert.ok(wrapper.exists());
+  });
+  it("should render a Section for each one passed in props.Sections with .enabled === true", () => {
+    const sectionElems = wrapper.find(SectionIntl);
+    assert.lengthOf(sectionElems, 2);
+    sectionElems.forEach((section, i) => {
+      assert.equal(section.props().id, FAKE_SECTIONS[2 * i + 1].id);
+      assert.equal(section.props().enabled, true);
+    });
+  });
+  it("should render Top Sites if feeds.topsites pref is true", () => {
+    wrapper = shallow(
+      <Sections
+        Sections={FAKE_SECTIONS}
+        Prefs={{
+          values: {
+            "feeds.topsites": true,
+            sectionOrder: "topsites,topstories,highlights",
+          },
+        }}
+      />
+    );
+    assert.equal(wrapper.find(TopSites).length, 1);
+  });
+  it("should NOT render Top Sites if feeds.topsites pref is false", () => {
+    wrapper = shallow(
+      <Sections
+        Sections={FAKE_SECTIONS}
+        Prefs={{
+          values: {
+            "feeds.topsites": false,
+            sectionOrder: "topsites,topstories,highlights",
+          },
+        }}
+      />
+    );
+    assert.equal(wrapper.find(TopSites).length, 0);
+  });
+  it("should render the sections in the order specifed by sectionOrder pref", () => {
+    wrapper = shallow(
+      <Sections
+        Sections={FAKE_SECTIONS}
+        Prefs={{ values: { sectionOrder: "foo_bar_1,foo_bar_3" } }}
+      />
+    );
+    let sections = wrapper.find(SectionIntl);
+    assert.lengthOf(sections, 2);
+    assert.equal(sections.first().props().id, "foo_bar_1");
+    assert.equal(sections.last().props().id, "foo_bar_3");
+    wrapper = shallow(
+      <Sections
+        Sections={FAKE_SECTIONS}
+        Prefs={{ values: { sectionOrder: "foo_bar_3,foo_bar_1" } }}
+      />
+    );
+    sections = wrapper.find(SectionIntl);
+    assert.lengthOf(sections, 2);
+    assert.equal(sections.first().props().id, "foo_bar_3");
+    assert.equal(sections.last().props().id, "foo_bar_1");
+  });
+});
+
+describe("<Section>", () => {
+  let wrapper;
+  let FAKE_SECTION;
+
+  beforeEach(() => {
+    FAKE_SECTION = {
+      id: `foo_bar_1`,
+      pref: { collapsed: false },
+      title: `Foo Bar 1`,
+      rows: [{ link: "http://localhost", index: 0 }],
+      emptyState: {
+        icon: "check",
+        message: "Some message",
+      },
+      rowsPref: "section.rows",
+      maxRows: 4,
+      Prefs: { values: { "section.rows": 2 } },
+    };
+    wrapper = mountSectionIntlWithProps(FAKE_SECTION);
+  });
+
+  describe("placeholders", () => {
+    const CARDS_PER_ROW = 3;
+    const fakeSite = { link: "http://localhost" };
+    function renderWithSites(rows) {
+      const store = createStore(combineReducers(reducers), INITIAL_STATE);
+      return mount(
+        <Provider store={store}>
+          <Section {...FAKE_SECTION} rows={rows} />
+        </Provider>
+      );
+    }
+
+    it("should return 2 row of placeholders if realRows is 0", () => {
+      wrapper = renderWithSites([]);
+      assert.lengthOf(wrapper.find(PlaceholderCard), 6);
+    });
+    it("should fill in the rest of the rows", () => {
+      wrapper = renderWithSites(new Array(CARDS_PER_ROW).fill(fakeSite));
+      assert.lengthOf(
+        wrapper.find(PlaceholderCard),
+        CARDS_PER_ROW,
+        "CARDS_PER_ROW"
+      );
+
+      wrapper = renderWithSites(new Array(CARDS_PER_ROW + 1).fill(fakeSite));
+      assert.lengthOf(wrapper.find(PlaceholderCard), 2, "CARDS_PER_ROW + 1");
+
+      wrapper = renderWithSites(new Array(CARDS_PER_ROW + 2).fill(fakeSite));
+      assert.lengthOf(wrapper.find(PlaceholderCard), 1, "CARDS_PER_ROW + 2");
+
+      wrapper = renderWithSites(
+        new Array(2 * CARDS_PER_ROW - 1).fill(fakeSite)
+      );
+      assert.lengthOf(wrapper.find(PlaceholderCard), 1, "CARDS_PER_ROW - 1");
+    });
+    it("should not add placeholders all the rows are full", () => {
+      wrapper = renderWithSites(new Array(2 * CARDS_PER_ROW).fill(fakeSite));
+      assert.lengthOf(wrapper.find(PlaceholderCard), 0, "2 rows");
+    });
+  });
+
+  describe("empty state", () => {
+    beforeEach(() => {
+      Object.assign(FAKE_SECTION, {
+        initialized: true,
+        dispatch: () => {},
+        rows: [],
+        emptyState: {
+          message: "Some message",
+        },
+      });
+      wrapper = shallow(<Section {...FAKE_SECTION} />);
+    });
+    it("should be shown when rows is empty and initialized is true", () => {
+      assert.ok(wrapper.find(".empty-state").exists());
+    });
+    it("should not be shown in initialized is false", () => {
+      Object.assign(FAKE_SECTION, {
+        initialized: false,
+        rows: [],
+        emptyState: {
+          message: "Some message",
+        },
+      });
+      wrapper = shallow(<Section {...FAKE_SECTION} />);
+      assert.isFalse(wrapper.find(".empty-state").exists());
+    });
+    it("no icon should be shown", () => {
+      assert.lengthOf(wrapper.find(".icon"), 0);
+    });
+  });
+
+  describe("topics component", () => {
+    let TOP_STORIES_SECTION;
+    beforeEach(() => {
+      TOP_STORIES_SECTION = {
+        id: "topstories",
+        title: "TopStories",
+        pref: { collapsed: false },
+        rows: [{ guid: 1, link: "http://localhost", isDefault: true }],
+        topics: [],
+        read_more_endpoint: "http://localhost/read-more",
+        maxRows: 1,
+        eventSource: "TOP_STORIES",
+      };
+    });
+    it("should not render for empty topics", () => {
+      wrapper = mountSectionIntlWithProps(TOP_STORIES_SECTION);
+
+      assert.lengthOf(wrapper.find(".topic"), 0);
+    });
+    it("should render for non-empty topics", () => {
+      TOP_STORIES_SECTION.topics = [{ name: "topic1", url: "topic-url1" }];
+      wrapper = shallow(
+        <Section
+          Pocket={{ pocketCta: { useCta: true }, isUserLoggedIn: true }}
+          {...TOP_STORIES_SECTION}
+        />
+      );
+
+      assert.lengthOf(wrapper.find(Topics), 1);
+      assert.lengthOf(wrapper.find(PocketLoggedInCta), 0);
+    });
+    it("should delay render of third rec to give time for potential spoc", async () => {
+      TOP_STORIES_SECTION.rows = [
+        { guid: 1, link: "http://localhost" },
+        { guid: 2, link: "http://localhost" },
+        { guid: 3, link: "http://localhost" },
+      ];
+      wrapper = shallow(
+        <Section
+          Pocket={{ waitingForSpoc: true, pocketCta: {} }}
+          {...TOP_STORIES_SECTION}
+        />
+      );
+      assert.lengthOf(wrapper.find(PlaceholderCard), 1);
+
+      wrapper.setProps({
+        Pocket: {
+          waitingForSpoc: false,
+          pocketCta: {},
+        },
+      });
+      assert.lengthOf(wrapper.find(PlaceholderCard), 0);
+    });
+    it("should render container for uninitialized topics to ensure content doesn't shift", () => {
+      delete TOP_STORIES_SECTION.topics;
+
+      wrapper = mountSectionIntlWithProps(TOP_STORIES_SECTION);
+
+      assert.lengthOf(wrapper.find(".top-stories-bottom-container"), 1);
+      assert.lengthOf(wrapper.find(Topics), 0);
+      assert.lengthOf(wrapper.find(PocketLoggedInCta), 0);
+    });
+
+    it("should render a pocket cta if not logged in and set to display cta", () => {
+      TOP_STORIES_SECTION.topics = [{ name: "topic1", url: "topic-url1" }];
+      wrapper = shallow(
+        <Section
+          Pocket={{ pocketCta: { useCta: true }, isUserLoggedIn: false }}
+          {...TOP_STORIES_SECTION}
+        />
+      );
+
+      assert.lengthOf(wrapper.find(Topics), 0);
+      assert.lengthOf(wrapper.find(PocketLoggedInCta), 1);
+    });
+    it("should render nothing while loading to avoid a flicker of log in state", () => {
+      TOP_STORIES_SECTION.topics = [{ name: "topic1", url: "topic-url1" }];
+      wrapper = shallow(
+        <Section
+          Pocket={{ pocketCta: { useCta: false } }}
+          {...TOP_STORIES_SECTION}
+        />
+      );
+
+      assert.lengthOf(wrapper.find(Topics), 0);
+      assert.lengthOf(wrapper.find(PocketLoggedInCta), 0);
+    });
+    it("should render a topics list if set to not display cta with either logged or out", () => {
+      TOP_STORIES_SECTION.topics = [{ name: "topic1", url: "topic-url1" }];
+      wrapper = shallow(
+        <Section
+          Pocket={{ pocketCta: { useCta: false }, isUserLoggedIn: false }}
+          {...TOP_STORIES_SECTION}
+        />
+      );
+
+      assert.lengthOf(wrapper.find(Topics), 1);
+      assert.lengthOf(wrapper.find(PocketLoggedInCta), 0);
+
+      wrapper = shallow(
+        <Section
+          Pocket={{ pocketCta: { useCta: false }, isUserLoggedIn: true }}
+          {...TOP_STORIES_SECTION}
+        />
+      );
+
+      assert.lengthOf(wrapper.find(Topics), 1);
+      assert.lengthOf(wrapper.find(PocketLoggedInCta), 0);
+    });
+    it("should render nothing if set to display a cta and not logged in or out (waiting for state)", () => {
+      TOP_STORIES_SECTION.topics = [{ name: "topic1", url: "topic-url1" }];
+      wrapper = shallow(
+        <Section
+          Pocket={{ pocketCta: { useCta: true } }}
+          {...TOP_STORIES_SECTION}
+        />
+      );
+
+      assert.lengthOf(wrapper.find(Topics), 0);
+      assert.lengthOf(wrapper.find(PocketLoggedInCta), 0);
+    });
+  });
+
+  describe("impression stats", () => {
+    const FAKE_TOPSTORIES_SECTION_PROPS = {
+      id: "TopStories",
+      title: "Foo Bar 1",
+      pref: { collapsed: false },
+      maxRows: 1,
+      rows: [{ guid: 1 }, { guid: 2 }],
+      shouldSendImpressionStats: true,
+
+      document: {
+        visibilityState: "visible",
+        addEventListener: sinon.stub(),
+        removeEventListener: sinon.stub(),
+      },
+      eventSource: "TOP_STORIES",
+      options: { personalized: false },
+    };
+
+    function renderSection(props = {}) {
+      return shallow(<Section {...FAKE_TOPSTORIES_SECTION_PROPS} {...props} />);
+    }
+
+    it("should send impression with the right stats when the page loads", () => {
+      const dispatch = sinon.spy();
+      renderSection({ dispatch });
+
+      assert.calledOnce(dispatch);
+
+      const [action] = dispatch.firstCall.args;
+      assert.equal(action.type, at.TELEMETRY_IMPRESSION_STATS);
+      assert.equal(action.data.source, "TOP_STORIES");
+      assert.deepEqual(action.data.tiles, [{ id: 1 }, { id: 2 }]);
+    });
+    it("should not send impression stats if not configured", () => {
+      const dispatch = sinon.spy();
+      const props = Object.assign({}, FAKE_TOPSTORIES_SECTION_PROPS, {
+        shouldSendImpressionStats: false,
+        dispatch,
+      });
+      renderSection(props);
+      assert.notCalled(dispatch);
+    });
+    it("should not send impression stats if the section is collapsed", () => {
+      const dispatch = sinon.spy();
+      const props = Object.assign({}, FAKE_TOPSTORIES_SECTION_PROPS, {
+        pref: { collapsed: true },
+      });
+      renderSection(props);
+      assert.notCalled(dispatch);
+    });
+    it("should send 1 impression when the page becomes visibile after loading", () => {
+      const props = {
+        dispatch: sinon.spy(),
+        document: {
+          visibilityState: "hidden",
+          addEventListener: sinon.spy(),
+          removeEventListener: sinon.spy(),
+        },
+      };
+
+      renderSection(props);
+
+      // Was the event listener added?
+      assert.calledWith(props.document.addEventListener, "visibilitychange");
+
+      // Make sure dispatch wasn't called yet
+      assert.notCalled(props.dispatch);
+
+      // Simulate a visibilityChange event
+      const [, listener] = props.document.addEventListener.firstCall.args;
+      props.document.visibilityState = "visible";
+      listener();
+
+      // Did we actually dispatch an event?
+      assert.calledOnce(props.dispatch);
+      assert.equal(
+        props.dispatch.firstCall.args[0].type,
+        at.TELEMETRY_IMPRESSION_STATS
+      );
+
+      // Did we remove the event listener?
+      assert.calledWith(
+        props.document.removeEventListener,
+        "visibilitychange",
+        listener
+      );
+    });
+    it("should remove visibility change listener when section is removed", () => {
+      const props = {
+        dispatch: sinon.spy(),
+        document: {
+          visibilityState: "hidden",
+          addEventListener: sinon.spy(),
+          removeEventListener: sinon.spy(),
+        },
+      };
+
+      const section = renderSection(props);
+      assert.calledWith(props.document.addEventListener, "visibilitychange");
+      const [, listener] = props.document.addEventListener.firstCall.args;
+
+      section.unmount();
+      assert.calledWith(
+        props.document.removeEventListener,
+        "visibilitychange",
+        listener
+      );
+    });
+    it("should send an impression if props are updated and props.rows are different", () => {
+      const props = { dispatch: sinon.spy() };
+      wrapper = renderSection(props);
+      props.dispatch.resetHistory();
+
+      // New rows
+      wrapper.setProps(
+        Object.assign({}, FAKE_TOPSTORIES_SECTION_PROPS, {
+          rows: [{ guid: 123 }],
+        })
+      );
+
+      assert.calledOnce(props.dispatch);
+    });
+    it("should not send an impression if props are updated but props.rows are the same", () => {
+      const props = { dispatch: sinon.spy() };
+      wrapper = renderSection(props);
+      props.dispatch.resetHistory();
+
+      // Only update the disclaimer prop
+      wrapper.setProps(
+        Object.assign({}, FAKE_TOPSTORIES_SECTION_PROPS, {
+          disclaimer: { id: "bar" },
+        })
+      );
+
+      assert.notCalled(props.dispatch);
+    });
+    it("should not send an impression if props are updated and props.rows are the same but section is collapsed", () => {
+      const props = { dispatch: sinon.spy() };
+      wrapper = renderSection(props);
+      props.dispatch.resetHistory();
+
+      // New rows and collapsed
+      wrapper.setProps(
+        Object.assign({}, FAKE_TOPSTORIES_SECTION_PROPS, {
+          rows: [{ guid: 123 }],
+          pref: { collapsed: true },
+        })
+      );
+
+      assert.notCalled(props.dispatch);
+
+      // Expand the section. Now the impression stats should be sent
+      wrapper.setProps(
+        Object.assign({}, FAKE_TOPSTORIES_SECTION_PROPS, {
+          rows: [{ guid: 123 }],
+          pref: { collapsed: false },
+        })
+      );
+
+      assert.calledOnce(props.dispatch);
+    });
+    it("should not send an impression if props are updated but GUIDs are the same", () => {
+      const props = { dispatch: sinon.spy() };
+      wrapper = renderSection(props);
+      props.dispatch.resetHistory();
+
+      wrapper.setProps(
+        Object.assign({}, FAKE_TOPSTORIES_SECTION_PROPS, {
+          rows: [{ guid: 1 }, { guid: 2 }],
+        })
+      );
+
+      assert.notCalled(props.dispatch);
+    });
+    it("should only send the latest impression on a visibility change", () => {
+      const listeners = new Set();
+      const props = {
+        dispatch: sinon.spy(),
+        document: {
+          visibilityState: "hidden",
+          addEventListener: (ev, cb) => listeners.add(cb),
+          removeEventListener: (ev, cb) => listeners.delete(cb),
+        },
+      };
+
+      wrapper = renderSection(props);
+
+      // Update twice
+      wrapper.setProps(Object.assign({}, props, { rows: [{ guid: 123 }] }));
+      wrapper.setProps(Object.assign({}, props, { rows: [{ guid: 2432 }] }));
+
+      assert.notCalled(props.dispatch);
+
+      // Simulate listeners getting called
+      props.document.visibilityState = "visible";
+      listeners.forEach(l => l());
+
+      // Make sure we only sent the latest event
+      assert.calledOnce(props.dispatch);
+      const [action] = props.dispatch.firstCall.args;
+      assert.deepEqual(action.data.tiles, [{ id: 2432 }]);
+    });
+  });
+
+  describe("tab rehydrated", () => {
+    it("should fire NEW_TAB_REHYDRATED event", () => {
+      const dispatch = sinon.spy();
+      const TOP_STORIES_SECTION = {
+        id: "topstories",
+        title: "TopStories",
+        pref: { collapsed: false },
+        initialized: false,
+        rows: [{ guid: 1, link: "http://localhost", isDefault: true }],
+        topics: [],
+        read_more_endpoint: "http://localhost/read-more",
+        maxRows: 1,
+        eventSource: "TOP_STORIES",
+      };
+      wrapper = shallow(
+        <Section
+          Pocket={{ waitingForSpoc: true, pocketCta: {} }}
+          {...TOP_STORIES_SECTION}
+          dispatch={dispatch}
+        />
+      );
+      assert.notCalled(dispatch);
+
+      wrapper.setProps({ initialized: true });
+
+      assert.calledOnce(dispatch);
+      const [action] = dispatch.firstCall.args;
+      assert.equal("NEW_TAB_REHYDRATED", action.type);
+    });
+  });
+
+  describe("#numRows", () => {
+    it("should return maxRows if there is no rowsPref set", () => {
+      delete FAKE_SECTION.rowsPref;
+      wrapper = mountSectionIntlWithProps(FAKE_SECTION);
+      assert.equal(
+        wrapper.find(Section).instance().numRows,
+        FAKE_SECTION.maxRows
+      );
+    });
+
+    it("should return number of rows set in Pref if rowsPref is set", () => {
+      const numRows = 2;
+      Object.assign(FAKE_SECTION, {
+        rowsPref: "section.rows",
+        maxRows: 4,
+        Prefs: { values: { "section.rows": numRows } },
+      });
+      wrapper = mountSectionWithProps(FAKE_SECTION);
+      assert.equal(wrapper.find(Section).instance().numRows, numRows);
+    });
+
+    it("should return number of rows set in Pref even if higher than maxRows value", () => {
+      const numRows = 10;
+      Object.assign(FAKE_SECTION, {
+        rowsPref: "section.rows",
+        maxRows: 4,
+        Prefs: { values: { "section.rows": numRows } },
+      });
+      wrapper = mountSectionWithProps(FAKE_SECTION);
+      assert.equal(wrapper.find(Section).instance().numRows, numRows);
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/TopSites.test.jsx b/browser/components/newtab/test/unit/content-src/components/TopSites.test.jsx
new file mode 100644
index 0000000000..1977066f0d
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/TopSites.test.jsx
@@ -0,0 +1,1930 @@
+import {
+  actionCreators as ac,
+  actionTypes as at,
+} from "common/Actions.sys.mjs";
+import { GlobalOverrider } from "test/unit/utils";
+import { MIN_RICH_FAVICON_SIZE } from "content-src/components/TopSites/TopSitesConstants";
+import {
+  TOP_SITES_DEFAULT_ROWS,
+  TOP_SITES_MAX_SITES_PER_ROW,
+} from "common/Reducers.sys.mjs";
+import {
+  TopSite,
+  TopSiteLink,
+  _TopSiteList as TopSiteList,
+  TopSitePlaceholder,
+} from "content-src/components/TopSites/TopSite";
+import {
+  INTERSECTION_RATIO,
+  TopSiteImpressionWrapper,
+} from "content-src/components/TopSites/TopSiteImpressionWrapper";
+import { A11yLinkButton } from "content-src/components/A11yLinkButton/A11yLinkButton";
+import { LinkMenu } from "content-src/components/LinkMenu/LinkMenu";
+import React from "react";
+import { mount, shallow } from "enzyme";
+import { TopSiteForm } from "content-src/components/TopSites/TopSiteForm";
+import { TopSiteFormInput } from "content-src/components/TopSites/TopSiteFormInput";
+import { _TopSites as TopSites } from "content-src/components/TopSites/TopSites";
+import { ContextMenuButton } from "content-src/components/ContextMenu/ContextMenuButton";
+
+const perfSvc = {
+  mark() {},
+  getMostRecentAbsMarkStartByName() {},
+};
+
+const DEFAULT_PROPS = {
+  Prefs: { values: { featureConfig: {} } },
+  TopSites: { initialized: true, rows: [] },
+  TopSitesRows: TOP_SITES_DEFAULT_ROWS,
+  topSiteIconType: () => "no_image",
+  dispatch() {},
+  perfSvc,
+};
+
+const DEFAULT_BLOB_URL = "blob://test";
+
+describe("<TopSites>", () => {
+  let sandbox;
+
+  beforeEach(() => {
+    sandbox = sinon.createSandbox();
+  });
+
+  afterEach(() => {
+    sandbox.restore();
+  });
+
+  it("should render a TopSites element", () => {
+    const wrapper = shallow(<TopSites {...DEFAULT_PROPS} />);
+    assert.ok(wrapper.exists());
+  });
+  describe("#_dispatchTopSitesStats", () => {
+    let globals;
+    let wrapper;
+    let dispatchStatsSpy;
+
+    beforeEach(() => {
+      globals = new GlobalOverrider();
+      sandbox.stub(DEFAULT_PROPS, "dispatch");
+      wrapper = shallow(<TopSites {...DEFAULT_PROPS} />, {
+        disableLifecycleMethods: true,
+      });
+      dispatchStatsSpy = sandbox.spy(
+        wrapper.instance(),
+        "_dispatchTopSitesStats"
+      );
+    });
+    afterEach(() => {
+      globals.restore();
+      sandbox.restore();
+    });
+    it("should call _dispatchTopSitesStats on componentDidMount", () => {
+      wrapper.instance().componentDidMount();
+
+      assert.calledOnce(dispatchStatsSpy);
+    });
+    it("should call _dispatchTopSitesStats on componentDidUpdate", () => {
+      wrapper.instance().componentDidUpdate();
+
+      assert.calledOnce(dispatchStatsSpy);
+    });
+    it("should dispatch SAVE_SESSION_PERF_DATA", () => {
+      wrapper.instance()._dispatchTopSitesStats();
+
+      assert.calledOnce(DEFAULT_PROPS.dispatch);
+      assert.calledWithExactly(
+        DEFAULT_PROPS.dispatch,
+        ac.AlsoToMain({
+          type: at.SAVE_SESSION_PERF_DATA,
+          data: {
+            topsites_icon_stats: {
+              custom_screenshot: 0,
+              screenshot: 0,
+              tippytop: 0,
+              rich_icon: 0,
+              no_image: 0,
+            },
+            topsites_pinned: 0,
+            topsites_search_shortcuts: 0,
+          },
+        })
+      );
+    });
+    it("should correctly count TopSite images - just screenshot", () => {
+      const rows = [{ screenshot: true }];
+      sandbox.stub(DEFAULT_PROPS.TopSites, "rows").value(rows);
+      wrapper.instance()._dispatchTopSitesStats();
+
+      assert.calledOnce(DEFAULT_PROPS.dispatch);
+      assert.calledWithExactly(
+        DEFAULT_PROPS.dispatch,
+        ac.AlsoToMain({
+          type: at.SAVE_SESSION_PERF_DATA,
+          data: {
+            topsites_icon_stats: {
+              custom_screenshot: 0,
+              screenshot: 1,
+              tippytop: 0,
+              rich_icon: 0,
+              no_image: 0,
+            },
+            topsites_pinned: 0,
+            topsites_search_shortcuts: 0,
+          },
+        })
+      );
+    });
+    it("should correctly count TopSite images - custom_screenshot", () => {
+      const rows = [{ customScreenshotURL: true }];
+      sandbox.stub(DEFAULT_PROPS.TopSites, "rows").value(rows);
+      wrapper.instance()._dispatchTopSitesStats();
+
+      assert.calledOnce(DEFAULT_PROPS.dispatch);
+      assert.calledWithExactly(
+        DEFAULT_PROPS.dispatch,
+        ac.AlsoToMain({
+          type: at.SAVE_SESSION_PERF_DATA,
+          data: {
+            topsites_icon_stats: {
+              custom_screenshot: 1,
+              screenshot: 0,
+              tippytop: 0,
+              rich_icon: 0,
+              no_image: 0,
+            },
+            topsites_pinned: 0,
+            topsites_search_shortcuts: 0,
+          },
+        })
+      );
+    });
+    it("should correctly count TopSite images - rich_icon", () => {
+      const rows = [{ faviconSize: MIN_RICH_FAVICON_SIZE }];
+      sandbox.stub(DEFAULT_PROPS.TopSites, "rows").value(rows);
+      wrapper.instance()._dispatchTopSitesStats();
+
+      assert.calledOnce(DEFAULT_PROPS.dispatch);
+      assert.calledWithExactly(
+        DEFAULT_PROPS.dispatch,
+        ac.AlsoToMain({
+          type: at.SAVE_SESSION_PERF_DATA,
+          data: {
+            topsites_icon_stats: {
+              custom_screenshot: 0,
+              screenshot: 0,
+              tippytop: 0,
+              rich_icon: 1,
+              no_image: 0,
+            },
+            topsites_pinned: 0,
+            topsites_search_shortcuts: 0,
+          },
+        })
+      );
+    });
+    it("should correctly count TopSite images - tippytop", () => {
+      const rows = [
+        { tippyTopIcon: "foo" },
+        { faviconRef: "tippytop" },
+        { faviconRef: "foobar" },
+      ];
+      sandbox.stub(DEFAULT_PROPS.TopSites, "rows").value(rows);
+      wrapper.instance()._dispatchTopSitesStats();
+
+      assert.calledOnce(DEFAULT_PROPS.dispatch);
+      assert.calledWithExactly(
+        DEFAULT_PROPS.dispatch,
+        ac.AlsoToMain({
+          type: at.SAVE_SESSION_PERF_DATA,
+          data: {
+            topsites_icon_stats: {
+              custom_screenshot: 0,
+              screenshot: 0,
+              tippytop: 2,
+              rich_icon: 0,
+              no_image: 1,
+            },
+            topsites_pinned: 0,
+            topsites_search_shortcuts: 0,
+          },
+        })
+      );
+    });
+    it("should correctly count TopSite images - no image", () => {
+      const rows = [{}];
+      sandbox.stub(DEFAULT_PROPS.TopSites, "rows").value(rows);
+      wrapper.instance()._dispatchTopSitesStats();
+
+      assert.calledOnce(DEFAULT_PROPS.dispatch);
+      assert.calledWithExactly(
+        DEFAULT_PROPS.dispatch,
+        ac.AlsoToMain({
+          type: at.SAVE_SESSION_PERF_DATA,
+          data: {
+            topsites_icon_stats: {
+              custom_screenshot: 0,
+              screenshot: 0,
+              tippytop: 0,
+              rich_icon: 0,
+              no_image: 1,
+            },
+            topsites_pinned: 0,
+            topsites_search_shortcuts: 0,
+          },
+        })
+      );
+    });
+    it("should correctly count pinned Top Sites", () => {
+      const rows = [
+        { isPinned: true },
+        { isPinned: false },
+        { isPinned: true },
+      ];
+      sandbox.stub(DEFAULT_PROPS.TopSites, "rows").value(rows);
+      wrapper.instance()._dispatchTopSitesStats();
+
+      assert.calledOnce(DEFAULT_PROPS.dispatch);
+      assert.calledWithExactly(
+        DEFAULT_PROPS.dispatch,
+        ac.AlsoToMain({
+          type: at.SAVE_SESSION_PERF_DATA,
+          data: {
+            topsites_icon_stats: {
+              custom_screenshot: 0,
+              screenshot: 0,
+              tippytop: 0,
+              rich_icon: 0,
+              no_image: 3,
+            },
+            topsites_pinned: 2,
+            topsites_search_shortcuts: 0,
+          },
+        })
+      );
+    });
+    it("should correctly count search shortcut Top Sites", () => {
+      const rows = [{ searchTopSite: true }, { searchTopSite: true }];
+      sandbox.stub(DEFAULT_PROPS.TopSites, "rows").value(rows);
+      wrapper.instance()._dispatchTopSitesStats();
+
+      assert.calledOnce(DEFAULT_PROPS.dispatch);
+      assert.calledWithExactly(
+        DEFAULT_PROPS.dispatch,
+        ac.AlsoToMain({
+          type: at.SAVE_SESSION_PERF_DATA,
+          data: {
+            topsites_icon_stats: {
+              custom_screenshot: 0,
+              screenshot: 0,
+              tippytop: 0,
+              rich_icon: 0,
+              no_image: 2,
+            },
+            topsites_pinned: 0,
+            topsites_search_shortcuts: 2,
+          },
+        })
+      );
+    });
+    it("should only count visible top sites on wide layout", () => {
+      globals.set("matchMedia", () => ({ matches: true }));
+      const rows = [
+        {},
+        {},
+        {},
+        {},
+        {},
+        {},
+        {},
+        {},
+        {},
+        {},
+        {},
+        {},
+        {},
+        {},
+        {},
+        {},
+      ];
+      sandbox.stub(DEFAULT_PROPS.TopSites, "rows").value(rows);
+
+      wrapper.instance()._dispatchTopSitesStats();
+      assert.calledOnce(DEFAULT_PROPS.dispatch);
+      assert.calledWithExactly(
+        DEFAULT_PROPS.dispatch,
+        ac.AlsoToMain({
+          type: at.SAVE_SESSION_PERF_DATA,
+          data: {
+            topsites_icon_stats: {
+              custom_screenshot: 0,
+              screenshot: 0,
+              tippytop: 0,
+              rich_icon: 0,
+              no_image: 8,
+            },
+            topsites_pinned: 0,
+            topsites_search_shortcuts: 0,
+          },
+        })
+      );
+    });
+    it("should only count visible top sites on normal layout", () => {
+      globals.set("matchMedia", () => ({ matches: false }));
+      const rows = [
+        {},
+        {},
+        {},
+        {},
+        {},
+        {},
+        {},
+        {},
+        {},
+        {},
+        {},
+        {},
+        {},
+        {},
+        {},
+        {},
+      ];
+      sandbox.stub(DEFAULT_PROPS.TopSites, "rows").value(rows);
+      wrapper.instance()._dispatchTopSitesStats();
+      assert.calledOnce(DEFAULT_PROPS.dispatch);
+      assert.calledWithExactly(
+        DEFAULT_PROPS.dispatch,
+        ac.AlsoToMain({
+          type: at.SAVE_SESSION_PERF_DATA,
+          data: {
+            topsites_icon_stats: {
+              custom_screenshot: 0,
+              screenshot: 0,
+              tippytop: 0,
+              rich_icon: 0,
+              no_image: 6,
+            },
+            topsites_pinned: 0,
+            topsites_search_shortcuts: 0,
+          },
+        })
+      );
+    });
+  });
+});
+
+describe("<TopSiteLink>", () => {
+  let globals;
+  let link;
+  let url;
+  beforeEach(() => {
+    globals = new GlobalOverrider();
+    url = {
+      createObjectURL: globals.sandbox.stub().returns(DEFAULT_BLOB_URL),
+      revokeObjectURL: globals.sandbox.spy(),
+    };
+    globals.set("URL", url);
+    link = { url: "https://foo.com", screenshot: "foo.jpg", hostname: "foo" };
+  });
+  afterEach(() => globals.restore());
+  it("should add the right url", () => {
+    link.url = "https://www.foobar.org";
+    const wrapper = shallow(<TopSiteLink link={link} />);
+    assert.propertyVal(
+      wrapper.find("a").props(),
+      "href",
+      "https://www.foobar.org"
+    );
+  });
+  it("should not add the url to the href if it a search shortcut", () => {
+    link.searchTopSite = true;
+    const wrapper = shallow(<TopSiteLink link={link} />);
+    assert.isUndefined(wrapper.find("a").props().href);
+  });
+  it("should have rtl direction automatically set for text", () => {
+    const wrapper = shallow(<TopSiteLink link={link} />);
+
+    assert.isTrue(!!wrapper.find("[dir='auto']").length);
+  });
+  it("should render a title", () => {
+    const wrapper = shallow(<TopSiteLink link={link} title="foobar" />);
+    const titleEl = wrapper.find(".title");
+
+    assert.equal(titleEl.text(), "foobar");
+  });
+  it("should have only the title as the text of the link", () => {
+    const wrapper = shallow(<TopSiteLink link={link} title="foobar" />);
+
+    assert.equal(wrapper.find("a").text(), "foobar");
+  });
+  it("should render the pin icon for pinned links", () => {
+    link.isPinned = true;
+    link.pinnedIndex = 7;
+    const wrapper = shallow(<TopSiteLink link={link} />);
+    assert.equal(wrapper.find(".icon-pin-small").length, 1);
+  });
+  it("should not render the pin icon for non pinned links", () => {
+    link.isPinned = false;
+    const wrapper = shallow(<TopSiteLink link={link} />);
+    assert.equal(wrapper.find(".icon-pin-small").length, 0);
+  });
+  it("should render the first letter of the title as a fallback for missing icons", () => {
+    const wrapper = shallow(<TopSiteLink link={link} title={"foo"} />);
+    assert.equal(wrapper.find(".icon-wrapper").prop("data-fallback"), "f");
+  });
+  it("should render the tippy top icon if provided and not a small icon", () => {
+    link.tippyTopIcon = "foo.png";
+    link.backgroundColor = "#FFFFFF";
+    const wrapper = shallow(<TopSiteLink link={link} />);
+    assert.lengthOf(wrapper.find(".screenshot"), 0);
+    assert.lengthOf(wrapper.find(".default-icon"), 0);
+    const tippyTop = wrapper.find(".rich-icon");
+    assert.propertyVal(
+      tippyTop.props().style,
+      "backgroundImage",
+      "url(foo.png)"
+    );
+    assert.propertyVal(tippyTop.props().style, "backgroundColor", "#FFFFFF");
+  });
+  it("should render a rich icon if provided and not a small icon", () => {
+    link.favicon = "foo.png";
+    link.faviconSize = 196;
+    link.backgroundColor = "#FFFFFF";
+    const wrapper = shallow(<TopSiteLink link={link} />);
+    assert.lengthOf(wrapper.find(".screenshot"), 0);
+    assert.lengthOf(wrapper.find(".default-icon"), 0);
+    const richIcon = wrapper.find(".rich-icon");
+    assert.propertyVal(
+      richIcon.props().style,
+      "backgroundImage",
+      "url(foo.png)"
+    );
+    assert.propertyVal(richIcon.props().style, "backgroundColor", "#FFFFFF");
+  });
+  it("should not render a rich icon if it is smaller than 96x96", () => {
+    link.favicon = "foo.png";
+    link.faviconSize = 48;
+    link.backgroundColor = "#FFFFFF";
+    const wrapper = shallow(<TopSiteLink link={link} />);
+    assert.lengthOf(wrapper.find(".default-icon"), 1);
+    assert.equal(wrapper.find(".rich-icon").length, 0);
+  });
+  it("should apply just the default class name to the outer link if props.className is falsey", () => {
+    const wrapper = shallow(<TopSiteLink className={false} />);
+    assert.ok(wrapper.find("li").hasClass("top-site-outer"));
+  });
+  it("should add props.className to the outer link element", () => {
+    const wrapper = shallow(<TopSiteLink className="foo bar" />);
+    assert.ok(wrapper.find("li").hasClass("top-site-outer foo bar"));
+  });
+  describe("#_allowDrop", () => {
+    let wrapper;
+    let event;
+    beforeEach(() => {
+      event = {
+        dataTransfer: {
+          types: ["text/topsite-index"],
+        },
+      };
+      wrapper = shallow(
+        <TopSiteLink isDraggable={true} onDragEvent={() => {}} />
+      );
+    });
+    it("should be droppable for basic case", () => {
+      const result = wrapper.instance()._allowDrop(event);
+      assert.isTrue(result);
+    });
+    it("should not be droppable for sponsored_position", () => {
+      wrapper.setProps({ link: { sponsored_position: 1 } });
+      const result = wrapper.instance()._allowDrop(event);
+      assert.isFalse(result);
+    });
+    it("should not be droppable for link.type", () => {
+      wrapper.setProps({ link: { type: "SPOC" } });
+      const result = wrapper.instance()._allowDrop(event);
+      assert.isFalse(result);
+    });
+  });
+  describe("#onDragEvent", () => {
+    let simulate;
+    let wrapper;
+    beforeEach(() => {
+      wrapper = shallow(
+        <TopSiteLink isDraggable={true} onDragEvent={() => {}} />
+      );
+      simulate = type => {
+        const event = {
+          dataTransfer: { setData() {}, types: { includes() {} } },
+          preventDefault() {
+            this.prevented = true;
+          },
+          target: { blur() {} },
+          type,
+        };
+        wrapper.simulate(type, event);
+        return event;
+      };
+    });
+    it("should allow clicks without dragging", () => {
+      simulate("mousedown");
+      simulate("mouseup");
+
+      const event = simulate("click");
+
+      assert.notOk(event.prevented);
+    });
+    it("should prevent clicks after dragging", () => {
+      simulate("mousedown");
+      simulate("dragstart");
+      simulate("dragenter");
+      simulate("drop");
+      simulate("dragend");
+      simulate("mouseup");
+
+      const event = simulate("click");
+
+      assert.ok(event.prevented);
+    });
+    it("should allow clicks after dragging then clicking", () => {
+      simulate("mousedown");
+      simulate("dragstart");
+      simulate("dragenter");
+      simulate("drop");
+      simulate("dragend");
+      simulate("mouseup");
+      simulate("click");
+
+      simulate("mousedown");
+      simulate("mouseup");
+
+      const event = simulate("click");
+
+      assert.notOk(event.prevented);
+    });
+    it("should prevent dragging with sponsored_position from dragstart", () => {
+      const preventDefault = sinon.stub();
+      const blur = sinon.stub();
+      wrapper.setProps({ link: { sponsored_position: 1 } });
+      wrapper.instance().onDragEvent({
+        type: "dragstart",
+        preventDefault,
+        target: { blur },
+      });
+      assert.calledOnce(preventDefault);
+      assert.calledOnce(blur);
+      assert.isUndefined(wrapper.instance().dragged);
+    });
+    it("should prevent dragging with link.shim from dragstart", () => {
+      const preventDefault = sinon.stub();
+      const blur = sinon.stub();
+      wrapper.setProps({ link: { type: "SPOC" } });
+      wrapper.instance().onDragEvent({
+        type: "dragstart",
+        preventDefault,
+        target: { blur },
+      });
+      assert.calledOnce(preventDefault);
+      assert.calledOnce(blur);
+      assert.isUndefined(wrapper.instance().dragged);
+    });
+  });
+
+  describe("#generateColor", () => {
+    let colors;
+    beforeEach(() => {
+      colors = "#0090ED,#FF4F5F,#2AC3A2";
+    });
+
+    it("should generate a random color but always pick the same color for the same string", async () => {
+      let wrapper = shallow(
+        <TopSiteLink colors={colors} title={"food"} link={link} />
+      );
+
+      assert.equal(wrapper.find(".icon-wrapper").prop("data-fallback"), "f");
+      assert.equal(
+        wrapper.find(".icon-wrapper").prop("style").backgroundColor,
+        colors.split(",")[1]
+      );
+      assert.ok(true);
+    });
+
+    it("should generate a different random color", async () => {
+      let wrapper = shallow(
+        <TopSiteLink colors={colors} title={"fam"} link={link} />
+      );
+
+      assert.equal(
+        wrapper.find(".icon-wrapper").prop("style").backgroundColor,
+        colors.split(",")[2]
+      );
+      assert.ok(true);
+    });
+
+    it("should generate a third random color", async () => {
+      let wrapper = shallow(<TopSiteLink colors={colors} title={"foo"} />);
+
+      assert.equal(wrapper.find(".icon-wrapper").prop("data-fallback"), "f");
+      assert.equal(
+        wrapper.find(".icon-wrapper").prop("style").backgroundColor,
+        colors.split(",")[0]
+      );
+      assert.ok(true);
+    });
+  });
+});
+
+describe("<TopSite>", () => {
+  let link;
+  beforeEach(() => {
+    link = { url: "https://foo.com", screenshot: "foo.jpg", hostname: "foo" };
+  });
+
+  // Build IntersectionObserver class with the arg `entries` for the intersect callback.
+  function buildIntersectionObserver(entries) {
+    return class {
+      constructor(callback) {
+        this.callback = callback;
+      }
+
+      observe() {
+        this.callback(entries);
+      }
+
+      unobserve() {}
+    };
+  }
+
+  it("should render a TopSite", () => {
+    const wrapper = shallow(<TopSite link={link} />);
+    assert.ok(wrapper.exists());
+  });
+
+  it("should render a shortened title based off the url", () => {
+    link.url = "https://www.foobar.org";
+    link.hostname = "foobar";
+    link.eTLD = "org";
+    const wrapper = shallow(<TopSite link={link} />);
+
+    assert.equal(wrapper.find(TopSiteLink).props().title, "foobar");
+  });
+
+  it("should parse args for fluent correctly", () => {
+    const title = '"fluent"';
+    link.hostname = title;
+
+    const wrapper = mount(<TopSite link={link} />);
+    const button = wrapper.find(
+      "button[data-l10n-id='newtab-menu-content-tooltip']"
+    );
+    assert.equal(button.prop("data-l10n-args"), JSON.stringify({ title }));
+  });
+
+  it("should have .active class, on top-site-outer if context menu is open", () => {
+    const wrapper = shallow(<TopSite link={link} index={1} activeIndex={1} />);
+    wrapper.setState({ showContextMenu: true });
+
+    assert.equal(wrapper.find(TopSiteLink).props().className.trim(), "active");
+  });
+  it("should not add .active class, on top-site-outer if context menu is closed", () => {
+    const wrapper = shallow(<TopSite link={link} index={1} />);
+    wrapper.setState({ showContextMenu: false, activeTile: 1 });
+    assert.equal(wrapper.find(TopSiteLink).props().className, "");
+  });
+  it("should render a context menu button", () => {
+    const wrapper = shallow(<TopSite link={link} />);
+    assert.equal(wrapper.find(ContextMenuButton).length, 1);
+  });
+  it("should render a link menu", () => {
+    const wrapper = shallow(<TopSite link={link} />);
+    assert.equal(wrapper.find(LinkMenu).length, 1);
+  });
+  it("should pass onUpdate, site, options, and index to LinkMenu", () => {
+    const wrapper = shallow(<TopSite link={link} />);
+    const linkMenuProps = wrapper.find(LinkMenu).props();
+    ["onUpdate", "site", "index", "options"].forEach(prop =>
+      assert.property(linkMenuProps, prop)
+    );
+  });
+  it("should pass through the correct menu options to LinkMenu", () => {
+    const wrapper = shallow(<TopSite link={link} />);
+    const linkMenuProps = wrapper.find(LinkMenu).props();
+    assert.deepEqual(linkMenuProps.options, [
+      "CheckPinTopSite",
+      "EditTopSite",
+      "Separator",
+      "OpenInNewWindow",
+      "OpenInPrivateWindow",
+      "Separator",
+      "BlockUrl",
+      "DeleteUrl",
+    ]);
+  });
+  it("should record impressions for visible organic Top Sites", () => {
+    const dispatch = sinon.stub();
+    const wrapper = shallow(
+      <TopSite
+        link={link}
+        index={3}
+        dispatch={dispatch}
+        IntersectionObserver={buildIntersectionObserver([
+          {
+            isIntersecting: true,
+            intersectionRatio: INTERSECTION_RATIO,
+          },
+        ])}
+        document={{
+          visibilityState: "visible",
+          addEventListener: sinon.stub(),
+          removeEventListener: sinon.stub(),
+        }}
+      />
+    );
+    const linkWrapper = wrapper.find(TopSiteLink).dive();
+    assert.ok(linkWrapper.exists());
+    const impressionWrapper = linkWrapper.find(TopSiteImpressionWrapper).dive();
+    assert.ok(impressionWrapper.exists());
+
+    assert.calledOnce(dispatch);
+
+    let [action] = dispatch.firstCall.args;
+    assert.equal(action.type, at.TOP_SITES_ORGANIC_IMPRESSION_STATS);
+
+    assert.propertyVal(action.data, "type", "impression");
+    assert.propertyVal(action.data, "source", "newtab");
+    assert.propertyVal(action.data, "position", 3);
+  });
+  it("should record impressions for visible sponsored Top Sites", () => {
+    const dispatch = sinon.stub();
+    const wrapper = shallow(
+      <TopSite
+        link={Object.assign({}, link, {
+          sponsored_position: 2,
+          sponsored_tile_id: 12345,
+          sponsored_impression_url: "http://impression.example.com/",
+        })}
+        index={3}
+        dispatch={dispatch}
+        IntersectionObserver={buildIntersectionObserver([
+          {
+            isIntersecting: true,
+            intersectionRatio: INTERSECTION_RATIO,
+          },
+        ])}
+        document={{
+          visibilityState: "visible",
+          addEventListener: sinon.stub(),
+          removeEventListener: sinon.stub(),
+        }}
+      />
+    );
+    const linkWrapper = wrapper.find(TopSiteLink).dive();
+    assert.ok(linkWrapper.exists());
+    const impressionWrapper = linkWrapper.find(TopSiteImpressionWrapper).dive();
+    assert.ok(impressionWrapper.exists());
+
+    assert.calledOnce(dispatch);
+
+    let [action] = dispatch.firstCall.args;
+    assert.equal(action.type, at.TOP_SITES_SPONSORED_IMPRESSION_STATS);
+
+    assert.propertyVal(action.data, "type", "impression");
+    assert.propertyVal(action.data, "tile_id", 12345);
+    assert.propertyVal(action.data, "source", "newtab");
+    assert.propertyVal(action.data, "position", 3);
+    assert.propertyVal(
+      action.data,
+      "reporting_url",
+      "http://impression.example.com/"
+    );
+    assert.propertyVal(action.data, "advertiser", "foo");
+  });
+
+  describe("#onLinkClick", () => {
+    it("should call dispatch when the link is clicked", () => {
+      const dispatch = sinon.stub();
+      const wrapper = shallow(
+        <TopSite link={link} index={3} dispatch={dispatch} />
+      );
+
+      wrapper.find(TopSiteLink).simulate("click", { preventDefault() {} });
+
+      let [action] = dispatch.firstCall.args;
+      assert.isUserEventAction(action);
+
+      assert.propertyVal(action.data, "event", "CLICK");
+      assert.propertyVal(action.data, "source", "TOP_SITES");
+      assert.propertyVal(action.data, "action_position", 3);
+
+      [action] = dispatch.secondCall.args;
+      assert.propertyVal(action, "type", at.OPEN_LINK);
+
+      // Organic Top Site click event.
+      [action] = dispatch.thirdCall.args;
+      assert.equal(action.type, at.TOP_SITES_ORGANIC_IMPRESSION_STATS);
+
+      assert.propertyVal(action.data, "type", "click");
+      assert.propertyVal(action.data, "source", "newtab");
+      assert.propertyVal(action.data, "position", 3);
+    });
+    it("should dispatch a UserEventAction with the right data", () => {
+      const dispatch = sinon.stub();
+      const wrapper = shallow(
+        <TopSite
+          link={Object.assign({}, link, {
+            iconType: "rich_icon",
+            isPinned: true,
+          })}
+          index={3}
+          dispatch={dispatch}
+        />
+      );
+
+      wrapper.find(TopSiteLink).simulate("click", { preventDefault() {} });
+
+      const [action] = dispatch.firstCall.args;
+      assert.isUserEventAction(action);
+
+      assert.propertyVal(action.data, "event", "CLICK");
+      assert.propertyVal(action.data, "source", "TOP_SITES");
+      assert.propertyVal(action.data, "action_position", 3);
+      assert.propertyVal(action.data.value, "card_type", "pinned");
+      assert.propertyVal(action.data.value, "icon_type", "rich_icon");
+    });
+    it("should dispatch a UserEventAction with the right data for search top site", () => {
+      const dispatch = sinon.stub();
+      const siteInfo = {
+        iconType: "tippytop",
+        isPinned: true,
+        searchTopSite: true,
+        hostname: "google",
+        label: "@google",
+      };
+      const wrapper = shallow(
+        <TopSite
+          link={Object.assign({}, link, siteInfo)}
+          index={3}
+          dispatch={dispatch}
+        />
+      );
+
+      wrapper.find(TopSiteLink).simulate("click", { preventDefault() {} });
+
+      const [action] = dispatch.firstCall.args;
+      assert.isUserEventAction(action);
+
+      assert.propertyVal(action.data, "event", "CLICK");
+      assert.propertyVal(action.data, "source", "TOP_SITES");
+      assert.propertyVal(action.data, "action_position", 3);
+      assert.propertyVal(action.data.value, "card_type", "search");
+      assert.propertyVal(action.data.value, "icon_type", "tippytop");
+      assert.propertyVal(action.data.value, "search_vendor", "google");
+    });
+    it("should dispatch a UserEventAction with the right data for SPOC top site", () => {
+      const dispatch = sinon.stub();
+      const siteInfo = {
+        id: 1,
+        iconType: "custom_screenshot",
+        type: "SPOC",
+        pos: 1,
+        label: "test advertiser",
+        shim: { click: "shim_click_id" },
+      };
+      const wrapper = shallow(
+        <TopSite
+          link={Object.assign({}, link, siteInfo)}
+          index={0}
+          dispatch={dispatch}
+        />
+      );
+
+      wrapper.find(TopSiteLink).simulate("click", { preventDefault() {} });
+
+      let [action] = dispatch.firstCall.args;
+      assert.isUserEventAction(action);
+
+      assert.propertyVal(action.data, "event", "CLICK");
+      assert.propertyVal(action.data, "source", "TOP_SITES");
+      assert.propertyVal(action.data, "action_position", 0);
+      assert.propertyVal(action.data.value, "card_type", "spoc");
+      assert.propertyVal(action.data.value, "icon_type", "custom_screenshot");
+
+      // Pocket SPOC click event.
+      [action] = dispatch.getCall(2).args;
+      assert.equal(action.type, at.TELEMETRY_IMPRESSION_STATS);
+
+      assert.propertyVal(action.data, "click", 0);
+      assert.propertyVal(action.data, "source", "TOP_SITES");
+
+      [action] = dispatch.getCall(3).args;
+      assert.equal(action.type, at.DISCOVERY_STREAM_USER_EVENT);
+
+      assert.propertyVal(action.data, "event", "CLICK");
+      assert.propertyVal(action.data, "action_position", 1);
+      assert.propertyVal(action.data, "source", "TOP_SITES");
+      assert.propertyVal(action.data.value, "card_type", "spoc");
+      assert.propertyVal(action.data.value, "tile_id", 1);
+      assert.propertyVal(action.data.value, "shim", "shim_click_id");
+
+      // Topsite SPOC click event.
+      [action] = dispatch.getCall(4).args;
+      assert.equal(action.type, at.TOP_SITES_SPONSORED_IMPRESSION_STATS);
+
+      assert.propertyVal(action.data, "type", "click");
+      assert.propertyVal(action.data, "tile_id", 1);
+      assert.propertyVal(action.data, "source", "newtab");
+      assert.propertyVal(action.data, "position", 1);
+      assert.propertyVal(action.data, "advertiser", "test advertiser");
+    });
+    it("should dispatch OPEN_LINK with the right data", () => {
+      const dispatch = sinon.stub();
+      const wrapper = shallow(
+        <TopSite
+          link={Object.assign({}, link, { typedBonus: true })}
+          index={3}
+          dispatch={dispatch}
+        />
+      );
+
+      wrapper.find(TopSiteLink).simulate("click", { preventDefault() {} });
+
+      const [action] = dispatch.secondCall.args;
+      assert.propertyVal(action, "type", at.OPEN_LINK);
+      assert.propertyVal(action.data, "typedBonus", true);
+    });
+  });
+});
+
+describe("<TopSiteForm>", () => {
+  let wrapper;
+  let sandbox;
+
+  function setup(props = {}) {
+    sandbox = sinon.createSandbox();
+    const customProps = Object.assign(
+      {},
+      { onClose: sandbox.spy(), dispatch: sandbox.spy() },
+      props
+    );
+    wrapper = mount(<TopSiteForm {...customProps} />);
+  }
+
+  describe("validateForm", () => {
+    beforeEach(() => setup({ site: { url: "http://foo" } }));
+
+    it("should return true for a correct URL", () => {
+      wrapper.setState({ url: "foo" });
+
+      assert.isTrue(wrapper.instance().validateForm());
+    });
+
+    it("should return false for a incorrect URL", () => {
+      wrapper.setState({ url: " " });
+
+      assert.isNull(wrapper.instance().validateForm());
+      assert.isTrue(wrapper.state().validationError);
+    });
+
+    it("should return true for a correct custom screenshot URL", () => {
+      wrapper.setState({ customScreenshotUrl: "foo" });
+
+      assert.isTrue(wrapper.instance().validateForm());
+    });
+
+    it("should return false for a incorrect custom screenshot URL", () => {
+      wrapper.setState({ customScreenshotUrl: " " });
+
+      assert.isNull(wrapper.instance().validateForm());
+    });
+
+    it("should return true for an empty custom screenshot URL", () => {
+      wrapper.setState({ customScreenshotUrl: "" });
+
+      assert.isTrue(wrapper.instance().validateForm());
+    });
+
+    it("should return false for file: protocol", () => {
+      wrapper.setState({ customScreenshotUrl: "file:///C:/Users/foo" });
+
+      assert.isFalse(wrapper.instance().validateForm());
+    });
+  });
+
+  describe("#previewButton", () => {
+    beforeEach(() =>
+      setup({
+        site: { customScreenshotURL: "http://foo.com" },
+        previewResponse: null,
+      })
+    );
+
+    it("should render the preview button on invalid urls", () => {
+      assert.equal(0, wrapper.find(".preview").length);
+
+      wrapper.setState({ customScreenshotUrl: " " });
+
+      assert.equal(1, wrapper.find(".preview").length);
+    });
+
+    it("should render the preview button when input value updated", () => {
+      assert.equal(0, wrapper.find(".preview").length);
+
+      wrapper.setState({
+        customScreenshotUrl: "http://baz.com",
+        screenshotPreview: null,
+      });
+
+      assert.equal(1, wrapper.find(".preview").length);
+    });
+  });
+
+  describe("preview request", () => {
+    beforeEach(() => {
+      setup({
+        site: { customScreenshotURL: "http://foo.com", url: "http://foo.com" },
+        previewResponse: null,
+      });
+    });
+
+    it("shouldn't dispatch a request for invalid urls", () => {
+      wrapper.setState({ customScreenshotUrl: " ", url: "foo" });
+
+      wrapper.find(".preview").simulate("click");
+
+      assert.notCalled(wrapper.props().dispatch);
+    });
+
+    it("should dispatch a PREVIEW_REQUEST", () => {
+      wrapper.setState({ customScreenshotUrl: "screenshot" });
+      wrapper.find(".preview").simulate("submit");
+
+      assert.calledTwice(wrapper.props().dispatch);
+      assert.calledWith(
+        wrapper.props().dispatch,
+        ac.AlsoToMain({
+          type: at.PREVIEW_REQUEST,
+          data: { url: "http://screenshot" },
+        })
+      );
+      assert.calledWith(
+        wrapper.props().dispatch,
+        ac.UserEvent({
+          event: "PREVIEW_REQUEST",
+          source: "TOP_SITES",
+        })
+      );
+    });
+  });
+
+  describe("#TopSiteLink", () => {
+    beforeEach(() => {
+      setup();
+    });
+
+    it("should display a TopSiteLink preview", () => {
+      assert.equal(wrapper.find(TopSiteLink).length, 1);
+    });
+
+    it("should display an icon for tippyTop sites", () => {
+      wrapper.setProps({ site: { tippyTopIcon: "bar" } });
+
+      assert.equal(
+        wrapper.find(".top-site-icon").getDOMNode().style["background-image"],
+        'url("bar")'
+      );
+    });
+
+    it("should not display a preview screenshot", () => {
+      wrapper.setProps({ previewResponse: "foo", previewUrl: "foo" });
+
+      assert.lengthOf(wrapper.find(".screenshot"), 0);
+    });
+
+    it("should not render any icon on error", () => {
+      wrapper.setProps({ previewResponse: "" });
+
+      assert.equal(wrapper.find(".top-site-icon").length, 0);
+    });
+
+    it("should render the search icon when searchTopSite is true", () => {
+      wrapper.setProps({ site: { tippyTopIcon: "bar", searchTopSite: true } });
+
+      assert.equal(
+        wrapper.find(".rich-icon").getDOMNode().style["background-image"],
+        'url("bar")'
+      );
+      assert.isTrue(wrapper.find(".search-topsite").exists());
+    });
+  });
+
+  describe("#addMode", () => {
+    beforeEach(() => setup());
+
+    it("should render the component", () => {
+      assert.ok(wrapper.find(TopSiteForm).exists());
+    });
+    it("should have the correct header", () => {
+      assert.equal(
+        wrapper.findWhere(
+          n =>
+            n.length &&
+            n.prop("data-l10n-id") === "newtab-topsites-add-shortcut-header"
+        ).length,
+        1
+      );
+    });
+    it("should have the correct button text", () => {
+      assert.equal(
+        wrapper.findWhere(
+          n =>
+            n.length && n.prop("data-l10n-id") === "newtab-topsites-save-button"
+        ).length,
+        0
+      );
+      assert.equal(
+        wrapper.findWhere(
+          n =>
+            n.length && n.prop("data-l10n-id") === "newtab-topsites-add-button"
+        ).length,
+        1
+      );
+    });
+    it("should not render a preview button", () => {
+      assert.equal(0, wrapper.find(".custom-image-input-container").length);
+    });
+    it("should call onClose if Cancel button is clicked", () => {
+      wrapper.find(".cancel").simulate("click");
+      assert.calledOnce(wrapper.instance().props.onClose);
+    });
+    it("should set validationError if url is empty", () => {
+      assert.equal(wrapper.state().validationError, false);
+      wrapper.find(".done").simulate("submit");
+      assert.equal(wrapper.state().validationError, true);
+    });
+    it("should set validationError if url is invalid", () => {
+      wrapper.setState({ url: "not valid" });
+      assert.equal(wrapper.state().validationError, false);
+      wrapper.find(".done").simulate("submit");
+      assert.equal(wrapper.state().validationError, true);
+    });
+    it("should call onClose and dispatch with right args if URL is valid", () => {
+      wrapper.setState({ url: "valid.com", label: "a label" });
+      wrapper.find(".done").simulate("submit");
+      assert.calledOnce(wrapper.instance().props.onClose);
+      assert.calledWith(wrapper.instance().props.dispatch, {
+        data: {
+          site: { label: "a label", url: "http://valid.com" },
+          index: -1,
+        },
+        meta: { from: "ActivityStream:Content", to: "ActivityStream:Main" },
+        type: at.TOP_SITES_PIN,
+      });
+      assert.calledWith(wrapper.instance().props.dispatch, {
+        data: {
+          action_position: -1,
+          source: "TOP_SITES",
+          event: "TOP_SITES_EDIT",
+        },
+        meta: { from: "ActivityStream:Content", to: "ActivityStream:Main" },
+        type: at.TELEMETRY_USER_EVENT,
+      });
+    });
+    it("should not pass empty string label in dispatch data", () => {
+      wrapper.setState({ url: "valid.com", label: "" });
+      wrapper.find(".done").simulate("submit");
+      assert.calledWith(wrapper.instance().props.dispatch, {
+        data: { site: { url: "http://valid.com" }, index: -1 },
+        meta: { from: "ActivityStream:Content", to: "ActivityStream:Main" },
+        type: at.TOP_SITES_PIN,
+      });
+    });
+    it("should open the custom screenshot input", () => {
+      assert.isFalse(wrapper.state().showCustomScreenshotForm);
+
+      wrapper.find(A11yLinkButton).simulate("click");
+
+      assert.isTrue(wrapper.state().showCustomScreenshotForm);
+    });
+  });
+
+  describe("edit existing Topsite", () => {
+    beforeEach(() =>
+      setup({
+        site: {
+          url: "https://foo.bar",
+          label: "baz",
+          customScreenshotURL: "http://foo",
+        },
+        index: 7,
+      })
+    );
+
+    it("should render the component", () => {
+      assert.ok(wrapper.find(TopSiteForm).exists());
+    });
+    it("should have the correct header", () => {
+      assert.equal(
+        wrapper.findWhere(
+          n => n.prop("data-l10n-id") === "newtab-topsites-edit-shortcut-header"
+        ).length,
+        1
+      );
+    });
+    it("should have the correct button text", () => {
+      assert.equal(
+        wrapper.findWhere(
+          n => n.prop("data-l10n-id") === "newtab-topsites-add-button"
+        ).length,
+        0
+      );
+      assert.equal(
+        wrapper.findWhere(
+          n => n.prop("data-l10n-id") === "newtab-topsites-save-button"
+        ).length,
+        1
+      );
+    });
+    it("should call onClose if Cancel button is clicked", () => {
+      wrapper.find(".cancel").simulate("click");
+      assert.calledOnce(wrapper.instance().props.onClose);
+    });
+    it("should show error and not call onClose or dispatch if URL is empty", () => {
+      wrapper.setState({ url: "" });
+      assert.equal(wrapper.state().validationError, false);
+      wrapper.find(".done").simulate("submit");
+      assert.equal(wrapper.state().validationError, true);
+      assert.notCalled(wrapper.instance().props.onClose);
+      assert.notCalled(wrapper.instance().props.dispatch);
+    });
+    it("should show error and not call onClose or dispatch if URL is invalid", () => {
+      wrapper.setState({ url: "not valid" });
+      assert.equal(wrapper.state().validationError, false);
+      wrapper.find(".done").simulate("submit");
+      assert.equal(wrapper.state().validationError, true);
+      assert.notCalled(wrapper.instance().props.onClose);
+      assert.notCalled(wrapper.instance().props.dispatch);
+    });
+    it("should call onClose and dispatch with right args if URL is valid", () => {
+      wrapper.find(".done").simulate("submit");
+      assert.calledOnce(wrapper.instance().props.onClose);
+      assert.calledTwice(wrapper.instance().props.dispatch);
+      assert.calledWith(wrapper.instance().props.dispatch, {
+        data: {
+          site: {
+            label: "baz",
+            url: "https://foo.bar",
+            customScreenshotURL: "http://foo",
+          },
+          index: 7,
+        },
+        meta: { from: "ActivityStream:Content", to: "ActivityStream:Main" },
+        type: at.TOP_SITES_PIN,
+      });
+      assert.calledWith(wrapper.instance().props.dispatch, {
+        data: {
+          action_position: 7,
+          source: "TOP_SITES",
+          event: "TOP_SITES_EDIT",
+        },
+        meta: { from: "ActivityStream:Content", to: "ActivityStream:Main" },
+        type: at.TELEMETRY_USER_EVENT,
+      });
+    });
+    it("should set customScreenshotURL to null if it was removed", () => {
+      wrapper.setState({ customScreenshotUrl: "" });
+
+      wrapper.find(".done").simulate("submit");
+
+      assert.calledWith(wrapper.instance().props.dispatch, {
+        data: {
+          site: {
+            label: "baz",
+            url: "https://foo.bar",
+            customScreenshotURL: null,
+          },
+          index: 7,
+        },
+        meta: { from: "ActivityStream:Content", to: "ActivityStream:Main" },
+        type: at.TOP_SITES_PIN,
+      });
+    });
+    it("should call onClose and dispatch with right args if URL is valid (negative index)", () => {
+      wrapper.setProps({ index: -1 });
+      wrapper.find(".done").simulate("submit");
+      assert.calledOnce(wrapper.instance().props.onClose);
+      assert.calledTwice(wrapper.instance().props.dispatch);
+      assert.calledWith(wrapper.instance().props.dispatch, {
+        data: {
+          site: {
+            label: "baz",
+            url: "https://foo.bar",
+            customScreenshotURL: "http://foo",
+          },
+          index: -1,
+        },
+        meta: { from: "ActivityStream:Content", to: "ActivityStream:Main" },
+        type: at.TOP_SITES_PIN,
+      });
+    });
+    it("should not pass empty string label in dispatch data", () => {
+      wrapper.setState({ label: "" });
+      wrapper.find(".done").simulate("submit");
+      assert.calledWith(wrapper.instance().props.dispatch, {
+        data: {
+          site: { url: "https://foo.bar", customScreenshotURL: "http://foo" },
+          index: 7,
+        },
+        meta: { from: "ActivityStream:Content", to: "ActivityStream:Main" },
+        type: at.TOP_SITES_PIN,
+      });
+    });
+    it("should render the save button if custom screenshot request finished", () => {
+      wrapper.setState({
+        customScreenshotUrl: "foo",
+        screenshotPreview: "custom",
+      });
+      assert.equal(0, wrapper.find(".preview").length);
+      assert.equal(1, wrapper.find(".done").length);
+    });
+    it("should render the save button if custom screenshot url was cleared", () => {
+      wrapper.setState({ customScreenshotUrl: "" });
+      wrapper.setProps({ site: { customScreenshotURL: "foo" } });
+      assert.equal(0, wrapper.find(".preview").length);
+      assert.equal(1, wrapper.find(".done").length);
+    });
+  });
+
+  describe("#previewMode", () => {
+    beforeEach(() => setup({ previewResponse: null }));
+
+    it("should transition from save to preview", () => {
+      wrapper.setProps({
+        site: { url: "https://foo.bar", customScreenshotURL: "baz" },
+        index: 7,
+      });
+
+      assert.equal(
+        wrapper.findWhere(
+          n =>
+            n.length && n.prop("data-l10n-id") === "newtab-topsites-save-button"
+        ).length,
+        1
+      );
+
+      wrapper.setState({ customScreenshotUrl: "foo" });
+
+      assert.equal(
+        wrapper.findWhere(
+          n =>
+            n.length &&
+            n.prop("data-l10n-id") === "newtab-topsites-preview-button"
+        ).length,
+        1
+      );
+    });
+
+    it("should transition from add to preview", () => {
+      assert.equal(
+        wrapper.findWhere(
+          n =>
+            n.length && n.prop("data-l10n-id") === "newtab-topsites-add-button"
+        ).length,
+        1
+      );
+
+      wrapper.setState({ customScreenshotUrl: "foo" });
+
+      assert.equal(
+        wrapper.findWhere(
+          n =>
+            n.length &&
+            n.prop("data-l10n-id") === "newtab-topsites-preview-button"
+        ).length,
+        1
+      );
+    });
+  });
+
+  describe("#validateUrl", () => {
+    it("should properly validate URLs", () => {
+      setup();
+      assert.ok(wrapper.instance().validateUrl("mozilla.org"));
+      assert.ok(wrapper.instance().validateUrl("https://mozilla.org"));
+      assert.ok(wrapper.instance().validateUrl("http://mozilla.org"));
+      assert.ok(
+        wrapper
+          .instance()
+          .validateUrl(
+            "https://mozilla.invisionapp.com/d/main/#/projects/prototypes"
+          )
+      );
+      assert.ok(wrapper.instance().validateUrl("httpfoobar"));
+      assert.ok(wrapper.instance().validateUrl("httpsfoo.bar"));
+      assert.isNull(wrapper.instance().validateUrl("mozilla org"));
+      assert.isNull(wrapper.instance().validateUrl(""));
+    });
+  });
+
+  describe("#cleanUrl", () => {
+    it("should properly prepend http:// to URLs when required", () => {
+      setup();
+      assert.equal(
+        "http://mozilla.org",
+        wrapper.instance().cleanUrl("mozilla.org")
+      );
+      assert.equal(
+        "http://https.org",
+        wrapper.instance().cleanUrl("https.org")
+      );
+      assert.equal("http://httpcom", wrapper.instance().cleanUrl("httpcom"));
+      assert.equal(
+        "http://mozilla.org",
+        wrapper.instance().cleanUrl("http://mozilla.org")
+      );
+      assert.equal(
+        "https://firefox.com",
+        wrapper.instance().cleanUrl("https://firefox.com")
+      );
+    });
+  });
+});
+
+describe("<TopSiteList>", () => {
+  const APP = { isForStartupCache: false };
+
+  it("should render a TopSiteList element", () => {
+    const wrapper = shallow(<TopSiteList {...DEFAULT_PROPS} App={{ APP }} />);
+    assert.ok(wrapper.exists());
+  });
+  it("should render a TopSite for each link with the right url", () => {
+    const rows = [{ url: "https://foo.com" }, { url: "https://bar.com" }];
+    const wrapper = shallow(
+      <TopSiteList {...DEFAULT_PROPS} TopSites={{ rows }} App={{ APP }} />
+    );
+    const links = wrapper.find(TopSite);
+    assert.lengthOf(links, 2);
+    rows.forEach((row, i) =>
+      assert.equal(links.get(i).props.link.url, row.url)
+    );
+  });
+  it("should slice the TopSite rows to the TopSitesRows pref", () => {
+    const rows = [];
+    for (
+      let i = 0;
+      i < TOP_SITES_DEFAULT_ROWS * TOP_SITES_MAX_SITES_PER_ROW + 3;
+      i++
+    ) {
+      rows.push({ url: `https://foo${i}.com` });
+    }
+    const wrapper = shallow(
+      <TopSiteList
+        {...DEFAULT_PROPS}
+        TopSites={{ rows }}
+        TopSitesRows={TOP_SITES_DEFAULT_ROWS}
+        App={{ APP }}
+      />
+    );
+    const links = wrapper.find(TopSite);
+    assert.lengthOf(
+      links,
+      TOP_SITES_DEFAULT_ROWS * TOP_SITES_MAX_SITES_PER_ROW
+    );
+  });
+  it("should fill with placeholders if TopSites rows is less than TopSitesRows", () => {
+    const rows = [{ url: "https://foo.com" }, { url: "https://bar.com" }];
+    const wrapper = shallow(
+      <TopSiteList
+        {...DEFAULT_PROPS}
+        TopSites={{ rows }}
+        TopSitesRows={1}
+        App={{ APP }}
+      />
+    );
+    assert.lengthOf(wrapper.find(TopSite), 2, "topSites");
+    assert.lengthOf(
+      wrapper.find(TopSitePlaceholder),
+      TOP_SITES_MAX_SITES_PER_ROW - 2,
+      "placeholders"
+    );
+  });
+  it("should fill sponsored top sites with placeholders while rendering for startup cache", () => {
+    const rows = [
+      { url: "https://sponsored01.com", sponsored_position: 1 },
+      { url: "https://sponsored02.com", sponsored_position: 2 },
+      { url: "https://sponsored03.com", type: "SPOC" },
+      { url: "https://foo.com" },
+      { url: "https://bar.com" },
+    ];
+    const wrapper = shallow(
+      <TopSiteList
+        {...DEFAULT_PROPS}
+        TopSites={{ rows }}
+        TopSitesRows={1}
+        App={{ isForStartupCache: true }}
+      />
+    );
+    assert.lengthOf(wrapper.find(TopSite), 2, "topSites");
+    assert.lengthOf(
+      wrapper.find(TopSitePlaceholder),
+      TOP_SITES_MAX_SITES_PER_ROW - 2,
+      "placeholders"
+    );
+  });
+  it("should fill any holes in TopSites with placeholders", () => {
+    const rows = [{ url: "https://foo.com" }];
+    rows[3] = { url: "https://bar.com" };
+    const wrapper = shallow(
+      <TopSiteList
+        {...DEFAULT_PROPS}
+        TopSites={{ rows }}
+        TopSitesRows={1}
+        App={{ APP }}
+      />
+    );
+    assert.lengthOf(wrapper.find(TopSite), 2, "topSites");
+    assert.lengthOf(
+      wrapper.find(TopSitePlaceholder),
+      TOP_SITES_MAX_SITES_PER_ROW - 2,
+      "placeholders"
+    );
+  });
+  it("should update state onDragStart and clear it onDragEnd", () => {
+    const wrapper = shallow(<TopSiteList {...DEFAULT_PROPS} App={{ APP }} />);
+    const instance = wrapper.instance();
+    const index = 7;
+    const link = { url: "https://foo.com" };
+    const title = "foo";
+    instance.onDragEvent({ type: "dragstart" }, index, link, title);
+    assert.equal(instance.state.draggedIndex, index);
+    assert.equal(instance.state.draggedSite, link);
+    assert.equal(instance.state.draggedTitle, title);
+    instance.onDragEvent({ type: "dragend" });
+    assert.deepEqual(instance.state, TopSiteList.DEFAULT_STATE);
+  });
+  it("should clear state when new props arrive after a drop", () => {
+    const site1 = { url: "https://foo.com" };
+    const site2 = { url: "https://bar.com" };
+    const rows = [site1, site2];
+    const wrapper = shallow(
+      <TopSiteList {...DEFAULT_PROPS} TopSites={{ rows }} App={{ APP }} />
+    );
+    const instance = wrapper.instance();
+    instance.setState({
+      draggedIndex: 1,
+      draggedSite: site2,
+      draggedTitle: "bar",
+      topSitesPreview: [],
+    });
+    wrapper.setProps({ TopSites: { rows: [site2, site1] } });
+    assert.deepEqual(instance.state, TopSiteList.DEFAULT_STATE);
+  });
+  it("should dispatch events on drop", () => {
+    const dispatch = sinon.spy();
+    const wrapper = shallow(
+      <TopSiteList {...DEFAULT_PROPS} dispatch={dispatch} App={{ APP }} />
+    );
+    const instance = wrapper.instance();
+    const index = 7;
+    const link = { url: "https://foo.com", customScreenshotURL: "foo" };
+    const title = "foo";
+    instance.onDragEvent({ type: "dragstart" }, index, link, title);
+    dispatch.resetHistory();
+    instance.onDragEvent({ type: "drop" }, 3);
+    assert.calledTwice(dispatch);
+    assert.calledWith(dispatch, {
+      data: {
+        draggedFromIndex: 7,
+        index: 3,
+        site: {
+          label: "foo",
+          url: "https://foo.com",
+          customScreenshotURL: "foo",
+        },
+      },
+      meta: { from: "ActivityStream:Content", to: "ActivityStream:Main" },
+      type: "TOP_SITES_INSERT",
+    });
+    assert.calledWith(dispatch, {
+      data: { action_position: 3, event: "DROP", source: "TOP_SITES" },
+      meta: { from: "ActivityStream:Content", to: "ActivityStream:Main" },
+      type: "TELEMETRY_USER_EVENT",
+    });
+  });
+  it("should make a topSitesPreview onDragEnter", () => {
+    const wrapper = shallow(<TopSiteList {...DEFAULT_PROPS} App={{ APP }} />);
+    const instance = wrapper.instance();
+    const site = { url: "https://foo.com" };
+    instance.setState({
+      draggedIndex: 4,
+      draggedSite: site,
+      draggedTitle: "foo",
+    });
+    const draggedSite = Object.assign({}, site, {
+      isPinned: true,
+      isDragged: true,
+    });
+    instance.onDragEvent({ type: "dragenter" }, 2);
+    assert.ok(instance.state.topSitesPreview);
+    assert.deepEqual(instance.state.topSitesPreview[2], draggedSite);
+  });
+  it("should _makeTopSitesPreview correctly", () => {
+    const site1 = { url: "https://foo.com" };
+    const site2 = { url: "https://bar.com" };
+    const site3 = { url: "https://baz.com" };
+    const rows = [site1, site2, site3];
+    let wrapper = shallow(
+      <TopSiteList
+        {...DEFAULT_PROPS}
+        TopSites={{ rows }}
+        TopSitesRows={1}
+        App={{ APP }}
+      />
+    );
+    let instance = wrapper.instance();
+    instance.setState({
+      draggedIndex: 0,
+      draggedSite: site1,
+      draggedTitle: "foo",
+    });
+    let draggedSite = Object.assign({}, site1, {
+      isPinned: true,
+      isDragged: true,
+    });
+    assert.deepEqual(instance._makeTopSitesPreview(1), [
+      site2,
+      draggedSite,
+      site3,
+      null,
+      null,
+      null,
+      null,
+      null,
+    ]);
+    assert.deepEqual(instance._makeTopSitesPreview(2), [
+      site2,
+      site3,
+      draggedSite,
+      null,
+      null,
+      null,
+      null,
+      null,
+    ]);
+    assert.deepEqual(instance._makeTopSitesPreview(3), [
+      site2,
+      site3,
+      null,
+      draggedSite,
+      null,
+      null,
+      null,
+      null,
+    ]);
+    site2.isPinned = true;
+    assert.deepEqual(instance._makeTopSitesPreview(1), [
+      site2,
+      draggedSite,
+      site3,
+      null,
+      null,
+      null,
+      null,
+      null,
+    ]);
+    assert.deepEqual(instance._makeTopSitesPreview(2), [
+      site3,
+      site2,
+      draggedSite,
+      null,
+      null,
+      null,
+      null,
+      null,
+    ]);
+    site3.isPinned = true;
+    assert.deepEqual(instance._makeTopSitesPreview(1), [
+      site2,
+      draggedSite,
+      site3,
+      null,
+      null,
+      null,
+      null,
+      null,
+    ]);
+    assert.deepEqual(instance._makeTopSitesPreview(2), [
+      site2,
+      site3,
+      draggedSite,
+      null,
+      null,
+      null,
+      null,
+      null,
+    ]);
+    site2.isPinned = false;
+    assert.deepEqual(instance._makeTopSitesPreview(1), [
+      site2,
+      draggedSite,
+      site3,
+      null,
+      null,
+      null,
+      null,
+      null,
+    ]);
+    assert.deepEqual(instance._makeTopSitesPreview(2), [
+      site2,
+      site3,
+      draggedSite,
+      null,
+      null,
+      null,
+      null,
+      null,
+    ]);
+    site3.isPinned = false;
+    instance.setState({
+      draggedIndex: 1,
+      draggedSite: site2,
+      draggedTitle: "bar",
+    });
+    draggedSite = Object.assign({}, site2, { isPinned: true, isDragged: true });
+    assert.deepEqual(instance._makeTopSitesPreview(0), [
+      draggedSite,
+      site1,
+      site3,
+      null,
+      null,
+      null,
+      null,
+      null,
+    ]);
+    assert.deepEqual(instance._makeTopSitesPreview(2), [
+      site1,
+      site3,
+      draggedSite,
+      null,
+      null,
+      null,
+      null,
+      null,
+    ]);
+    site2.type = "SPOC";
+    instance.setState({
+      draggedIndex: 2,
+      draggedSite: site3,
+      draggedTitle: "baz",
+    });
+    draggedSite = Object.assign({}, site3, { isPinned: true, isDragged: true });
+    assert.deepEqual(instance._makeTopSitesPreview(0), [
+      draggedSite,
+      site2,
+      site1,
+      null,
+      null,
+      null,
+      null,
+      null,
+    ]);
+    site2.type = "";
+    site2.sponsored_position = 2;
+    instance.setState({
+      draggedIndex: 2,
+      draggedSite: site3,
+      draggedTitle: "baz",
+    });
+    draggedSite = Object.assign({}, site3, { isPinned: true, isDragged: true });
+    assert.deepEqual(instance._makeTopSitesPreview(0), [
+      draggedSite,
+      site2,
+      site1,
+      null,
+      null,
+      null,
+      null,
+      null,
+    ]);
+  });
+  it("should add a className hide-for-narrow to sites after 6/row", () => {
+    const rows = [];
+    for (let i = 0; i < TOP_SITES_MAX_SITES_PER_ROW; i++) {
+      rows.push({ url: `https://foo${i}.com` });
+    }
+    const wrapper = mount(
+      <TopSiteList
+        {...DEFAULT_PROPS}
+        TopSites={{ rows }}
+        TopSitesRows={1}
+        App={{ APP }}
+      />
+    );
+    assert.lengthOf(wrapper.find("li.hide-for-narrow"), 2);
+  });
+});
+
+describe("TopSitePlaceholder", () => {
+  it("should dispatch a TOP_SITES_EDIT action when edit-button is clicked", () => {
+    const dispatch = sinon.spy();
+    const wrapper = shallow(
+      <TopSitePlaceholder dispatch={dispatch} index={7} />
+    );
+
+    wrapper.find(".edit-button").first().simulate("click");
+
+    assert.calledOnce(dispatch);
+    assert.calledWithExactly(dispatch, {
+      type: at.TOP_SITES_EDIT,
+      data: { index: 7 },
+    });
+  });
+});
+
+describe("#TopSiteFormInput", () => {
+  let wrapper;
+  let onChangeStub;
+
+  describe("no errors", () => {
+    beforeEach(() => {
+      onChangeStub = sinon.stub();
+
+      wrapper = mount(
+        <TopSiteFormInput
+          titleId="newtab-topsites-title-label"
+          placeholderId="newtab-topsites-title-input"
+          errorMessageId="newtab-topsites-url-validation"
+          onChange={onChangeStub}
+          value="foo"
+        />
+      );
+    });
+
+    it("should render the provided title", () => {
+      const title = wrapper.find("span");
+      assert.propertyVal(
+        title.props(),
+        "data-l10n-id",
+        "newtab-topsites-title-label"
+      );
+    });
+
+    it("should render the provided value", () => {
+      const input = wrapper.find("input");
+
+      assert.equal(input.getDOMNode().value, "foo");
+    });
+
+    it("should render the clear button if cb is provided", () => {
+      assert.equal(wrapper.find(".icon-clear-input").length, 0);
+
+      wrapper.setProps({ onClear: sinon.stub() });
+
+      assert.equal(wrapper.find(".icon-clear-input").length, 1);
+    });
+
+    it("should show the loading indicator", () => {
+      assert.equal(wrapper.find(".loading-container").length, 0);
+
+      wrapper.setProps({ loading: true });
+
+      assert.equal(wrapper.find(".loading-container").length, 1);
+    });
+    it("should disable the input when loading indicator is present", () => {
+      assert.isFalse(wrapper.find("input").getDOMNode().disabled);
+
+      wrapper.setProps({ loading: true });
+
+      assert.isTrue(wrapper.find("input").getDOMNode().disabled);
+    });
+  });
+
+  describe("with error", () => {
+    beforeEach(() => {
+      onChangeStub = sinon.stub();
+
+      wrapper = mount(
+        <TopSiteFormInput
+          titleId="newtab-topsites-title-label"
+          placeholderId="newtab-topsites-title-input"
+          onChange={onChangeStub}
+          validationError={true}
+          errorMessageId="newtab-topsites-url-validation"
+          value="foo"
+        />
+      );
+    });
+
+    it("should render the error message", () => {
+      assert.equal(
+        wrapper.findWhere(
+          n => n.prop("data-l10n-id") === "newtab-topsites-url-validation"
+        ).length,
+        1
+      );
+    });
+
+    it("should reset the error state on value change", () => {
+      wrapper.find("input").simulate("change", { target: { value: "bar" } });
+
+      assert.isFalse(wrapper.state().validationError);
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/TopSites/SearchShortcutsForm.test.jsx b/browser/components/newtab/test/unit/content-src/components/TopSites/SearchShortcutsForm.test.jsx
new file mode 100644
index 0000000000..22c4e8192a
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/TopSites/SearchShortcutsForm.test.jsx
@@ -0,0 +1,56 @@
+import {
+  SearchShortcutsForm,
+  SelectableSearchShortcut,
+} from "content-src/components/TopSites/SearchShortcutsForm";
+import React from "react";
+import { shallow } from "enzyme";
+
+describe("<SearchShortcutsForm>", () => {
+  let wrapper;
+  let sandbox;
+  let dispatchStub;
+
+  beforeEach(() => {
+    sandbox = sinon.createSandbox();
+    dispatchStub = sandbox.stub();
+    const defaultProps = { rows: [], searchShortcuts: [] };
+    wrapper = shallow(
+      <SearchShortcutsForm TopSites={defaultProps} dispatch={dispatchStub} />
+    );
+  });
+
+  afterEach(() => {
+    sandbox.restore();
+  });
+
+  it("should render", () => {
+    assert.ok(wrapper.exists());
+    assert.ok(wrapper.find(".topsite-form").exists());
+  });
+
+  it("should render SelectableSearchShortcut components", () => {
+    wrapper.setState({ shortcuts: [{}, {}] });
+
+    assert.lengthOf(
+      wrapper.find(".search-shortcuts-container div").children(),
+      2
+    );
+    assert.equal(
+      wrapper.find(".search-shortcuts-container div").children().at(0).type(),
+      SelectableSearchShortcut
+    );
+  });
+
+  it("should render SelectableSearchShortcut components", () => {
+    const onCloseStub = sandbox.stub();
+    const fakeEvent = { preventDefault: sandbox.stub() };
+    wrapper.setState({ shortcuts: [{}, {}] });
+    wrapper.setProps({ onClose: onCloseStub });
+
+    wrapper.find(".done").simulate("click", fakeEvent);
+
+    assert.calledOnce(dispatchStub);
+    assert.calledOnce(fakeEvent.preventDefault);
+    assert.calledOnce(onCloseStub);
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/TopSites/TopSiteImpressionWrapper.test.jsx b/browser/components/newtab/test/unit/content-src/components/TopSites/TopSiteImpressionWrapper.test.jsx
new file mode 100644
index 0000000000..3f7e725de0
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/TopSites/TopSiteImpressionWrapper.test.jsx
@@ -0,0 +1,148 @@
+import {
+  TopSiteImpressionWrapper,
+  INTERSECTION_RATIO,
+} from "content-src/components/TopSites/TopSiteImpressionWrapper";
+import { actionTypes as at } from "common/Actions.sys.mjs";
+import React from "react";
+import { shallow } from "enzyme";
+
+describe("<TopSiteImpressionWrapper>", () => {
+  const FullIntersectEntries = [
+    { isIntersecting: true, intersectionRatio: INTERSECTION_RATIO },
+  ];
+  const ZeroIntersectEntries = [
+    { isIntersecting: false, intersectionRatio: 0 },
+  ];
+  const PartialIntersectEntries = [
+    { isIntersecting: true, intersectionRatio: INTERSECTION_RATIO / 2 },
+  ];
+
+  // Build IntersectionObserver class with the arg `entries` for the intersect callback.
+  function buildIntersectionObserver(entries) {
+    return class {
+      constructor(callback) {
+        this.callback = callback;
+      }
+
+      observe() {
+        this.callback(entries);
+      }
+
+      unobserve() {}
+    };
+  }
+
+  const DEFAULT_PROPS = {
+    actionType: at.TOP_SITES_SPONSORED_IMPRESSION_STATS,
+    tile: {
+      tile_id: 1,
+      position: 1,
+      reporting_url: "https://test.reporting.com",
+      advertiser: "test_advertiser",
+    },
+    IntersectionObserver: buildIntersectionObserver(FullIntersectEntries),
+    document: {
+      visibilityState: "visible",
+      addEventListener: sinon.stub(),
+      removeEventListener: sinon.stub(),
+    },
+  };
+
+  const InnerEl = () => <div>Inner Element</div>;
+
+  function renderTopSiteImpressionWrapper(props = {}) {
+    return shallow(
+      <TopSiteImpressionWrapper {...DEFAULT_PROPS} {...props}>
+        <InnerEl />
+      </TopSiteImpressionWrapper>
+    );
+  }
+
+  it("should render props.children", () => {
+    const wrapper = renderTopSiteImpressionWrapper();
+    assert.ok(wrapper.contains(<InnerEl />));
+  });
+  it("should not send impression when the wrapped item is visbible but below the ratio", () => {
+    const dispatch = sinon.spy();
+    const props = {
+      dispatch,
+      IntersectionObserver: buildIntersectionObserver(PartialIntersectEntries),
+    };
+    renderTopSiteImpressionWrapper(props);
+
+    assert.notCalled(dispatch);
+  });
+  it("should send an impression when the page is visible and the wrapped item meets the visibility ratio", () => {
+    const dispatch = sinon.spy();
+    const props = {
+      dispatch,
+      IntersectionObserver: buildIntersectionObserver(FullIntersectEntries),
+    };
+    renderTopSiteImpressionWrapper(props);
+
+    assert.calledOnce(dispatch);
+
+    let [action] = dispatch.firstCall.args;
+    assert.equal(action.type, at.TOP_SITES_SPONSORED_IMPRESSION_STATS);
+    assert.deepEqual(action.data, {
+      type: "impression",
+      ...DEFAULT_PROPS.tile,
+    });
+  });
+  it("should send an impression when the wrapped item transiting from invisible to visible", () => {
+    const dispatch = sinon.spy();
+    const props = {
+      dispatch,
+      IntersectionObserver: buildIntersectionObserver(ZeroIntersectEntries),
+    };
+    const wrapper = renderTopSiteImpressionWrapper(props);
+
+    assert.notCalled(dispatch);
+
+    dispatch.resetHistory();
+    wrapper.instance().impressionObserver.callback(FullIntersectEntries);
+
+    // For the impression
+    assert.calledOnce(dispatch);
+
+    const [action] = dispatch.firstCall.args;
+    assert.equal(action.type, at.TOP_SITES_SPONSORED_IMPRESSION_STATS);
+    assert.deepEqual(action.data, {
+      type: "impression",
+      ...DEFAULT_PROPS.tile,
+    });
+  });
+  it("should remove visibility change listener when the wrapper is removed", () => {
+    const props = {
+      dispatch: sinon.spy(),
+      document: {
+        visibilityState: "hidden",
+        addEventListener: sinon.spy(),
+        removeEventListener: sinon.spy(),
+      },
+      IntersectionObserver,
+    };
+
+    const wrapper = renderTopSiteImpressionWrapper(props);
+    assert.calledWith(props.document.addEventListener, "visibilitychange");
+    const [, listener] = props.document.addEventListener.firstCall.args;
+
+    wrapper.unmount();
+    assert.calledWith(
+      props.document.removeEventListener,
+      "visibilitychange",
+      listener
+    );
+  });
+  it("should unobserve the intersection observer when the wrapper is removed", () => {
+    const IntersectionObserver =
+      buildIntersectionObserver(ZeroIntersectEntries);
+    const spy = sinon.spy(IntersectionObserver.prototype, "unobserve");
+    const props = { dispatch: sinon.spy(), IntersectionObserver };
+
+    const wrapper = renderTopSiteImpressionWrapper(props);
+    wrapper.unmount();
+
+    assert.calledOnce(spy);
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/components/Topics.test.jsx b/browser/components/newtab/test/unit/content-src/components/Topics.test.jsx
new file mode 100644
index 0000000000..91d15c5d4e
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/components/Topics.test.jsx
@@ -0,0 +1,22 @@
+import { Topic, Topics } from "content-src/components/Topics/Topics";
+import React from "react";
+import { shallow } from "enzyme";
+
+describe("<Topics>", () => {
+  it("should render a Topics element", () => {
+    const wrapper = shallow(<Topics topics={[]} />);
+    assert.ok(wrapper.exists());
+  });
+  it("should render a Topic element for each topic with the right url", () => {
+    const data = [
+      { name: "topic1", url: "https://topic1.com" },
+      { name: "topic2", url: "https://topic2.com" },
+    ];
+
+    const wrapper = shallow(<Topics topics={data} />);
+
+    const topics = wrapper.find(Topic);
+    assert.lengthOf(topics, 2);
+    topics.forEach((topic, i) => assert.equal(topic.props().url, data[i].url));
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/lib/detect-user-session-start.test.js b/browser/components/newtab/test/unit/content-src/lib/detect-user-session-start.test.js
new file mode 100644
index 0000000000..5a7fad7cc0
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/lib/detect-user-session-start.test.js
@@ -0,0 +1,120 @@
+import {
+  actionCreators as ac,
+  actionTypes as at,
+} from "common/Actions.sys.mjs";
+import { DetectUserSessionStart } from "content-src/lib/detect-user-session-start";
+
+describe("detectUserSessionStart", () => {
+  let store;
+  class PerfService {
+    getMostRecentAbsMarkStartByName() {
+      return 1234;
+    }
+    mark() {}
+  }
+
+  beforeEach(() => {
+    store = { dispatch: () => {} };
+  });
+  describe("#sendEventOrAddListener", () => {
+    it("should call ._sendEvent immediately if the document is visible", () => {
+      const mockDocument = { visibilityState: "visible" };
+      const instance = new DetectUserSessionStart(store, {
+        document: mockDocument,
+      });
+      sinon.stub(instance, "_sendEvent");
+
+      instance.sendEventOrAddListener();
+
+      assert.calledOnce(instance._sendEvent);
+    });
+    it("should add an event listener on visibility changes the document is not visible", () => {
+      const mockDocument = {
+        visibilityState: "hidden",
+        addEventListener: sinon.spy(),
+      };
+      const instance = new DetectUserSessionStart(store, {
+        document: mockDocument,
+      });
+      sinon.stub(instance, "_sendEvent");
+
+      instance.sendEventOrAddListener();
+
+      assert.notCalled(instance._sendEvent);
+      assert.calledWith(
+        mockDocument.addEventListener,
+        "visibilitychange",
+        instance._onVisibilityChange
+      );
+    });
+  });
+  describe("#_sendEvent", () => {
+    it("should dispatch an action with the SAVE_SESSION_PERF_DATA", () => {
+      const dispatch = sinon.spy(store, "dispatch");
+      const instance = new DetectUserSessionStart(store);
+
+      instance._sendEvent();
+
+      assert.calledWith(
+        dispatch,
+        ac.AlsoToMain({
+          type: at.SAVE_SESSION_PERF_DATA,
+          data: { visibility_event_rcvd_ts: sinon.match.number },
+        })
+      );
+    });
+
+    it("shouldn't send a message if getMostRecentAbsMarkStartByName throws", () => {
+      let perfService = new PerfService();
+      sinon.stub(perfService, "getMostRecentAbsMarkStartByName").throws();
+      const dispatch = sinon.spy(store, "dispatch");
+      const instance = new DetectUserSessionStart(store, { perfService });
+
+      instance._sendEvent();
+
+      assert.notCalled(dispatch);
+    });
+
+    it('should call perfService.mark("visibility_event_rcvd_ts")', () => {
+      let perfService = new PerfService();
+      sinon.stub(perfService, "mark");
+      const instance = new DetectUserSessionStart(store, { perfService });
+
+      instance._sendEvent();
+
+      assert.calledWith(perfService.mark, "visibility_event_rcvd_ts");
+    });
+  });
+
+  describe("_onVisibilityChange", () => {
+    it("should not send an event if visiblity is not visible", () => {
+      const instance = new DetectUserSessionStart(store, {
+        document: { visibilityState: "hidden" },
+      });
+      sinon.stub(instance, "_sendEvent");
+
+      instance._onVisibilityChange();
+
+      assert.notCalled(instance._sendEvent);
+    });
+    it("should send an event and remove the event listener if visibility is visible", () => {
+      const mockDocument = {
+        visibilityState: "visible",
+        removeEventListener: sinon.spy(),
+      };
+      const instance = new DetectUserSessionStart(store, {
+        document: mockDocument,
+      });
+      sinon.stub(instance, "_sendEvent");
+
+      instance._onVisibilityChange();
+
+      assert.calledOnce(instance._sendEvent);
+      assert.calledWith(
+        mockDocument.removeEventListener,
+        "visibilitychange",
+        instance._onVisibilityChange
+      );
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/lib/init-store.test.js b/browser/components/newtab/test/unit/content-src/lib/init-store.test.js
new file mode 100644
index 0000000000..0dd510ef1a
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/lib/init-store.test.js
@@ -0,0 +1,155 @@
+import {
+  actionCreators as ac,
+  actionTypes as at,
+} from "common/Actions.sys.mjs";
+import { addNumberReducer, GlobalOverrider } from "test/unit/utils";
+import {
+  INCOMING_MESSAGE_NAME,
+  initStore,
+  MERGE_STORE_ACTION,
+  OUTGOING_MESSAGE_NAME,
+  rehydrationMiddleware,
+} from "content-src/lib/init-store";
+
+describe("initStore", () => {
+  let globals;
+  let store;
+  beforeEach(() => {
+    globals = new GlobalOverrider();
+    globals.set("RPMSendAsyncMessage", globals.sandbox.spy());
+    globals.set("RPMAddMessageListener", globals.sandbox.spy());
+    store = initStore({ number: addNumberReducer });
+  });
+  afterEach(() => globals.restore());
+  it("should create a store with the provided reducers", () => {
+    assert.ok(store);
+    assert.property(store.getState(), "number");
+  });
+  it("should add a listener that dispatches actions", () => {
+    assert.calledWith(global.RPMAddMessageListener, INCOMING_MESSAGE_NAME);
+    const [, listener] = global.RPMAddMessageListener.firstCall.args;
+    globals.sandbox.spy(store, "dispatch");
+    const message = { name: INCOMING_MESSAGE_NAME, data: { type: "FOO" } };
+
+    listener(message);
+
+    assert.calledWith(store.dispatch, message.data);
+  });
+  it("should not throw if RPMAddMessageListener is not defined", () => {
+    // Note: this is being set/restored by GlobalOverrider
+    delete global.RPMAddMessageListener;
+
+    assert.doesNotThrow(() => initStore({ number: addNumberReducer }));
+  });
+  it("should log errors from failed messages", () => {
+    const [, callback] = global.RPMAddMessageListener.firstCall.args;
+    globals.sandbox.stub(global.console, "error");
+    globals.sandbox.stub(store, "dispatch").throws(Error("failed"));
+
+    const message = {
+      name: INCOMING_MESSAGE_NAME,
+      data: { type: MERGE_STORE_ACTION },
+    };
+    callback(message);
+
+    assert.calledOnce(global.console.error);
+  });
+  it("should replace the state if a MERGE_STORE_ACTION is dispatched", () => {
+    store.dispatch({ type: MERGE_STORE_ACTION, data: { number: 42 } });
+    assert.deepEqual(store.getState(), { number: 42 });
+  });
+  it("should call .send and update the local store if an AlsoToMain action is dispatched", () => {
+    const subscriber = sinon.spy();
+    const action = ac.AlsoToMain({ type: "FOO" });
+
+    store.subscribe(subscriber);
+    store.dispatch(action);
+
+    assert.calledWith(
+      global.RPMSendAsyncMessage,
+      OUTGOING_MESSAGE_NAME,
+      action
+    );
+    assert.calledOnce(subscriber);
+  });
+  it("should call .send but not update the local store if an OnlyToMain action is dispatched", () => {
+    const subscriber = sinon.spy();
+    const action = ac.OnlyToMain({ type: "FOO" });
+
+    store.subscribe(subscriber);
+    store.dispatch(action);
+
+    assert.calledWith(
+      global.RPMSendAsyncMessage,
+      OUTGOING_MESSAGE_NAME,
+      action
+    );
+    assert.notCalled(subscriber);
+  });
+  it("should not send out other types of actions", () => {
+    store.dispatch({ type: "FOO" });
+    assert.notCalled(global.RPMSendAsyncMessage);
+  });
+  describe("rehydrationMiddleware", () => {
+    it("should allow NEW_TAB_STATE_REQUEST to go through", () => {
+      const action = ac.AlsoToMain({ type: at.NEW_TAB_STATE_REQUEST });
+      const next = sinon.spy();
+      rehydrationMiddleware(store)(next)(action);
+      assert.calledWith(next, action);
+    });
+    it("should dispatch an additional NEW_TAB_STATE_REQUEST if INIT was received after a request", () => {
+      const requestAction = ac.AlsoToMain({ type: at.NEW_TAB_STATE_REQUEST });
+      const next = sinon.spy();
+      const dispatch = rehydrationMiddleware(store)(next);
+
+      dispatch(requestAction);
+      next.resetHistory();
+      dispatch({ type: at.INIT });
+
+      assert.calledWith(next, requestAction);
+    });
+    it("should allow MERGE_STORE_ACTION to go through", () => {
+      const action = { type: MERGE_STORE_ACTION };
+      const next = sinon.spy();
+      rehydrationMiddleware(store)(next)(action);
+      assert.calledWith(next, action);
+    });
+    it("should not allow actions from main to go through before MERGE_STORE_ACTION was received", () => {
+      const next = sinon.spy();
+      const dispatch = rehydrationMiddleware(store)(next);
+
+      dispatch(ac.BroadcastToContent({ type: "FOO" }));
+      dispatch(ac.AlsoToOneContent({ type: "FOO" }, 123));
+
+      assert.notCalled(next);
+    });
+    it("should allow all local actions to go through", () => {
+      const action = { type: "FOO" };
+      const next = sinon.spy();
+      rehydrationMiddleware(store)(next)(action);
+      assert.calledWith(next, action);
+    });
+    it("should allow actions from main to go through after MERGE_STORE_ACTION has been received", () => {
+      const next = sinon.spy();
+      const dispatch = rehydrationMiddleware(store)(next);
+
+      dispatch({ type: MERGE_STORE_ACTION });
+      next.resetHistory();
+
+      const action = ac.AlsoToOneContent({ type: "FOO" }, 123);
+      dispatch(action);
+      assert.calledWith(next, action);
+    });
+    it("should not let startup actions go through for the preloaded about:home document", () => {
+      globals.set("__FROM_STARTUP_CACHE__", true);
+      const next = sinon.spy();
+      const dispatch = rehydrationMiddleware(store)(next);
+      const action = ac.BroadcastToContent(
+        { type: "FOO", meta: { isStartup: true } },
+        123
+      );
+      dispatch(action);
+      assert.notCalled(next);
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/lib/perf-service.test.js b/browser/components/newtab/test/unit/content-src/lib/perf-service.test.js
new file mode 100644
index 0000000000..9cabfb5029
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/lib/perf-service.test.js
@@ -0,0 +1,89 @@
+/* globals assert, beforeEach, describe, it */
+import { _PerfService } from "content-src/lib/perf-service";
+import { FakePerformance } from "test/unit/utils.js";
+
+let perfService;
+
+describe("_PerfService", () => {
+  let sandbox;
+  let fakePerfObj;
+
+  beforeEach(() => {
+    sandbox = sinon.createSandbox();
+    fakePerfObj = new FakePerformance();
+    perfService = new _PerfService({ performanceObj: fakePerfObj });
+  });
+
+  afterEach(() => {
+    sandbox.restore();
+  });
+
+  describe("#absNow", () => {
+    it("should return a number > the time origin", () => {
+      const absNow = perfService.absNow();
+
+      assert.isAbove(absNow, perfService.timeOrigin);
+    });
+  });
+  describe("#getEntriesByName", () => {
+    it("should call getEntriesByName on the appropriate Window.performance", () => {
+      sandbox.spy(fakePerfObj, "getEntriesByName");
+
+      perfService.getEntriesByName("monkey", "mark");
+
+      assert.calledOnce(fakePerfObj.getEntriesByName);
+      assert.calledWithExactly(fakePerfObj.getEntriesByName, "monkey", "mark");
+    });
+
+    it("should return entries with the given name", () => {
+      sandbox.spy(fakePerfObj, "getEntriesByName");
+      perfService.mark("monkey");
+      perfService.mark("dog");
+
+      let marks = perfService.getEntriesByName("monkey", "mark");
+
+      assert.isArray(marks);
+      assert.lengthOf(marks, 1);
+      assert.propertyVal(marks[0], "name", "monkey");
+    });
+  });
+
+  describe("#getMostRecentAbsMarkStartByName", () => {
+    it("should throw an error if there is no mark with the given name", () => {
+      function bogusGet() {
+        perfService.getMostRecentAbsMarkStartByName("rheeeet");
+      }
+
+      assert.throws(bogusGet, Error, /No marks with the name/);
+    });
+
+    it("should return the Number from the most recent mark with the given name + the time origin", () => {
+      perfService.mark("dog");
+      perfService.mark("dog");
+
+      let absMarkStart = perfService.getMostRecentAbsMarkStartByName("dog");
+
+      // 2 because we want the result of the 2nd call to mark, and an instance
+      // of FakePerformance just returns the number of time mark has been
+      // called.
+      assert.equal(absMarkStart - perfService.timeOrigin, 2);
+    });
+  });
+
+  describe("#mark", () => {
+    it("should call the wrapped version of mark", () => {
+      sandbox.spy(fakePerfObj, "mark");
+
+      perfService.mark("monkey");
+
+      assert.calledOnce(fakePerfObj.mark);
+      assert.calledWithExactly(fakePerfObj.mark, "monkey");
+    });
+  });
+
+  describe("#timeOrigin", () => {
+    it("should get the origin of the wrapped performance object", () => {
+      assert.equal(perfService.timeOrigin, fakePerfObj.timeOrigin);
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/lib/screenshot-utils.test.js b/browser/components/newtab/test/unit/content-src/lib/screenshot-utils.test.js
new file mode 100644
index 0000000000..ef7e7cf5f6
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/lib/screenshot-utils.test.js
@@ -0,0 +1,147 @@
+import { GlobalOverrider } from "test/unit/utils";
+import { ScreenshotUtils } from "content-src/lib/screenshot-utils";
+
+const DEFAULT_BLOB_URL = "blob://test";
+
+describe("ScreenshotUtils", () => {
+  let globals;
+  let url;
+  beforeEach(() => {
+    globals = new GlobalOverrider();
+    url = {
+      createObjectURL: globals.sandbox.stub().returns(DEFAULT_BLOB_URL),
+      revokeObjectURL: globals.sandbox.spy(),
+    };
+    globals.set("URL", url);
+  });
+  afterEach(() => globals.restore());
+  describe("#createLocalImageObject", () => {
+    it("should return null if no remoteImage is supplied", () => {
+      let localImageObject = ScreenshotUtils.createLocalImageObject(null);
+
+      assert.notCalled(url.createObjectURL);
+      assert.equal(localImageObject, null);
+    });
+    it("should create a local image object with the correct properties if remoteImage is a blob", () => {
+      let localImageObject = ScreenshotUtils.createLocalImageObject({
+        path: "/path1",
+        data: new Blob([0]),
+      });
+
+      assert.calledOnce(url.createObjectURL);
+      assert.deepEqual(localImageObject, {
+        path: "/path1",
+        url: DEFAULT_BLOB_URL,
+      });
+    });
+    it("should create a local image object with the correct properties if remoteImage is a normal image", () => {
+      const imageUrl = "https://test-url";
+      let localImageObject = ScreenshotUtils.createLocalImageObject(imageUrl);
+
+      assert.notCalled(url.createObjectURL);
+      assert.deepEqual(localImageObject, { url: imageUrl });
+    });
+  });
+  describe("#maybeRevokeBlobObjectURL", () => {
+    // Note that we should also ensure that all the tests for #isBlob are green.
+    it("should call revokeObjectURL if image is a blob", () => {
+      ScreenshotUtils.maybeRevokeBlobObjectURL({
+        path: "/path1",
+        url: "blob://test",
+      });
+
+      assert.calledOnce(url.revokeObjectURL);
+    });
+    it("should not call revokeObjectURL if image is not a blob", () => {
+      ScreenshotUtils.maybeRevokeBlobObjectURL({ url: "https://test-url" });
+
+      assert.notCalled(url.revokeObjectURL);
+    });
+  });
+  describe("#isRemoteImageLocal", () => {
+    it("should return true if both propsImage and stateImage are not present", () => {
+      assert.isTrue(ScreenshotUtils.isRemoteImageLocal(null, null));
+    });
+    it("should return false if propsImage is present and stateImage is not present", () => {
+      assert.isFalse(ScreenshotUtils.isRemoteImageLocal(null, {}));
+    });
+    it("should return false if propsImage is not present and stateImage is present", () => {
+      assert.isFalse(ScreenshotUtils.isRemoteImageLocal({}, null));
+    });
+    it("should return true if both propsImage and stateImage are equal blobs", () => {
+      const blobPath = "/test-blob-path/test.png";
+      assert.isTrue(
+        ScreenshotUtils.isRemoteImageLocal(
+          { path: blobPath, url: "blob://test" }, // state
+          { path: blobPath, data: new Blob([0]) } // props
+        )
+      );
+    });
+    it("should return false if both propsImage and stateImage are different blobs", () => {
+      assert.isFalse(
+        ScreenshotUtils.isRemoteImageLocal(
+          { path: "/path1", url: "blob://test" }, // state
+          { path: "/path2", data: new Blob([0]) } // props
+        )
+      );
+    });
+    it("should return true if both propsImage and stateImage are equal normal images", () => {
+      assert.isTrue(
+        ScreenshotUtils.isRemoteImageLocal(
+          { url: "test url" }, // state
+          "test url" // props
+        )
+      );
+    });
+    it("should return false if both propsImage and stateImage are different normal images", () => {
+      assert.isFalse(
+        ScreenshotUtils.isRemoteImageLocal(
+          { url: "test url 1" }, // state
+          "test url 2" // props
+        )
+      );
+    });
+    it("should return false if both propsImage and stateImage are different type of images", () => {
+      assert.isFalse(
+        ScreenshotUtils.isRemoteImageLocal(
+          { path: "/path1", url: "blob://test" }, // state
+          "test url 2" // props
+        )
+      );
+      assert.isFalse(
+        ScreenshotUtils.isRemoteImageLocal(
+          { url: "https://test-url" }, // state
+          { path: "/path1", data: new Blob([0]) } // props
+        )
+      );
+    });
+  });
+  describe("#isBlob", () => {
+    let state = {
+      blobImage: { path: "/test", url: "blob://test" },
+      normalImage: { url: "https://test-url" },
+    };
+    let props = {
+      blobImage: { path: "/test", data: new Blob([0]) },
+      normalImage: "https://test-url",
+    };
+    it("should return false if image is null", () => {
+      assert.isFalse(ScreenshotUtils.isBlob(true, null));
+      assert.isFalse(ScreenshotUtils.isBlob(false, null));
+    });
+    it("should return true if image is a blob and type matches", () => {
+      assert.isTrue(ScreenshotUtils.isBlob(true, state.blobImage));
+      assert.isTrue(ScreenshotUtils.isBlob(false, props.blobImage));
+    });
+    it("should return false if image is not a blob and type matches", () => {
+      assert.isFalse(ScreenshotUtils.isBlob(true, state.normalImage));
+      assert.isFalse(ScreenshotUtils.isBlob(false, props.normalImage));
+    });
+    it("should return false if type does not match", () => {
+      assert.isFalse(ScreenshotUtils.isBlob(false, state.blobImage));
+      assert.isFalse(ScreenshotUtils.isBlob(false, state.normalImage));
+      assert.isFalse(ScreenshotUtils.isBlob(true, props.blobImage));
+      assert.isFalse(ScreenshotUtils.isBlob(true, props.normalImage));
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/content-src/lib/selectLayoutRender.test.js b/browser/components/newtab/test/unit/content-src/lib/selectLayoutRender.test.js
new file mode 100644
index 0000000000..233f31b6ca
--- /dev/null
+++ b/browser/components/newtab/test/unit/content-src/lib/selectLayoutRender.test.js
@@ -0,0 +1,576 @@
+import { combineReducers, createStore } from "redux";
+import { actionTypes as at } from "common/Actions.sys.mjs";
+import { GlobalOverrider } from "test/unit/utils";
+import { reducers } from "common/Reducers.sys.mjs";
+import { selectLayoutRender } from "content-src/lib/selectLayoutRender";
+const FAKE_LAYOUT = [
+  {
+    width: 3,
+    components: [
+      { type: "foo", feed: { url: "foo.com" }, properties: { items: 2 } },
+    ],
+  },
+];
+const FAKE_FEEDS = {
+  "foo.com": { data: { recommendations: [{ id: "foo" }, { id: "bar" }] } },
+};
+
+describe("selectLayoutRender", () => {
+  let store;
+  let globals;
+
+  beforeEach(() => {
+    globals = new GlobalOverrider();
+    store = createStore(combineReducers(reducers));
+  });
+
+  afterEach(() => {
+    globals.restore();
+  });
+
+  it("should return an empty array given initial state", () => {
+    const { layoutRender } = selectLayoutRender({
+      state: store.getState().DiscoveryStream,
+      prefs: {},
+      rollCache: [],
+    });
+    assert.deepEqual(layoutRender, []);
+  });
+
+  it("should add .data property from feeds to each compontent in .layout", () => {
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_LAYOUT_UPDATE,
+      data: { layout: FAKE_LAYOUT },
+    });
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_FEED_UPDATE,
+      data: { feed: FAKE_FEEDS["foo.com"], url: "foo.com" },
+    });
+    store.dispatch({ type: at.DISCOVERY_STREAM_FEEDS_UPDATE });
+
+    const { layoutRender } = selectLayoutRender({
+      state: store.getState().DiscoveryStream,
+    });
+
+    assert.lengthOf(layoutRender, 1);
+    assert.propertyVal(layoutRender[0], "width", 3);
+    assert.deepEqual(layoutRender[0].components[0], {
+      type: "foo",
+      feed: { url: "foo.com" },
+      properties: { items: 2 },
+      data: {
+        recommendations: [
+          { id: "foo", pos: 0 },
+          { id: "bar", pos: 1 },
+        ],
+      },
+    });
+  });
+
+  it("should return layout with placeholder data if feed doesn't have data", () => {
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_LAYOUT_UPDATE,
+      data: { layout: FAKE_LAYOUT },
+    });
+    store.dispatch({ type: at.DISCOVERY_STREAM_FEEDS_UPDATE });
+
+    const { layoutRender } = selectLayoutRender({
+      state: store.getState().DiscoveryStream,
+    });
+
+    assert.lengthOf(layoutRender, 1);
+    assert.propertyVal(layoutRender[0], "width", 3);
+    assert.deepEqual(layoutRender[0].components[0].data.recommendations, [
+      { placeholder: true },
+      { placeholder: true },
+    ]);
+  });
+
+  it("should return layout with empty spocs data if feed isn't defined but spocs is", () => {
+    const fakeLayout = [
+      {
+        width: 3,
+        components: [{ type: "foo", spocs: { positions: [{ index: 2 }] } }],
+      },
+    ];
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_LAYOUT_UPDATE,
+      data: { layout: fakeLayout },
+    });
+    store.dispatch({ type: at.DISCOVERY_STREAM_FEEDS_UPDATE });
+
+    const { layoutRender } = selectLayoutRender({
+      state: store.getState().DiscoveryStream,
+    });
+
+    assert.lengthOf(layoutRender, 1);
+    assert.propertyVal(layoutRender[0], "width", 3);
+    assert.deepEqual(layoutRender[0].components[0].data.spocs, []);
+  });
+
+  it("should return layout with spocs data if feed isn't defined but spocs is", () => {
+    const fakeLayout = [
+      {
+        width: 3,
+        components: [{ type: "foo", spocs: { positions: [{ index: 0 }] } }],
+      },
+    ];
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_LAYOUT_UPDATE,
+      data: { layout: fakeLayout },
+    });
+    store.dispatch({ type: at.DISCOVERY_STREAM_FEEDS_UPDATE });
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_SPOCS_UPDATE,
+      data: {
+        lastUpdated: 0,
+        spocs: {
+          spocs: {
+            items: [{ id: 1 }, { id: 2 }, { id: 3 }],
+          },
+        },
+      },
+    });
+
+    const { layoutRender } = selectLayoutRender({
+      state: store.getState().DiscoveryStream,
+    });
+
+    assert.lengthOf(layoutRender, 1);
+    assert.propertyVal(layoutRender[0], "width", 3);
+    assert.deepEqual(layoutRender[0].components[0].data.spocs, [
+      { id: 1, pos: 0 },
+      { id: 2, pos: 1 },
+      { id: 3, pos: 2 },
+    ]);
+  });
+
+  it("should return layout with no spocs data if feed and spocs are unavailable", () => {
+    const fakeLayout = [
+      {
+        width: 3,
+        components: [{ type: "foo", spocs: { positions: [{ index: 0 }] } }],
+      },
+    ];
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_LAYOUT_UPDATE,
+      data: { layout: fakeLayout },
+    });
+    store.dispatch({ type: at.DISCOVERY_STREAM_FEEDS_UPDATE });
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_SPOCS_UPDATE,
+      data: {
+        lastUpdated: 0,
+        spocs: {
+          spocs: {
+            items: [],
+          },
+        },
+      },
+    });
+
+    const { layoutRender } = selectLayoutRender({
+      state: store.getState().DiscoveryStream,
+    });
+
+    assert.lengthOf(layoutRender, 1);
+    assert.propertyVal(layoutRender[0], "width", 3);
+    assert.equal(layoutRender[0].components[0].data.spocs.length, 0);
+  });
+
+  it("should return feed data offset by layout set prop", () => {
+    const fakeLayout = [
+      {
+        width: 3,
+        components: [
+          { type: "foo", properties: { offset: 1 }, feed: { url: "foo.com" } },
+        ],
+      },
+    ];
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_LAYOUT_UPDATE,
+      data: { layout: fakeLayout },
+    });
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_FEED_UPDATE,
+      data: { feed: FAKE_FEEDS["foo.com"], url: "foo.com" },
+    });
+    store.dispatch({ type: at.DISCOVERY_STREAM_FEEDS_UPDATE });
+
+    const { layoutRender } = selectLayoutRender({
+      state: store.getState().DiscoveryStream,
+    });
+
+    assert.deepEqual(layoutRender[0].components[0].data, {
+      recommendations: [{ id: "bar" }],
+    });
+  });
+
+  it("should return spoc result when there are more positions than spocs", () => {
+    const fakeSpocConfig = {
+      positions: [{ index: 0 }, { index: 1 }, { index: 2 }],
+    };
+    const fakeLayout = [
+      {
+        width: 3,
+        components: [
+          { type: "foo", feed: { url: "foo.com" }, spocs: fakeSpocConfig },
+        ],
+      },
+    ];
+    const fakeSpocsData = {
+      lastUpdated: 0,
+      spocs: { spocs: { items: ["fooSpoc", "barSpoc"] } },
+    };
+
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_LAYOUT_UPDATE,
+      data: { layout: fakeLayout },
+    });
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_FEED_UPDATE,
+      data: { feed: FAKE_FEEDS["foo.com"], url: "foo.com" },
+    });
+    store.dispatch({ type: at.DISCOVERY_STREAM_FEEDS_UPDATE });
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_SPOCS_UPDATE,
+      data: fakeSpocsData,
+    });
+
+    const { layoutRender } = selectLayoutRender({
+      state: store.getState().DiscoveryStream,
+    });
+
+    assert.lengthOf(layoutRender, 1);
+    assert.deepEqual(
+      layoutRender[0].components[0].data.recommendations[0],
+      "fooSpoc"
+    );
+    assert.deepEqual(
+      layoutRender[0].components[0].data.recommendations[1],
+      "barSpoc"
+    );
+    assert.deepEqual(layoutRender[0].components[0].data.recommendations[2], {
+      id: "foo",
+    });
+    assert.deepEqual(layoutRender[0].components[0].data.recommendations[3], {
+      id: "bar",
+    });
+  });
+
+  it("should return a layout with feeds of items length with positions", () => {
+    const fakeLayout = [
+      {
+        width: 3,
+        components: [
+          { type: "foo", properties: { items: 3 }, feed: { url: "foo.com" } },
+        ],
+      },
+    ];
+    const fakeRecommendations = [
+      { name: "item1" },
+      { name: "item2" },
+      { name: "item3" },
+      { name: "item4" },
+    ];
+    const fakeFeeds = {
+      "foo.com": { data: { recommendations: fakeRecommendations } },
+    };
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_LAYOUT_UPDATE,
+      data: { layout: fakeLayout },
+    });
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_FEED_UPDATE,
+      data: { feed: fakeFeeds["foo.com"], url: "foo.com" },
+    });
+    store.dispatch({ type: at.DISCOVERY_STREAM_FEEDS_UPDATE });
+
+    const { layoutRender } = selectLayoutRender({
+      state: store.getState().DiscoveryStream,
+    });
+
+    const { recommendations } = layoutRender[0].components[0].data;
+    assert.equal(recommendations.length, 4);
+    assert.equal(recommendations[0].pos, 0);
+    assert.equal(recommendations[1].pos, 1);
+    assert.equal(recommendations[2].pos, 2);
+    assert.equal(recommendations[3].pos, undefined);
+  });
+  it("should stop rendering feeds if we hit one that's not ready", () => {
+    const fakeLayout = [
+      {
+        width: 3,
+        components: [
+          { type: "foo1" },
+          { type: "foo2", properties: { items: 3 }, feed: { url: "foo2.com" } },
+          { type: "foo3", properties: { items: 3 }, feed: { url: "foo3.com" } },
+          { type: "foo4", properties: { items: 3 }, feed: { url: "foo4.com" } },
+          { type: "foo5" },
+        ],
+      },
+    ];
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_LAYOUT_UPDATE,
+      data: { layout: fakeLayout },
+    });
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_FEED_UPDATE,
+      data: { feed: { data: { recommendations: [] } }, url: "foo2.com" },
+    });
+
+    const { layoutRender } = selectLayoutRender({
+      state: store.getState().DiscoveryStream,
+    });
+
+    assert.equal(layoutRender[0].components[0].type, "foo1");
+    assert.equal(layoutRender[0].components[1].type, "foo2");
+    assert.isTrue(
+      layoutRender[0].components[2].data.recommendations[0].placeholder
+    );
+    assert.lengthOf(layoutRender[0].components, 3);
+    assert.isUndefined(layoutRender[0].components[3]);
+  });
+  it("should render everything if everything is ready", () => {
+    const fakeLayout = [
+      {
+        width: 3,
+        components: [
+          { type: "foo1" },
+          { type: "foo2", properties: { items: 3 }, feed: { url: "foo2.com" } },
+          { type: "foo3", properties: { items: 3 }, feed: { url: "foo3.com" } },
+          { type: "foo4", properties: { items: 3 }, feed: { url: "foo4.com" } },
+          { type: "foo5" },
+        ],
+      },
+    ];
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_LAYOUT_UPDATE,
+      data: { layout: fakeLayout },
+    });
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_FEED_UPDATE,
+      data: { feed: { data: { recommendations: [] } }, url: "foo2.com" },
+    });
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_FEED_UPDATE,
+      data: { feed: { data: { recommendations: [] } }, url: "foo3.com" },
+    });
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_FEED_UPDATE,
+      data: { feed: { data: { recommendations: [] } }, url: "foo4.com" },
+    });
+
+    const { layoutRender } = selectLayoutRender({
+      state: store.getState().DiscoveryStream,
+    });
+
+    assert.equal(layoutRender[0].components[0].type, "foo1");
+    assert.equal(layoutRender[0].components[1].type, "foo2");
+    assert.equal(layoutRender[0].components[2].type, "foo3");
+    assert.equal(layoutRender[0].components[3].type, "foo4");
+    assert.equal(layoutRender[0].components[4].type, "foo5");
+  });
+  it("should stop rendering feeds if we hit a not ready spoc", () => {
+    const fakeLayout = [
+      {
+        width: 3,
+        components: [
+          { type: "foo1" },
+          { type: "foo2", properties: { items: 3 }, feed: { url: "foo2.com" } },
+          {
+            type: "foo3",
+            properties: { items: 3 },
+            feed: { url: "foo3.com" },
+            spocs: { positions: [{ index: 0 }] },
+          },
+          { type: "foo4", properties: { items: 3 }, feed: { url: "foo4.com" } },
+          { type: "foo5" },
+        ],
+      },
+    ];
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_LAYOUT_UPDATE,
+      data: { layout: fakeLayout },
+    });
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_FEED_UPDATE,
+      data: { feed: { data: { recommendations: [] } }, url: "foo2.com" },
+    });
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_FEED_UPDATE,
+      data: { feed: { data: { recommendations: [] } }, url: "foo3.com" },
+    });
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_FEED_UPDATE,
+      data: { feed: { data: { recommendations: [] } }, url: "foo4.com" },
+    });
+
+    const { layoutRender } = selectLayoutRender({
+      state: store.getState().DiscoveryStream,
+    });
+
+    assert.equal(layoutRender[0].components[0].type, "foo1");
+    assert.equal(layoutRender[0].components[1].type, "foo2");
+    assert.deepEqual(layoutRender[0].components[2].data.recommendations, [
+      { placeholder: true },
+      { placeholder: true },
+      { placeholder: true },
+    ]);
+  });
+  it("should not render a spoc if there are no available spocs", () => {
+    const fakeLayout = [
+      {
+        width: 3,
+        components: [
+          { type: "foo1" },
+          { type: "foo2", properties: { items: 3 }, feed: { url: "foo2.com" } },
+          {
+            type: "foo3",
+            properties: { items: 3 },
+            feed: { url: "foo3.com" },
+            spocs: { positions: [{ index: 0 }] },
+          },
+          { type: "foo4", properties: { items: 3 }, feed: { url: "foo4.com" } },
+          { type: "foo5" },
+        ],
+      },
+    ];
+    const fakeSpocsData = { lastUpdated: 0, spocs: { spocs: [] } };
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_LAYOUT_UPDATE,
+      data: { layout: fakeLayout },
+    });
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_FEED_UPDATE,
+      data: { feed: { data: { recommendations: [] } }, url: "foo2.com" },
+    });
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_FEED_UPDATE,
+      data: {
+        feed: { data: { recommendations: [{ name: "rec" }] } },
+        url: "foo3.com",
+      },
+    });
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_FEED_UPDATE,
+      data: { feed: { data: { recommendations: [] } }, url: "foo4.com" },
+    });
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_SPOCS_UPDATE,
+      data: fakeSpocsData,
+    });
+
+    const { layoutRender } = selectLayoutRender({
+      state: store.getState().DiscoveryStream,
+    });
+
+    assert.deepEqual(layoutRender[0].components[2].data.recommendations[0], {
+      name: "rec",
+      pos: 0,
+    });
+  });
+  it("should not render a row if no components exist after filter in that row", () => {
+    const fakeLayout = [
+      {
+        width: 3,
+        components: [{ type: "TopSites" }],
+      },
+      {
+        width: 3,
+        components: [{ type: "Message" }],
+      },
+    ];
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_LAYOUT_UPDATE,
+      data: { layout: fakeLayout },
+    });
+
+    const { layoutRender } = selectLayoutRender({
+      state: store.getState().DiscoveryStream,
+      prefs: { "feeds.topsites": true },
+    });
+
+    assert.equal(layoutRender[0].components[0].type, "TopSites");
+    assert.equal(layoutRender[1], undefined);
+  });
+  it("should not render a component if filtered", () => {
+    const fakeLayout = [
+      {
+        width: 3,
+        components: [{ type: "Message" }, { type: "TopSites" }],
+      },
+    ];
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_LAYOUT_UPDATE,
+      data: { layout: fakeLayout },
+    });
+
+    const { layoutRender } = selectLayoutRender({
+      state: store.getState().DiscoveryStream,
+      prefs: { "feeds.topsites": true },
+    });
+
+    assert.equal(layoutRender[0].components[0].type, "TopSites");
+    assert.equal(layoutRender[0].components[1], undefined);
+  });
+  it("should skip rendering a spoc in position if that spoc is blocked for that session", () => {
+    const fakeLayout = [
+      {
+        width: 3,
+        components: [
+          {
+            type: "foo1",
+            properties: { items: 3 },
+            feed: { url: "foo1.com" },
+            spocs: { positions: [{ index: 0 }] },
+          },
+        ],
+      },
+    ];
+    const fakeSpocsData = {
+      lastUpdated: 0,
+      spocs: {
+        spocs: { items: [{ name: "spoc", url: "https://foo.com" }] },
+      },
+    };
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_LAYOUT_UPDATE,
+      data: { layout: fakeLayout },
+    });
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_FEED_UPDATE,
+      data: {
+        feed: { data: { recommendations: [{ name: "rec" }] } },
+        url: "foo1.com",
+      },
+    });
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_SPOCS_UPDATE,
+      data: fakeSpocsData,
+    });
+
+    const { layoutRender: layout1 } = selectLayoutRender({
+      state: store.getState().DiscoveryStream,
+    });
+
+    store.dispatch({
+      type: at.DISCOVERY_STREAM_SPOC_BLOCKED,
+      data: { url: "https://foo.com" },
+    });
+
+    const { layoutRender: layout2 } = selectLayoutRender({
+      state: store.getState().DiscoveryStream,
+    });
+
+    assert.deepEqual(layout1[0].components[0].data.recommendations[0], {
+      name: "spoc",
+      url: "https://foo.com",
+      pos: 0,
+    });
+    assert.deepEqual(layout2[0].components[0].data.recommendations[0], {
+      name: "rec",
+      pos: 0,
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/AboutPreferences.test.js b/browser/components/newtab/test/unit/lib/AboutPreferences.test.js
new file mode 100644
index 0000000000..7438d8247c
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/AboutPreferences.test.js
@@ -0,0 +1,429 @@
+/* global Services */
+import {
+  AboutPreferences,
+  PREFERENCES_LOADED_EVENT,
+} from "lib/AboutPreferences.sys.mjs";
+import {
+  actionTypes as at,
+  actionCreators as ac,
+} from "common/Actions.sys.mjs";
+import { GlobalOverrider } from "test/unit/utils";
+
+describe("AboutPreferences Feed", () => {
+  let globals;
+  let sandbox;
+  let Sections;
+  let DiscoveryStream;
+  let instance;
+
+  beforeEach(() => {
+    globals = new GlobalOverrider();
+    sandbox = globals.sandbox;
+    Sections = [];
+    DiscoveryStream = { config: { enabled: false } };
+    instance = new AboutPreferences();
+    instance.store = {
+      dispatch: sandbox.stub(),
+      getState: () => ({ Sections, DiscoveryStream }),
+    };
+    globals.set("NimbusFeatures", {
+      newtab: { getAllVariables: sandbox.stub() },
+    });
+  });
+  afterEach(() => {
+    globals.restore();
+  });
+
+  describe("#onAction", () => {
+    it("should call .init() on an INIT action", () => {
+      const stub = sandbox.stub(instance, "init");
+
+      instance.onAction({ type: at.INIT });
+
+      assert.calledOnce(stub);
+    });
+    it("should call .uninit() on an UNINIT action", () => {
+      const stub = sandbox.stub(instance, "uninit");
+
+      instance.onAction({ type: at.UNINIT });
+
+      assert.calledOnce(stub);
+    });
+    it("should call .openPreferences on SETTINGS_OPEN", () => {
+      const action = {
+        type: at.SETTINGS_OPEN,
+        _target: { browser: { ownerGlobal: { openPreferences: sinon.spy() } } },
+      };
+      instance.onAction(action);
+      assert.calledOnce(action._target.browser.ownerGlobal.openPreferences);
+    });
+    it("should call .BrowserOpenAddonsMgr with the extension id on OPEN_WEBEXT_SETTINGS", () => {
+      const action = {
+        type: at.OPEN_WEBEXT_SETTINGS,
+        data: "foo",
+        _target: {
+          browser: { ownerGlobal: { BrowserOpenAddonsMgr: sinon.spy() } },
+        },
+      };
+      instance.onAction(action);
+      assert.calledWith(
+        action._target.browser.ownerGlobal.BrowserOpenAddonsMgr,
+        "addons://detail/foo"
+      );
+    });
+  });
+  describe("#observe", () => {
+    it("should watch for about:preferences loading", () => {
+      sandbox.stub(Services.obs, "addObserver");
+
+      instance.init();
+
+      assert.calledOnce(Services.obs.addObserver);
+      assert.calledWith(
+        Services.obs.addObserver,
+        instance,
+        PREFERENCES_LOADED_EVENT
+      );
+    });
+    it("should stop watching on uninit", () => {
+      sandbox.stub(Services.obs, "removeObserver");
+
+      instance.uninit();
+
+      assert.calledOnce(Services.obs.removeObserver);
+      assert.calledWith(
+        Services.obs.removeObserver,
+        instance,
+        PREFERENCES_LOADED_EVENT
+      );
+    });
+    it("should try to render on event", async () => {
+      const stub = sandbox.stub(instance, "renderPreferences");
+      Sections.push({});
+
+      await instance.observe(window, PREFERENCES_LOADED_EVENT);
+
+      assert.calledOnce(stub);
+      assert.equal(stub.firstCall.args[0], window);
+      assert.include(stub.firstCall.args[1], Sections[0]);
+    });
+    it("Hide topstories rows select in sections if discovery stream is enabled", async () => {
+      const stub = sandbox.stub(instance, "renderPreferences");
+
+      Sections.push({
+        rowsPref: "row_pref",
+        maxRows: 3,
+        pref: { descString: "foo" },
+        learnMore: { link: "https://foo.com" },
+        id: "topstories",
+      });
+      DiscoveryStream = { config: { enabled: true } };
+
+      await instance.observe(window, PREFERENCES_LOADED_EVENT);
+
+      assert.calledOnce(stub);
+      const [, structure] = stub.firstCall.args;
+      assert.equal(structure[0].id, "search");
+      assert.equal(structure[1].id, "topsites");
+      assert.equal(structure[2].id, "topstories");
+      assert.isEmpty(structure[2].rowsPref);
+    });
+  });
+  describe("#renderPreferences", () => {
+    let node;
+    let prefStructure;
+    let Preferences;
+    let gHomePane;
+    const testRender = () =>
+      instance.renderPreferences(
+        {
+          document: {
+            createXULElement: sandbox.stub().returns(node),
+            l10n: {
+              setAttributes(el, id, args) {
+                el.setAttribute("data-l10n-id", id);
+                el.setAttribute("data-l10n-args", JSON.stringify(args));
+              },
+            },
+            createProcessingInstruction: sandbox.stub(),
+            createElementNS: sandbox.stub().callsFake((NS, el) => node),
+            getElementById: sandbox.stub().returns(node),
+            insertBefore: sandbox.stub().returnsArg(0),
+            querySelector: sandbox
+              .stub()
+              .returns({ appendChild: sandbox.stub() }),
+          },
+          Preferences,
+          gHomePane,
+        },
+        prefStructure,
+        DiscoveryStream.config
+      );
+    beforeEach(() => {
+      node = {
+        appendChild: sandbox.stub().returnsArg(0),
+        addEventListener: sandbox.stub(),
+        classList: { add: sandbox.stub(), remove: sandbox.stub() },
+        cloneNode: sandbox.stub().returnsThis(),
+        insertAdjacentElement: sandbox.stub().returnsArg(1),
+        setAttribute: sandbox.stub(),
+        remove: sandbox.stub(),
+        style: {},
+      };
+      prefStructure = [];
+      Preferences = {
+        add: sandbox.stub(),
+        get: sandbox.stub().returns({
+          on: sandbox.stub(),
+        }),
+      };
+      gHomePane = { toggleRestoreDefaultsBtn: sandbox.stub() };
+    });
+    describe("#getString", () => {
+      it("should not fail if titleString is not provided", () => {
+        prefStructure = [{ pref: {} }];
+
+        testRender();
+        assert.calledWith(
+          node.setAttribute,
+          "data-l10n-id",
+          sinon.match.typeOf("undefined")
+        );
+      });
+      it("should return the string id if titleString is just a string", () => {
+        const titleString = "foo";
+        prefStructure = [{ pref: { titleString } }];
+
+        testRender();
+        assert.calledWith(node.setAttribute, "data-l10n-id", titleString);
+      });
+      it("should set id and args if titleString is an object with id and values", () => {
+        const titleString = { id: "foo", values: { provider: "bar" } };
+        prefStructure = [{ pref: { titleString } }];
+
+        testRender();
+        assert.calledWith(node.setAttribute, "data-l10n-id", titleString.id);
+        assert.calledWith(
+          node.setAttribute,
+          "data-l10n-args",
+          JSON.stringify(titleString.values)
+        );
+      });
+    });
+    describe("#linkPref", () => {
+      it("should add a pref to the global", () => {
+        prefStructure = [{ pref: { feed: "feed" } }];
+
+        testRender();
+
+        assert.calledOnce(Preferences.add);
+      });
+      it("should skip adding if not shown", () => {
+        prefStructure = [{ shouldHidePref: true }];
+
+        testRender();
+
+        assert.notCalled(Preferences.add);
+      });
+    });
+    describe("pref icon", () => {
+      it("should default to webextension icon", () => {
+        prefStructure = [{ pref: { feed: "feed" } }];
+
+        testRender();
+
+        assert.calledWith(
+          node.setAttribute,
+          "src",
+          "chrome://activity-stream/content/data/content/assets/glyph-webextension-16.svg"
+        );
+      });
+      it("should use desired glyph icon", () => {
+        prefStructure = [{ icon: "mail", pref: { feed: "feed" } }];
+
+        testRender();
+
+        assert.calledWith(
+          node.setAttribute,
+          "src",
+          "chrome://activity-stream/content/data/content/assets/glyph-mail-16.svg"
+        );
+      });
+      it("should use specified chrome icon", () => {
+        const icon = "chrome://the/icon.svg";
+        prefStructure = [{ icon, pref: { feed: "feed" } }];
+
+        testRender();
+
+        assert.calledWith(node.setAttribute, "src", icon);
+      });
+    });
+    describe("title line", () => {
+      it("should render a title", () => {
+        const titleString = "the_title";
+        prefStructure = [{ pref: { titleString } }];
+
+        testRender();
+
+        assert.calledWith(node.setAttribute, "data-l10n-id", titleString);
+      });
+    });
+    describe("top stories", () => {
+      const href = "https://disclaimer/";
+      const eventSource = "https://disclaimer/";
+      beforeEach(() => {
+        prefStructure = [
+          {
+            id: "topstories",
+            pref: { feed: "feed", learnMore: { link: { href } } },
+            eventSource,
+          },
+        ];
+      });
+      it("should add a link for top stories", () => {
+        testRender();
+        assert.calledWith(node.setAttribute, "href", href);
+      });
+      it("should setup a user event for top stories eventSource", () => {
+        sinon.spy(instance, "setupUserEvent");
+        testRender();
+        assert.calledWith(node.addEventListener, "command");
+        assert.calledWith(instance.setupUserEvent, node, eventSource);
+      });
+      it("should setup a user event for top stories nested pref eventSource", () => {
+        sinon.spy(instance, "setupUserEvent");
+        prefStructure = [
+          {
+            id: "topstories",
+            pref: {
+              feed: "feed",
+              learnMore: { link: { href } },
+              nestedPrefs: [
+                {
+                  name: "showSponsored",
+                  titleString:
+                    "home-prefs-recommended-by-option-sponsored-stories",
+                  icon: "icon-info",
+                  eventSource: "POCKET_SPOCS",
+                },
+              ],
+            },
+          },
+        ];
+        testRender();
+        assert.calledWith(node.addEventListener, "command");
+        assert.calledWith(instance.setupUserEvent, node, "POCKET_SPOCS");
+      });
+      it("should fire store dispatch with onCommand", () => {
+        const element = {
+          addEventListener: (command, action) => {
+            // Trigger the action right away because we only care about testing the action here.
+            action({ target: { checked: true } });
+          },
+        };
+        instance.setupUserEvent(element, eventSource);
+        assert.calledWith(
+          instance.store.dispatch,
+          ac.UserEvent({
+            event: "PREF_CHANGED",
+            source: eventSource,
+            value: { menu_source: "ABOUT_PREFERENCES", status: true },
+          })
+        );
+      });
+    });
+    describe("description line", () => {
+      it("should render a description", () => {
+        const descString = "the_desc";
+        prefStructure = [{ pref: { descString } }];
+
+        testRender();
+
+        assert.calledWith(node.setAttribute, "data-l10n-id", descString);
+      });
+      it("should render rows dropdown with appropriate number", () => {
+        prefStructure = [
+          { rowsPref: "row_pref", maxRows: 3, pref: { descString: "foo" } },
+        ];
+
+        testRender();
+
+        assert.calledWith(node.setAttribute, "value", 1);
+        assert.calledWith(node.setAttribute, "value", 2);
+        assert.calledWith(node.setAttribute, "value", 3);
+      });
+    });
+    describe("nested prefs", () => {
+      const titleString = "im_nested";
+      beforeEach(() => {
+        prefStructure = [{ pref: { nestedPrefs: [{ titleString }] } }];
+      });
+      it("should render a nested pref", () => {
+        testRender();
+
+        assert.calledWith(node.setAttribute, "data-l10n-id", titleString);
+      });
+      it("should set node hidden to true", () => {
+        prefStructure[0].pref.nestedPrefs[0].hidden = true;
+
+        testRender();
+
+        assert.isTrue(node.hidden);
+      });
+      it("should add a change event", () => {
+        testRender();
+
+        assert.calledOnce(Preferences.get().on);
+        assert.calledWith(Preferences.get().on, "change");
+      });
+      it("should default node disabled to false", async () => {
+        Preferences.get = sandbox.stub().returns({
+          on: sandbox.stub(),
+          _value: true,
+        });
+
+        testRender();
+
+        assert.isFalse(node.disabled);
+      });
+      it("should default node disabled to true", async () => {
+        testRender();
+
+        assert.isTrue(node.disabled);
+      });
+      it("should set node disabled to true", async () => {
+        const pref = {
+          on: sandbox.stub(),
+          _value: true,
+        };
+        Preferences.get = sandbox.stub().returns(pref);
+
+        testRender();
+        pref._value = !pref._value;
+        await Preferences.get().on.firstCall.args[1]();
+
+        assert.isTrue(node.disabled);
+      });
+      it("should set node disabled to false", async () => {
+        const pref = {
+          on: sandbox.stub(),
+          _value: false,
+        };
+        Preferences.get = sandbox.stub().returns(pref);
+
+        testRender();
+        pref._value = !pref._value;
+        await Preferences.get().on.firstCall.args[1]();
+
+        assert.isFalse(node.disabled);
+      });
+    });
+    describe("restore defaults btn", () => {
+      it("should call toggleRestoreDefaultsBtn", () => {
+        testRender();
+
+        assert.calledOnce(gHomePane.toggleRestoreDefaultsBtn);
+      });
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/ActivityStream.test.js b/browser/components/newtab/test/unit/lib/ActivityStream.test.js
new file mode 100644
index 0000000000..c127060021
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/ActivityStream.test.js
@@ -0,0 +1,576 @@
+import { CONTENT_MESSAGE_TYPE } from "common/Actions.sys.mjs";
+import { ActivityStream, PREFS_CONFIG } from "lib/ActivityStream.sys.mjs";
+import { GlobalOverrider } from "test/unit/utils";
+
+import { DEFAULT_SITES } from "lib/DefaultSites.sys.mjs";
+import { AboutPreferences } from "lib/AboutPreferences.sys.mjs";
+import { DefaultPrefs } from "lib/ActivityStreamPrefs.sys.mjs";
+import { NewTabInit } from "lib/NewTabInit.sys.mjs";
+import { SectionsFeed } from "lib/SectionsManager.sys.mjs";
+import { RecommendationProvider } from "lib/RecommendationProvider.sys.mjs";
+import { PlacesFeed } from "lib/PlacesFeed.sys.mjs";
+import { PrefsFeed } from "lib/PrefsFeed.sys.mjs";
+import { SystemTickFeed } from "lib/SystemTickFeed.sys.mjs";
+import { TelemetryFeed } from "lib/TelemetryFeed.sys.mjs";
+import { FaviconFeed } from "lib/FaviconFeed.sys.mjs";
+import { TopSitesFeed } from "lib/TopSitesFeed.sys.mjs";
+import { TopStoriesFeed } from "lib/TopStoriesFeed.sys.mjs";
+import { HighlightsFeed } from "lib/HighlightsFeed.sys.mjs";
+import { DiscoveryStreamFeed } from "lib/DiscoveryStreamFeed.sys.mjs";
+
+import { LinksCache } from "lib/LinksCache.sys.mjs";
+import { PersistentCache } from "lib/PersistentCache.sys.mjs";
+import { DownloadsManager } from "lib/DownloadsManager.sys.mjs";
+
+describe("ActivityStream", () => {
+  let sandbox;
+  let as;
+  function FakeStore() {
+    return { init: () => {}, uninit: () => {}, feeds: { get: () => {} } };
+  }
+
+  let globals;
+  beforeEach(() => {
+    globals = new GlobalOverrider();
+    globals.set({
+      Store: FakeStore,
+
+      DEFAULT_SITES,
+      AboutPreferences,
+      DefaultPrefs,
+      NewTabInit,
+      SectionsFeed,
+      RecommendationProvider,
+      PlacesFeed,
+      PrefsFeed,
+      SystemTickFeed,
+      TelemetryFeed,
+      FaviconFeed,
+      TopSitesFeed,
+      TopStoriesFeed,
+      HighlightsFeed,
+      DiscoveryStreamFeed,
+
+      LinksCache,
+      PersistentCache,
+      DownloadsManager,
+    });
+
+    as = new ActivityStream();
+    sandbox = sinon.createSandbox();
+    sandbox.stub(as.store, "init");
+    sandbox.stub(as.store, "uninit");
+    sandbox.stub(as._defaultPrefs, "init");
+    PREFS_CONFIG.get("feeds.system.topstories").value = undefined;
+  });
+
+  afterEach(() => {
+    sandbox.restore();
+    globals.restore();
+  });
+
+  it("should exist", () => {
+    assert.ok(ActivityStream);
+  });
+  it("should initialize with .initialized=false", () => {
+    assert.isFalse(as.initialized, ".initialized");
+  });
+  describe("#init", () => {
+    beforeEach(() => {
+      as.init();
+    });
+    it("should initialize default prefs", () => {
+      assert.calledOnce(as._defaultPrefs.init);
+    });
+    it("should set .initialized to true", () => {
+      assert.isTrue(as.initialized, ".initialized");
+    });
+    it("should call .store.init", () => {
+      assert.calledOnce(as.store.init);
+    });
+    it("should pass to Store an INIT event for content", () => {
+      as.init();
+
+      const [, action] = as.store.init.firstCall.args;
+      assert.equal(action.meta.to, CONTENT_MESSAGE_TYPE);
+    });
+    it("should pass to Store an UNINIT event", () => {
+      as.init();
+
+      const [, , action] = as.store.init.firstCall.args;
+      assert.equal(action.type, "UNINIT");
+    });
+    it("should clear old default discoverystream config pref", () => {
+      sandbox.stub(global.Services.prefs, "prefHasUserValue").returns(true);
+      sandbox
+        .stub(global.Services.prefs, "getStringPref")
+        .returns(
+          `{"api_key_pref":"extensions.pocket.oAuthConsumerKey","enabled":false,"show_spocs":true,"layout_endpoint":"https://getpocket.cdn.mozilla.net/v3/newtab/layout?version=1&consumer_key=$apiKey&layout_variant=basic"}`
+        );
+      sandbox.stub(global.Services.prefs, "clearUserPref");
+
+      as.init();
+
+      assert.calledWith(
+        global.Services.prefs.clearUserPref,
+        "browser.newtabpage.activity-stream.discoverystream.config"
+      );
+    });
+    it("should call addObserver for the app locales", () => {
+      sandbox.stub(global.Services.obs, "addObserver");
+      as.init();
+      assert.calledWith(
+        global.Services.obs.addObserver,
+        as,
+        "intl:app-locales-changed"
+      );
+    });
+  });
+  describe("#uninit", () => {
+    beforeEach(() => {
+      as.init();
+      as.uninit();
+    });
+    it("should set .initialized to false", () => {
+      assert.isFalse(as.initialized, ".initialized");
+    });
+    it("should call .store.uninit", () => {
+      assert.calledOnce(as.store.uninit);
+    });
+    it("should call removeObserver for the region", () => {
+      sandbox.stub(global.Services.obs, "removeObserver");
+      as.geo = "";
+      as.uninit();
+      assert.calledWith(
+        global.Services.obs.removeObserver,
+        as,
+        global.Region.REGION_TOPIC
+      );
+    });
+    it("should call removeObserver for the app locales", () => {
+      sandbox.stub(global.Services.obs, "removeObserver");
+      as.uninit();
+      assert.calledWith(
+        global.Services.obs.removeObserver,
+        as,
+        "intl:app-locales-changed"
+      );
+    });
+  });
+  describe("#observe", () => {
+    it("should call _updateDynamicPrefs from observe", () => {
+      sandbox.stub(as, "_updateDynamicPrefs");
+      as.observe(undefined, global.Region.REGION_TOPIC);
+      assert.calledOnce(as._updateDynamicPrefs);
+    });
+  });
+  describe("feeds", () => {
+    it("should create a NewTabInit feed", () => {
+      const feed = as.feeds.get("feeds.newtabinit")();
+      assert.ok(feed, "feed should exist");
+    });
+    it("should create a Places feed", () => {
+      const feed = as.feeds.get("feeds.places")();
+      assert.ok(feed, "feed should exist");
+    });
+    it("should create a TopSites feed", () => {
+      const feed = as.feeds.get("feeds.system.topsites")();
+      assert.ok(feed, "feed should exist");
+    });
+    it("should create a Telemetry feed", () => {
+      const feed = as.feeds.get("feeds.telemetry")();
+      assert.ok(feed, "feed should exist");
+    });
+    it("should create a Prefs feed", () => {
+      const feed = as.feeds.get("feeds.prefs")();
+      assert.ok(feed, "feed should exist");
+    });
+    it("should create a HighlightsFeed feed", () => {
+      const feed = as.feeds.get("feeds.section.highlights")();
+      assert.ok(feed, "feed should exist");
+    });
+    it("should create a TopStoriesFeed feed", () => {
+      const feed = as.feeds.get("feeds.system.topstories")();
+      assert.ok(feed, "feed should exist");
+    });
+    it("should create a AboutPreferences feed", () => {
+      const feed = as.feeds.get("feeds.aboutpreferences")();
+      assert.ok(feed, "feed should exist");
+    });
+    it("should create a SectionsFeed", () => {
+      const feed = as.feeds.get("feeds.sections")();
+      assert.ok(feed, "feed should exist");
+    });
+    it("should create a SystemTick feed", () => {
+      const feed = as.feeds.get("feeds.systemtick")();
+      assert.ok(feed, "feed should exist");
+    });
+    it("should create a Favicon feed", () => {
+      const feed = as.feeds.get("feeds.favicon")();
+      assert.ok(feed, "feed should exist");
+    });
+    it("should create a RecommendationProvider feed", () => {
+      const feed = as.feeds.get("feeds.recommendationprovider")();
+      assert.ok(feed, "feed should exist");
+    });
+    it("should create a DiscoveryStreamFeed feed", () => {
+      const feed = as.feeds.get("feeds.discoverystreamfeed")();
+      assert.ok(feed, "feed should exist");
+    });
+  });
+  describe("_migratePref", () => {
+    it("should migrate a pref if the user has set a custom value", () => {
+      sandbox.stub(global.Services.prefs, "prefHasUserValue").returns(true);
+      sandbox.stub(global.Services.prefs, "getPrefType").returns("integer");
+      sandbox.stub(global.Services.prefs, "getIntPref").returns(10);
+      as._migratePref("oldPrefName", result => assert.equal(10, result));
+    });
+    it("should not migrate a pref if the user has not set a custom value", () => {
+      // we bailed out early so we don't check the pref type later
+      sandbox.stub(global.Services.prefs, "prefHasUserValue").returns(false);
+      sandbox.stub(global.Services.prefs, "getPrefType");
+      as._migratePref("oldPrefName");
+      assert.notCalled(global.Services.prefs.getPrefType);
+    });
+    it("should use the proper pref getter for each type", () => {
+      sandbox.stub(global.Services.prefs, "prefHasUserValue").returns(true);
+
+      // Integer
+      sandbox.stub(global.Services.prefs, "getIntPref");
+      sandbox.stub(global.Services.prefs, "getPrefType").returns("integer");
+      as._migratePref("oldPrefName", () => {});
+      assert.calledWith(global.Services.prefs.getIntPref, "oldPrefName");
+
+      // Boolean
+      sandbox.stub(global.Services.prefs, "getBoolPref");
+      global.Services.prefs.getPrefType.returns("boolean");
+      as._migratePref("oldPrefName", () => {});
+      assert.calledWith(global.Services.prefs.getBoolPref, "oldPrefName");
+
+      // String
+      sandbox.stub(global.Services.prefs, "getStringPref");
+      global.Services.prefs.getPrefType.returns("string");
+      as._migratePref("oldPrefName", () => {});
+      assert.calledWith(global.Services.prefs.getStringPref, "oldPrefName");
+    });
+    it("should clear the old pref after setting the new one", () => {
+      sandbox.stub(global.Services.prefs, "prefHasUserValue").returns(true);
+      sandbox.stub(global.Services.prefs, "clearUserPref");
+      sandbox.stub(global.Services.prefs, "getPrefType").returns("integer");
+      as._migratePref("oldPrefName", () => {});
+      assert.calledWith(global.Services.prefs.clearUserPref, "oldPrefName");
+    });
+  });
+  describe("discoverystream.region-basic-layout config", () => {
+    let getStringPrefStub;
+    beforeEach(() => {
+      getStringPrefStub = sandbox.stub(global.Services.prefs, "getStringPref");
+      sandbox.stub(global.Region, "home").get(() => "CA");
+      sandbox
+        .stub(global.Services.locale, "appLocaleAsBCP47")
+        .get(() => "en-CA");
+    });
+    it("should enable 7 row layout pref if no basic config is set and no geo is set", () => {
+      getStringPrefStub
+        .withArgs(
+          "browser.newtabpage.activity-stream.discoverystream.region-basic-config"
+        )
+        .returns("");
+      sandbox.stub(global.Region, "home").get(() => "");
+
+      as._updateDynamicPrefs();
+
+      assert.isFalse(
+        PREFS_CONFIG.get("discoverystream.region-basic-layout").value
+      );
+    });
+    it("should enable 1 row layout pref based on region layout pref", () => {
+      getStringPrefStub
+        .withArgs(
+          "browser.newtabpage.activity-stream.discoverystream.region-basic-config"
+        )
+        .returns("CA");
+
+      as._updateDynamicPrefs();
+
+      assert.isTrue(
+        PREFS_CONFIG.get("discoverystream.region-basic-layout").value
+      );
+    });
+    it("should enable 7 row layout pref based on region layout pref", () => {
+      getStringPrefStub
+        .withArgs(
+          "browser.newtabpage.activity-stream.discoverystream.region-basic-config"
+        )
+        .returns("");
+
+      as._updateDynamicPrefs();
+
+      assert.isFalse(
+        PREFS_CONFIG.get("discoverystream.region-basic-layout").value
+      );
+    });
+  });
+  describe("_updateDynamicPrefs topstories default value", () => {
+    let getVariableStub;
+    let getBoolPrefStub;
+    let appLocaleAsBCP47Stub;
+    beforeEach(() => {
+      getVariableStub = sandbox.stub(
+        global.NimbusFeatures.pocketNewtab,
+        "getVariable"
+      );
+      appLocaleAsBCP47Stub = sandbox.stub(
+        global.Services.locale,
+        "appLocaleAsBCP47"
+      );
+
+      getBoolPrefStub = sandbox.stub(global.Services.prefs, "getBoolPref");
+      getBoolPrefStub
+        .withArgs("browser.newtabpage.activity-stream.feeds.section.topstories")
+        .returns(true);
+
+      appLocaleAsBCP47Stub.get(() => "en-US");
+
+      sandbox.stub(global.Region, "home").get(() => "US");
+
+      getVariableStub.withArgs("regionStoriesConfig").returns("US,CA");
+    });
+    it("should be false with no geo/locale", () => {
+      appLocaleAsBCP47Stub.get(() => "");
+      sandbox.stub(global.Region, "home").get(() => "");
+
+      as._updateDynamicPrefs();
+
+      assert.isFalse(PREFS_CONFIG.get("feeds.system.topstories").value);
+    });
+    it("should be false with no geo but an allowed locale", () => {
+      appLocaleAsBCP47Stub.get(() => "");
+      sandbox.stub(global.Region, "home").get(() => "");
+      appLocaleAsBCP47Stub.get(() => "en-US");
+      getVariableStub
+        .withArgs("localeListConfig")
+        .returns("en-US,en-CA,en-GB")
+        // We only have this pref set to trigger a close to real situation.
+        .withArgs(
+          "browser.newtabpage.activity-stream.discoverystream.region-stories-block"
+        )
+        .returns("FR");
+
+      as._updateDynamicPrefs();
+
+      assert.isFalse(PREFS_CONFIG.get("feeds.system.topstories").value);
+    });
+    it("should be false with unexpected geo", () => {
+      sandbox.stub(global.Region, "home").get(() => "NOGEO");
+
+      as._updateDynamicPrefs();
+
+      assert.isFalse(PREFS_CONFIG.get("feeds.system.topstories").value);
+    });
+    it("should be false with expected geo and unexpected locale", () => {
+      appLocaleAsBCP47Stub.get(() => "no-LOCALE");
+
+      as._updateDynamicPrefs();
+
+      assert.isFalse(PREFS_CONFIG.get("feeds.system.topstories").value);
+    });
+    it("should be true with expected geo and locale", () => {
+      as._updateDynamicPrefs();
+      assert.isTrue(PREFS_CONFIG.get("feeds.system.topstories").value);
+    });
+    it("should be false after expected geo and locale then unexpected", () => {
+      sandbox
+        .stub(global.Region, "home")
+        .onFirstCall()
+        .get(() => "US")
+        .onSecondCall()
+        .get(() => "NOGEO");
+
+      as._updateDynamicPrefs();
+      as._updateDynamicPrefs();
+
+      assert.isFalse(PREFS_CONFIG.get("feeds.system.topstories").value);
+    });
+    it("should be true with updated pref change", () => {
+      appLocaleAsBCP47Stub.get(() => "en-GB");
+      sandbox.stub(global.Region, "home").get(() => "GB");
+      getVariableStub.withArgs("regionStoriesConfig").returns("GB");
+
+      as._updateDynamicPrefs();
+
+      assert.isTrue(PREFS_CONFIG.get("feeds.system.topstories").value);
+    });
+    it("should be true with allowed locale in non US region", () => {
+      appLocaleAsBCP47Stub.get(() => "en-CA");
+      sandbox.stub(global.Region, "home").get(() => "DE");
+      getVariableStub.withArgs("localeListConfig").returns("en-US,en-CA,en-GB");
+
+      as._updateDynamicPrefs();
+
+      assert.isTrue(PREFS_CONFIG.get("feeds.system.topstories").value);
+    });
+  });
+  describe("_updateDynamicPrefs topstories delayed default value", () => {
+    let clock;
+    beforeEach(() => {
+      clock = sinon.useFakeTimers();
+
+      // Have addObserver cause prefHasUserValue to now return true then observe
+      sandbox
+        .stub(global.Services.obs, "addObserver")
+        .callsFake((pref, obs) => {
+          setTimeout(() => {
+            Services.obs.notifyObservers("US", "browser-region-updated");
+          });
+        });
+    });
+    afterEach(() => clock.restore());
+
+    it("should set false with unexpected geo", () => {
+      sandbox
+        .stub(global.Services.prefs, "getStringPref")
+        .withArgs("browser.search.region")
+        .returns("NOGEO");
+
+      as._updateDynamicPrefs();
+
+      clock.tick(1);
+
+      assert.isFalse(PREFS_CONFIG.get("feeds.system.topstories").value);
+    });
+    it("should set true with expected geo and locale", () => {
+      sandbox
+        .stub(global.NimbusFeatures.pocketNewtab, "getVariable")
+        .withArgs("regionStoriesConfig")
+        .returns("US");
+
+      sandbox.stub(global.Services.prefs, "getBoolPref").returns(true);
+      sandbox
+        .stub(global.Services.locale, "appLocaleAsBCP47")
+        .get(() => "en-US");
+
+      as._updateDynamicPrefs();
+      clock.tick(1);
+
+      assert.isTrue(PREFS_CONFIG.get("feeds.system.topstories").value);
+    });
+    it("should not change default even with expected geo and locale", () => {
+      as._defaultPrefs.set("feeds.system.topstories", false);
+      sandbox
+        .stub(global.Services.prefs, "getStringPref")
+        .withArgs(
+          "browser.newtabpage.activity-stream.discoverystream.region-stories-config"
+        )
+        .returns("US");
+
+      sandbox
+        .stub(global.Services.locale, "appLocaleAsBCP47")
+        .get(() => "en-US");
+
+      as._updateDynamicPrefs();
+      clock.tick(1);
+
+      assert.isFalse(PREFS_CONFIG.get("feeds.system.topstories").value);
+    });
+    it("should set false with geo blocked", () => {
+      sandbox
+        .stub(global.Services.prefs, "getStringPref")
+        .withArgs(
+          "browser.newtabpage.activity-stream.discoverystream.region-stories-config"
+        )
+        .returns("US")
+        .withArgs(
+          "browser.newtabpage.activity-stream.discoverystream.region-stories-block"
+        )
+        .returns("US");
+
+      sandbox.stub(global.Services.prefs, "getBoolPref").returns(true);
+      sandbox
+        .stub(global.Services.locale, "appLocaleAsBCP47")
+        .get(() => "en-US");
+
+      as._updateDynamicPrefs();
+      clock.tick(1);
+
+      assert.isFalse(PREFS_CONFIG.get("feeds.system.topstories").value);
+    });
+  });
+  describe("telemetry reporting on init failure", () => {
+    it("should send a ping on init error", () => {
+      as = new ActivityStream();
+      const telemetry = { handleUndesiredEvent: sandbox.spy() };
+      sandbox.stub(as.store, "init").throws();
+      sandbox.stub(as.store.feeds, "get").returns(telemetry);
+      try {
+        as.init();
+      } catch (e) {}
+      assert.calledOnce(telemetry.handleUndesiredEvent);
+    });
+  });
+
+  describe("searchs shortcuts shouldPin pref", () => {
+    const SEARCH_SHORTCUTS_SEARCH_ENGINES_PREF =
+      "improvesearch.topSiteSearchShortcuts.searchEngines";
+    let stub;
+
+    beforeEach(() => {
+      stub = sandbox.stub(global.Region, "home");
+    });
+
+    it("should be an empty string when no geo is available", () => {
+      stub.get(() => "");
+      as._updateDynamicPrefs();
+      assert.equal(
+        PREFS_CONFIG.get(SEARCH_SHORTCUTS_SEARCH_ENGINES_PREF).value,
+        ""
+      );
+    });
+
+    it("should be 'baidu' in China", () => {
+      stub.get(() => "CN");
+      as._updateDynamicPrefs();
+      assert.equal(
+        PREFS_CONFIG.get(SEARCH_SHORTCUTS_SEARCH_ENGINES_PREF).value,
+        "baidu"
+      );
+    });
+
+    it("should be 'yandex' in Russia, Belarus, Kazakhstan, and Turkey", () => {
+      const geos = ["BY", "KZ", "RU", "TR"];
+      for (const geo of geos) {
+        stub.get(() => geo);
+        as._updateDynamicPrefs();
+        assert.equal(
+          PREFS_CONFIG.get(SEARCH_SHORTCUTS_SEARCH_ENGINES_PREF).value,
+          "yandex"
+        );
+      }
+    });
+
+    it("should be 'google,amazon' in Germany, France, the UK, Japan, Italy, and the US", () => {
+      const geos = ["DE", "FR", "GB", "IT", "JP", "US"];
+      for (const geo of geos) {
+        stub.returns(geo);
+        as._updateDynamicPrefs();
+        assert.equal(
+          PREFS_CONFIG.get(SEARCH_SHORTCUTS_SEARCH_ENGINES_PREF).value,
+          "google,amazon"
+        );
+      }
+    });
+
+    it("should be 'google' elsewhere", () => {
+      // A selection of other geos
+      const geos = ["BR", "CA", "ES", "ID", "IN"];
+      for (const geo of geos) {
+        stub.get(() => geo);
+        as._updateDynamicPrefs();
+        assert.equal(
+          PREFS_CONFIG.get(SEARCH_SHORTCUTS_SEARCH_ENGINES_PREF).value,
+          "google"
+        );
+      }
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/ActivityStreamMessageChannel.test.js b/browser/components/newtab/test/unit/lib/ActivityStreamMessageChannel.test.js
new file mode 100644
index 0000000000..4bea86331d
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/ActivityStreamMessageChannel.test.js
@@ -0,0 +1,445 @@
+import {
+  actionCreators as ac,
+  actionTypes as at,
+} from "common/Actions.sys.mjs";
+import {
+  ActivityStreamMessageChannel,
+  DEFAULT_OPTIONS,
+} from "lib/ActivityStreamMessageChannel.sys.mjs";
+import { addNumberReducer, GlobalOverrider } from "test/unit/utils";
+import { applyMiddleware, createStore } from "redux";
+
+const OPTIONS = [
+  "pageURL, outgoingMessageName",
+  "incomingMessageName",
+  "dispatch",
+];
+
+// Create an object containing details about a tab as expected within
+// the loaded tabs map in ActivityStreamMessageChannel.jsm.
+function getTabDetails(portID, url = "about:newtab", extraArgs = {}) {
+  let actor = {
+    portID,
+    sendAsyncMessage: sinon.spy(),
+  };
+  let browser = {
+    getAttribute: () => (extraArgs.preloaded ? "preloaded" : ""),
+    ownerGlobal: {},
+  };
+  let browsingContext = {
+    top: {
+      embedderElement: browser,
+    },
+  };
+
+  let data = {
+    data: {
+      actor,
+      browser,
+      browsingContext,
+      portID,
+      url,
+    },
+    target: {
+      browsingContext,
+    },
+  };
+
+  if (extraArgs.loaded) {
+    data.data.loaded = extraArgs.loaded;
+  }
+  if (extraArgs.simulated) {
+    data.data.simulated = extraArgs.simulated;
+  }
+
+  return data;
+}
+
+describe("ActivityStreamMessageChannel", () => {
+  let globals;
+  let dispatch;
+  let mm;
+  beforeEach(() => {
+    globals = new GlobalOverrider();
+    globals.set("AboutNewTab", {
+      reset: globals.sandbox.spy(),
+    });
+    globals.set("AboutHomeStartupCache", { onPreloadedNewTabMessage() {} });
+    globals.set("AboutNewTabParent", {
+      flushQueuedMessagesFromContent: globals.sandbox.stub(),
+    });
+
+    dispatch = globals.sandbox.spy();
+    mm = new ActivityStreamMessageChannel({ dispatch });
+
+    assert.ok(mm.loadedTabs, []);
+
+    let loadedTabs = new Map();
+    let sandbox = sinon.createSandbox();
+    sandbox.stub(mm, "loadedTabs").get(() => loadedTabs);
+  });
+
+  afterEach(() => globals.restore());
+
+  describe("portID validation", () => {
+    let sandbox;
+    beforeEach(() => {
+      sandbox = sinon.createSandbox();
+      sandbox.spy(global.console, "error");
+    });
+    afterEach(() => {
+      sandbox.restore();
+    });
+    it("should log errors for an invalid portID", () => {
+      mm.validatePortID({});
+      mm.validatePortID({});
+      mm.validatePortID({});
+
+      assert.equal(global.console.error.callCount, 3);
+    });
+  });
+
+  it("should exist", () => {
+    assert.ok(ActivityStreamMessageChannel);
+  });
+  it("should apply default options", () => {
+    mm = new ActivityStreamMessageChannel();
+    OPTIONS.forEach(o => assert.equal(mm[o], DEFAULT_OPTIONS[o], o));
+  });
+  it("should add options", () => {
+    const options = {
+      dispatch: () => {},
+      pageURL: "FOO.html",
+      outgoingMessageName: "OUT",
+      incomingMessageName: "IN",
+    };
+    mm = new ActivityStreamMessageChannel(options);
+    OPTIONS.forEach(o => assert.equal(mm[o], options[o], o));
+  });
+  it("should throw an error if no dispatcher was provided", () => {
+    mm = new ActivityStreamMessageChannel();
+    assert.throws(() => mm.dispatch({ type: "FOO" }));
+  });
+  describe("Creating/destroying the channel", () => {
+    describe("#simulateMessagesForExistingTabs", () => {
+      beforeEach(() => {
+        sinon.stub(mm, "onActionFromContent");
+      });
+      it("should simulate init for existing ports", () => {
+        let msg1 = getTabDetails("inited", "about:monkeys", {
+          simulated: true,
+        });
+        mm.loadedTabs.set(msg1.data.browser, msg1.data);
+
+        let msg2 = getTabDetails("loaded", "about:sheep", {
+          simulated: true,
+        });
+        mm.loadedTabs.set(msg2.data.browser, msg2.data);
+
+        mm.simulateMessagesForExistingTabs();
+
+        assert.calledWith(mm.onActionFromContent.firstCall, {
+          type: at.NEW_TAB_INIT,
+          data: msg1.data,
+        });
+        assert.calledWith(mm.onActionFromContent.secondCall, {
+          type: at.NEW_TAB_INIT,
+          data: msg2.data,
+        });
+      });
+      it("should simulate load for loaded ports", () => {
+        let msg3 = getTabDetails("foo", null, {
+          preloaded: true,
+          loaded: true,
+        });
+        mm.loadedTabs.set(msg3.data.browser, msg3.data);
+
+        mm.simulateMessagesForExistingTabs();
+
+        assert.calledWith(
+          mm.onActionFromContent,
+          { type: at.NEW_TAB_LOAD },
+          "foo"
+        );
+      });
+      it("should set renderLayers on preloaded browsers after load", () => {
+        let msg4 = getTabDetails("foo", null, {
+          preloaded: true,
+          loaded: true,
+        });
+        msg4.data.browser.ownerGlobal = {
+          STATE_MAXIMIZED: 1,
+          STATE_MINIMIZED: 2,
+          STATE_NORMAL: 3,
+          STATE_FULLSCREEN: 4,
+          windowState: 3,
+          isFullyOccluded: false,
+        };
+        mm.loadedTabs.set(msg4.data.browser, msg4.data);
+        mm.simulateMessagesForExistingTabs();
+        assert.equal(msg4.data.browser.renderLayers, true);
+      });
+      it("should flush queued messages from content when doing the simulation", () => {
+        assert.notCalled(
+          global.AboutNewTabParent.flushQueuedMessagesFromContent
+        );
+        mm.simulateMessagesForExistingTabs();
+        assert.calledOnce(
+          global.AboutNewTabParent.flushQueuedMessagesFromContent
+        );
+      });
+    });
+  });
+  describe("Message handling", () => {
+    describe("#getTargetById", () => {
+      it("should get an id if it exists", () => {
+        let msg = getTabDetails("foo:1");
+        mm.loadedTabs.set(msg.data.browser, msg.data);
+        assert.equal(mm.getTargetById("foo:1"), msg.data.actor);
+      });
+      it("should return null if the target doesn't exist", () => {
+        let msg = getTabDetails("foo:2");
+        mm.loadedTabs.set(msg.data.browser, msg.data);
+        assert.equal(mm.getTargetById("bar:3"), null);
+      });
+    });
+    describe("#getPreloadedActors", () => {
+      it("should get a preloaded actor if it exists", () => {
+        let msg = getTabDetails("foo:3", null, { preloaded: true });
+        mm.loadedTabs.set(msg.data.browser, msg.data);
+        assert.equal(mm.getPreloadedActors()[0].portID, "foo:3");
+      });
+      it("should get all the preloaded actors across windows if they exist", () => {
+        let msg = getTabDetails("foo:4a", null, { preloaded: true });
+        mm.loadedTabs.set(msg.data.browser, msg.data);
+        msg = getTabDetails("foo:4b", null, { preloaded: true });
+        mm.loadedTabs.set(msg.data.browser, msg.data);
+        assert.equal(mm.getPreloadedActors().length, 2);
+      });
+      it("should return null if there is no preloaded actor", () => {
+        let msg = getTabDetails("foo:5");
+        mm.loadedTabs.set(msg.data.browser, msg.data);
+        assert.equal(mm.getPreloadedActors(), null);
+      });
+    });
+    describe("#onNewTabInit", () => {
+      it("should dispatch a NEW_TAB_INIT action", () => {
+        let msg = getTabDetails("foo", "about:monkeys");
+        sinon.stub(mm, "onActionFromContent");
+
+        mm.onNewTabInit(msg, msg.data);
+
+        assert.calledWith(mm.onActionFromContent, {
+          type: at.NEW_TAB_INIT,
+          data: msg.data,
+        });
+      });
+    });
+    describe("#onNewTabLoad", () => {
+      it("should dispatch a NEW_TAB_LOAD action", () => {
+        let msg = getTabDetails("foo", null, { preloaded: true });
+        mm.loadedTabs.set(msg.data.browser, msg.data);
+        sinon.stub(mm, "onActionFromContent");
+        mm.onNewTabLoad({ target: msg.target }, msg.data);
+        assert.calledWith(
+          mm.onActionFromContent,
+          { type: at.NEW_TAB_LOAD },
+          "foo"
+        );
+      });
+    });
+    describe("#onNewTabUnload", () => {
+      it("should dispatch a NEW_TAB_UNLOAD action", () => {
+        let msg = getTabDetails("foo");
+        mm.loadedTabs.set(msg.data.browser, msg.data);
+        sinon.stub(mm, "onActionFromContent");
+        mm.onNewTabUnload({ target: msg.target }, msg.data);
+        assert.calledWith(
+          mm.onActionFromContent,
+          { type: at.NEW_TAB_UNLOAD },
+          "foo"
+        );
+      });
+    });
+    describe("#onMessage", () => {
+      let sandbox;
+      beforeEach(() => {
+        sandbox = sinon.createSandbox();
+        sandbox.spy(global.console, "error");
+      });
+      afterEach(() => sandbox.restore());
+      it("return early when tab details are not present", () => {
+        let msg = getTabDetails("foo");
+        sinon.stub(mm, "onActionFromContent");
+        mm.onMessage(msg, msg.data);
+        assert.notCalled(mm.onActionFromContent);
+      });
+      it("should report an error if the msg.data is missing", () => {
+        let msg = getTabDetails("foo");
+        mm.loadedTabs.set(msg.data.browser, msg.data);
+        let tabDetails = msg.data;
+        delete msg.data;
+        mm.onMessage(msg, tabDetails);
+        assert.calledOnce(global.console.error);
+      });
+      it("should report an error if the msg.data.type is missing", () => {
+        let msg = getTabDetails("foo");
+        mm.loadedTabs.set(msg.data.browser, msg.data);
+        msg.data = "foo";
+        mm.onMessage(msg, msg.data);
+        assert.calledOnce(global.console.error);
+      });
+      it("should call onActionFromContent", () => {
+        sinon.stub(mm, "onActionFromContent");
+        let msg = getTabDetails("foo");
+        mm.loadedTabs.set(msg.data.browser, msg.data);
+        let action = {
+          data: { data: {}, type: "FOO" },
+          target: msg.target,
+        };
+        const expectedAction = {
+          type: action.data.type,
+          data: action.data.data,
+          _target: { browser: msg.data.browser },
+        };
+        mm.onMessage(action, msg.data);
+        assert.calledWith(mm.onActionFromContent, expectedAction, "foo");
+      });
+    });
+  });
+  describe("Sending and broadcasting", () => {
+    describe("#send", () => {
+      it("should send a message on the right port", () => {
+        let msg = getTabDetails("foo:6");
+        mm.loadedTabs.set(msg.data.browser, msg.data);
+        const action = ac.AlsoToOneContent({ type: "HELLO" }, "foo:6");
+        mm.send(action);
+        assert.calledWith(
+          msg.data.actor.sendAsyncMessage,
+          DEFAULT_OPTIONS.outgoingMessageName,
+          action
+        );
+      });
+      it("should not throw if the target isn't around", () => {
+        // port is not added to the channel
+        const action = ac.AlsoToOneContent({ type: "HELLO" }, "foo:7");
+
+        assert.doesNotThrow(() => mm.send(action));
+      });
+    });
+    describe("#broadcast", () => {
+      it("should send a message on the channel", () => {
+        let msg = getTabDetails("foo:8");
+        mm.loadedTabs.set(msg.data.browser, msg.data);
+        const action = ac.BroadcastToContent({ type: "HELLO" });
+        mm.broadcast(action);
+        assert.calledWith(
+          msg.data.actor.sendAsyncMessage,
+          DEFAULT_OPTIONS.outgoingMessageName,
+          action
+        );
+      });
+    });
+    describe("#preloaded browser", () => {
+      it("should send the message to the preloaded browser if there's data and a preloaded browser exists", () => {
+        let msg = getTabDetails("foo:9", null, { preloaded: true });
+        mm.loadedTabs.set(msg.data.browser, msg.data);
+        const action = ac.AlsoToPreloaded({ type: "HELLO", data: 10 });
+        mm.sendToPreloaded(action);
+        assert.calledWith(
+          msg.data.actor.sendAsyncMessage,
+          DEFAULT_OPTIONS.outgoingMessageName,
+          action
+        );
+      });
+      it("should send the message to all the preloaded browsers if there's data and they exist", () => {
+        let msg1 = getTabDetails("foo:10a", null, { preloaded: true });
+        mm.loadedTabs.set(msg1.data.browser, msg1.data);
+
+        let msg2 = getTabDetails("foo:10b", null, { preloaded: true });
+        mm.loadedTabs.set(msg2.data.browser, msg2.data);
+
+        mm.sendToPreloaded(ac.AlsoToPreloaded({ type: "HELLO", data: 10 }));
+        assert.calledOnce(msg1.data.actor.sendAsyncMessage);
+        assert.calledOnce(msg2.data.actor.sendAsyncMessage);
+      });
+      it("should not send the message to the preloaded browser if there's no data and a preloaded browser does not exists", () => {
+        let msg = getTabDetails("foo:11");
+        mm.loadedTabs.set(msg.data.browser, msg.data);
+        const action = ac.AlsoToPreloaded({ type: "HELLO" });
+        mm.sendToPreloaded(action);
+        assert.notCalled(msg.data.actor.sendAsyncMessage);
+      });
+    });
+  });
+  describe("Handling actions", () => {
+    describe("#onActionFromContent", () => {
+      beforeEach(() => mm.onActionFromContent({ type: "FOO" }, "foo:12"));
+      it("should dispatch a AlsoToMain action", () => {
+        assert.calledOnce(dispatch);
+        const [action] = dispatch.firstCall.args;
+        assert.equal(action.type, "FOO", "action.type");
+      });
+      it("should have the right fromTarget", () => {
+        const [action] = dispatch.firstCall.args;
+        assert.equal(action.meta.fromTarget, "foo:12", "meta.fromTarget");
+      });
+    });
+    describe("#middleware", () => {
+      let store;
+      beforeEach(() => {
+        store = createStore(addNumberReducer, applyMiddleware(mm.middleware));
+      });
+      it("should just call next if no channel is found", () => {
+        store.dispatch({ type: "ADD", data: 10 });
+        assert.equal(store.getState(), 10);
+      });
+      it("should call .send but not affect the main store if an OnlyToOneContent action is dispatched", () => {
+        sinon.stub(mm, "send");
+        const action = ac.OnlyToOneContent({ type: "ADD", data: 10 }, "foo");
+
+        store.dispatch(action);
+
+        assert.calledWith(mm.send, action);
+        assert.equal(store.getState(), 0);
+      });
+      it("should call .send and update the main store if an AlsoToOneContent action is dispatched", () => {
+        sinon.stub(mm, "send");
+        const action = ac.AlsoToOneContent({ type: "ADD", data: 10 }, "foo");
+
+        store.dispatch(action);
+
+        assert.calledWith(mm.send, action);
+        assert.equal(store.getState(), 10);
+      });
+      it("should call .broadcast if the action is BroadcastToContent", () => {
+        sinon.stub(mm, "broadcast");
+        const action = ac.BroadcastToContent({ type: "FOO" });
+
+        store.dispatch(action);
+
+        assert.calledWith(mm.broadcast, action);
+      });
+      it("should call .sendToPreloaded if the action is AlsoToPreloaded", () => {
+        sinon.stub(mm, "sendToPreloaded");
+        const action = ac.AlsoToPreloaded({ type: "FOO" });
+
+        store.dispatch(action);
+
+        assert.calledWith(mm.sendToPreloaded, action);
+      });
+      it("should dispatch other actions normally", () => {
+        sinon.stub(mm, "send");
+        sinon.stub(mm, "broadcast");
+        sinon.stub(mm, "sendToPreloaded");
+
+        store.dispatch({ type: "ADD", data: 1 });
+
+        assert.equal(store.getState(), 1);
+        assert.notCalled(mm.send);
+        assert.notCalled(mm.broadcast);
+        assert.notCalled(mm.sendToPreloaded);
+      });
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/ActivityStreamPrefs.test.js b/browser/components/newtab/test/unit/lib/ActivityStreamPrefs.test.js
new file mode 100644
index 0000000000..bff1708ef7
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/ActivityStreamPrefs.test.js
@@ -0,0 +1,113 @@
+import { DefaultPrefs, Prefs } from "lib/ActivityStreamPrefs.sys.mjs";
+
+const TEST_PREF_CONFIG = new Map([
+  ["foo", { value: true }],
+  ["bar", { value: "BAR" }],
+  ["baz", { value: 1 }],
+  ["qux", { value: "foo", value_local_dev: "foofoo" }],
+]);
+
+describe("ActivityStreamPrefs", () => {
+  describe("Prefs", () => {
+    let p;
+    beforeEach(() => {
+      p = new Prefs();
+    });
+    it("should have get, set, and observe methods", () => {
+      assert.property(p, "get");
+      assert.property(p, "set");
+      assert.property(p, "observe");
+    });
+    describe("#observeBranch", () => {
+      let listener;
+      beforeEach(() => {
+        p._prefBranch = { addObserver: sinon.stub() };
+        listener = { onPrefChanged: sinon.stub() };
+        p.observeBranch(listener);
+      });
+      it("should add an observer", () => {
+        assert.calledOnce(p._prefBranch.addObserver);
+        assert.calledWith(p._prefBranch.addObserver, "");
+      });
+      it("should store the listener", () => {
+        assert.equal(p._branchObservers.size, 1);
+        assert.ok(p._branchObservers.has(listener));
+      });
+      it("should call listener's onPrefChanged", () => {
+        p._branchObservers.get(listener)();
+
+        assert.calledOnce(listener.onPrefChanged);
+      });
+    });
+    describe("#ignoreBranch", () => {
+      let listener;
+      beforeEach(() => {
+        p._prefBranch = {
+          addObserver: sinon.stub(),
+          removeObserver: sinon.stub(),
+        };
+        listener = {};
+        p.observeBranch(listener);
+      });
+      it("should remove the observer", () => {
+        p.ignoreBranch(listener);
+
+        assert.calledOnce(p._prefBranch.removeObserver);
+        assert.calledWith(
+          p._prefBranch.removeObserver,
+          p._prefBranch.addObserver.firstCall.args[0]
+        );
+      });
+      it("should remove the listener", () => {
+        assert.equal(p._branchObservers.size, 1);
+
+        p.ignoreBranch(listener);
+
+        assert.equal(p._branchObservers.size, 0);
+      });
+    });
+  });
+
+  describe("DefaultPrefs", () => {
+    describe("#init", () => {
+      let defaultPrefs;
+      let sandbox;
+      beforeEach(() => {
+        sandbox = sinon.createSandbox();
+        defaultPrefs = new DefaultPrefs(TEST_PREF_CONFIG);
+        sinon.stub(defaultPrefs, "set");
+      });
+      afterEach(() => {
+        sandbox.restore();
+      });
+      it("should initialize a boolean pref", () => {
+        defaultPrefs.init();
+        assert.calledWith(defaultPrefs.set, "foo", true);
+      });
+      it("should not initialize a pref if a default exists", () => {
+        defaultPrefs.prefs.set("foo", false);
+
+        defaultPrefs.init();
+
+        assert.neverCalledWith(defaultPrefs.set, "foo", true);
+      });
+      it("should initialize a string pref", () => {
+        defaultPrefs.init();
+        assert.calledWith(defaultPrefs.set, "bar", "BAR");
+      });
+      it("should initialize a integer pref", () => {
+        defaultPrefs.init();
+        assert.calledWith(defaultPrefs.set, "baz", 1);
+      });
+      it("should initialize a pref with value if Firefox is not a local build", () => {
+        defaultPrefs.init();
+        assert.calledWith(defaultPrefs.set, "qux", "foo");
+      });
+      it("should initialize a pref with value_local_dev if Firefox is a local build", () => {
+        sandbox.stub(global.AppConstants, "MOZILLA_OFFICIAL").value(false);
+        defaultPrefs.init();
+        assert.calledWith(defaultPrefs.set, "qux", "foofoo");
+      });
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/ActivityStreamStorage.test.js b/browser/components/newtab/test/unit/lib/ActivityStreamStorage.test.js
new file mode 100644
index 0000000000..0b8baef762
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/ActivityStreamStorage.test.js
@@ -0,0 +1,161 @@
+import { ActivityStreamStorage } from "lib/ActivityStreamStorage.sys.mjs";
+import { GlobalOverrider } from "test/unit/utils";
+
+let overrider = new GlobalOverrider();
+
+describe("ActivityStreamStorage", () => {
+  let sandbox;
+  let indexedDB;
+  let storage;
+  beforeEach(() => {
+    sandbox = sinon.createSandbox();
+    indexedDB = {
+      open: sandbox.stub().resolves({}),
+      deleteDatabase: sandbox.stub().resolves(),
+    };
+    overrider.set({ IndexedDB: indexedDB });
+    storage = new ActivityStreamStorage({
+      storeNames: ["storage_test"],
+      telemetry: { handleUndesiredEvent: sandbox.stub() },
+    });
+  });
+  afterEach(() => {
+    sandbox.restore();
+  });
+  it("should throw if required arguments not provided", () => {
+    assert.throws(() => new ActivityStreamStorage({ telemetry: true }));
+  });
+  describe(".db", () => {
+    it("should not throw an error when accessing db", async () => {
+      assert.ok(storage.db);
+    });
+
+    it("should delete and recreate the db if opening db fails", async () => {
+      const newDb = {};
+      indexedDB.open.onFirstCall().rejects(new Error("fake error"));
+      indexedDB.open.onSecondCall().resolves(newDb);
+
+      const db = await storage.db;
+      assert.calledOnce(indexedDB.deleteDatabase);
+      assert.calledTwice(indexedDB.open);
+      assert.equal(db, newDb);
+    });
+  });
+  describe("#getDbTable", () => {
+    let testStorage;
+    let storeStub;
+    beforeEach(() => {
+      storeStub = {
+        getAll: sandbox.stub().resolves(),
+        get: sandbox.stub().resolves(),
+        put: sandbox.stub().resolves(),
+      };
+      sandbox.stub(storage, "_getStore").resolves(storeStub);
+      testStorage = storage.getDbTable("storage_test");
+    });
+    it("should reverse key value parameters for put", async () => {
+      await testStorage.set("key", "value");
+
+      assert.calledOnce(storeStub.put);
+      assert.calledWith(storeStub.put, "value", "key");
+    });
+    it("should return the correct value for get", async () => {
+      storeStub.get.withArgs("foo").resolves("foo");
+
+      const result = await testStorage.get("foo");
+
+      assert.calledOnce(storeStub.get);
+      assert.equal(result, "foo");
+    });
+    it("should return the correct value for getAll", async () => {
+      storeStub.getAll.resolves(["bar"]);
+
+      const result = await testStorage.getAll();
+
+      assert.calledOnce(storeStub.getAll);
+      assert.deepEqual(result, ["bar"]);
+    });
+    it("should query the correct object store", async () => {
+      await testStorage.get();
+
+      assert.calledOnce(storage._getStore);
+      assert.calledWithExactly(storage._getStore, "storage_test");
+    });
+    it("should throw if table is not found", () => {
+      assert.throws(() => storage.getDbTable("undefined_store"));
+    });
+  });
+  it("should get the correct objectStore when calling _getStore", async () => {
+    const objectStoreStub = sandbox.stub();
+    indexedDB.open.resolves({ objectStore: objectStoreStub });
+
+    await storage._getStore("foo");
+
+    assert.calledOnce(objectStoreStub);
+    assert.calledWithExactly(objectStoreStub, "foo", "readwrite");
+  });
+  it("should create a db with the correct store name", async () => {
+    const dbStub = {
+      createObjectStore: sandbox.stub(),
+      objectStoreNames: { contains: sandbox.stub().returns(false) },
+    };
+    await storage.db;
+
+    // call the cb with a stub
+    indexedDB.open.args[0][2](dbStub);
+
+    assert.calledOnce(dbStub.createObjectStore);
+    assert.calledWithExactly(dbStub.createObjectStore, "storage_test");
+  });
+  it("should handle an array of object store names", async () => {
+    storage = new ActivityStreamStorage({
+      storeNames: ["store1", "store2"],
+      telemetry: {},
+    });
+    const dbStub = {
+      createObjectStore: sandbox.stub(),
+      objectStoreNames: { contains: sandbox.stub().returns(false) },
+    };
+    await storage.db;
+
+    // call the cb with a stub
+    indexedDB.open.args[0][2](dbStub);
+
+    assert.calledTwice(dbStub.createObjectStore);
+    assert.calledWith(dbStub.createObjectStore, "store1");
+    assert.calledWith(dbStub.createObjectStore, "store2");
+  });
+  it("should skip creating existing stores", async () => {
+    storage = new ActivityStreamStorage({
+      storeNames: ["store1", "store2"],
+      telemetry: {},
+    });
+    const dbStub = {
+      createObjectStore: sandbox.stub(),
+      objectStoreNames: { contains: sandbox.stub().returns(true) },
+    };
+    await storage.db;
+
+    // call the cb with a stub
+    indexedDB.open.args[0][2](dbStub);
+
+    assert.notCalled(dbStub.createObjectStore);
+  });
+  describe("#_requestWrapper", () => {
+    it("should return a successful result", async () => {
+      const result = await storage._requestWrapper(() =>
+        Promise.resolve("foo")
+      );
+
+      assert.equal(result, "foo");
+      assert.notCalled(storage.telemetry.handleUndesiredEvent);
+    });
+    it("should report failures", async () => {
+      try {
+        await storage._requestWrapper(() => Promise.reject(new Error()));
+      } catch (e) {
+        assert.calledOnce(storage.telemetry.handleUndesiredEvent);
+      }
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/DiscoveryStreamFeed.test.js b/browser/components/newtab/test/unit/lib/DiscoveryStreamFeed.test.js
new file mode 100644
index 0000000000..92e10facb3
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/DiscoveryStreamFeed.test.js
@@ -0,0 +1,3523 @@
+import {
+  actionCreators as ac,
+  actionTypes as at,
+  actionUtils as au,
+} from "common/Actions.sys.mjs";
+import { combineReducers, createStore } from "redux";
+import { GlobalOverrider } from "test/unit/utils";
+import { DiscoveryStreamFeed } from "lib/DiscoveryStreamFeed.sys.mjs";
+import { RecommendationProvider } from "lib/RecommendationProvider.sys.mjs";
+import { reducers } from "common/Reducers.sys.mjs";
+
+import { PersistentCache } from "lib/PersistentCache.sys.mjs";
+
+const CONFIG_PREF_NAME = "discoverystream.config";
+const ENDPOINTS_PREF_NAME = "discoverystream.endpoints";
+const DUMMY_ENDPOINT = "https://getpocket.cdn.mozilla.net/dummy";
+const SPOC_IMPRESSION_TRACKING_PREF = "discoverystream.spoc.impressions";
+const REC_IMPRESSION_TRACKING_PREF = "discoverystream.rec.impressions";
+const THIRTY_MINUTES = 30 * 60 * 1000;
+const ONE_WEEK = 7 * 24 * 60 * 60 * 1000; // 1 week
+
+const FAKE_UUID = "{foo-123-foo}";
+
+// eslint-disable-next-line max-statements
+describe("DiscoveryStreamFeed", () => {
+  let feed;
+  let feeds;
+  let recommendationProvider;
+  let sandbox;
+  let fetchStub;
+  let clock;
+  let fakeNewTabUtils;
+  let fakePktApi;
+  let globals;
+
+  const setPref = (name, value) => {
+    const action = {
+      type: at.PREF_CHANGED,
+      data: {
+        name,
+        value: typeof value === "object" ? JSON.stringify(value) : value,
+      },
+    };
+    feed.store.dispatch(action);
+    feed.onAction(action);
+  };
+
+  beforeEach(() => {
+    sandbox = sinon.createSandbox();
+
+    // Fetch
+    fetchStub = sandbox.stub(global, "fetch");
+
+    // Time
+    clock = sinon.useFakeTimers();
+
+    globals = new GlobalOverrider();
+    globals.set({
+      gUUIDGenerator: { generateUUID: () => FAKE_UUID },
+      PersistentCache,
+    });
+
+    sandbox
+      .stub(global.Services.prefs, "getBoolPref")
+      .withArgs("browser.newtabpage.activity-stream.discoverystream.enabled")
+      .returns(true);
+
+    recommendationProvider = new RecommendationProvider();
+    recommendationProvider.store = createStore(combineReducers(reducers), {});
+    feeds = {
+      "feeds.recommendationprovider": recommendationProvider,
+    };
+
+    // Feed
+    feed = new DiscoveryStreamFeed();
+    feed.store = createStore(combineReducers(reducers), {
+      Prefs: {
+        values: {
+          [CONFIG_PREF_NAME]: JSON.stringify({
+            enabled: false,
+          }),
+          [ENDPOINTS_PREF_NAME]: DUMMY_ENDPOINT,
+          "discoverystream.enabled": true,
+          "feeds.section.topstories": true,
+          "feeds.system.topstories": true,
+          "discoverystream.spocs.personalized": true,
+          "discoverystream.recs.personalized": true,
+          "system.showSponsored": false,
+        },
+      },
+    });
+    feed.store.feeds = {
+      get: name => feeds[name],
+    };
+    global.fetch.resetHistory();
+
+    sandbox.stub(feed, "_maybeUpdateCachedData").resolves();
+
+    globals.set("setTimeout", callback => {
+      callback();
+    });
+
+    fakeNewTabUtils = {
+      blockedLinks: {
+        links: [],
+        isBlocked: () => false,
+      },
+    };
+    globals.set("NewTabUtils", fakeNewTabUtils);
+
+    fakePktApi = {
+      isUserLoggedIn: () => false,
+      getRecentSavesCache: () => null,
+      getRecentSaves: () => null,
+    };
+    globals.set("pktApi", fakePktApi);
+  });
+
+  afterEach(() => {
+    clock.restore();
+    sandbox.restore();
+    globals.restore();
+  });
+
+  describe("#fetchFromEndpoint", () => {
+    beforeEach(() => {
+      feed._prefCache = {
+        config: {
+          api_key_pref: "",
+        },
+      };
+      fetchStub.resolves({
+        json: () => Promise.resolve("hi"),
+        ok: true,
+      });
+    });
+    it("should get a response", async () => {
+      const response = await feed.fetchFromEndpoint(DUMMY_ENDPOINT);
+
+      assert.equal(response, "hi");
+    });
+    it("should not send cookies", async () => {
+      await feed.fetchFromEndpoint(DUMMY_ENDPOINT);
+
+      assert.propertyVal(fetchStub.firstCall.args[1], "credentials", "omit");
+    });
+    it("should allow unexpected response", async () => {
+      fetchStub.resolves({ ok: false });
+
+      const response = await feed.fetchFromEndpoint(DUMMY_ENDPOINT);
+
+      assert.equal(response, null);
+    });
+    it("should disallow unexpected endpoints", async () => {
+      feed.store.getState = () => ({
+        Prefs: {
+          values: {
+            [ENDPOINTS_PREF_NAME]: "https://other.site",
+          },
+        },
+      });
+
+      const response = await feed.fetchFromEndpoint(DUMMY_ENDPOINT);
+
+      assert.equal(response, null);
+    });
+    it("should allow multiple endpoints", async () => {
+      feed.store.getState = () => ({
+        Prefs: {
+          values: {
+            [ENDPOINTS_PREF_NAME]: `https://other.site,${DUMMY_ENDPOINT}`,
+          },
+        },
+      });
+
+      const response = await feed.fetchFromEndpoint(DUMMY_ENDPOINT);
+
+      assert.equal(response, "hi");
+    });
+    it("should replace urls with $apiKey", async () => {
+      sandbox.stub(global.Services.prefs, "getCharPref").returns("replaced");
+
+      await feed.fetchFromEndpoint(
+        "https://getpocket.cdn.mozilla.net/dummy?consumer_key=$apiKey"
+      );
+
+      assert.calledWithMatch(
+        fetchStub,
+        "https://getpocket.cdn.mozilla.net/dummy?consumer_key=replaced",
+        { credentials: "omit" }
+      );
+    });
+    it("should replace locales with $locale", async () => {
+      feed.locale = "replaced";
+      await feed.fetchFromEndpoint(
+        "https://getpocket.cdn.mozilla.net/dummy?locale_lang=$locale"
+      );
+
+      assert.calledWithMatch(
+        fetchStub,
+        "https://getpocket.cdn.mozilla.net/dummy?locale_lang=replaced",
+        { credentials: "omit" }
+      );
+    });
+    it("should allow POST and with other options", async () => {
+      await feed.fetchFromEndpoint("https://getpocket.cdn.mozilla.net/dummy", {
+        method: "POST",
+        body: "{}",
+      });
+
+      assert.calledWithMatch(
+        fetchStub,
+        "https://getpocket.cdn.mozilla.net/dummy",
+        {
+          credentials: "omit",
+          method: "POST",
+          body: "{}",
+        }
+      );
+    });
+  });
+
+  describe("#setupPocketState", () => {
+    it("should setup logged in state and recent saves with cache", async () => {
+      fakePktApi.isUserLoggedIn = () => true;
+      fakePktApi.getRecentSavesCache = () => [1, 2, 3];
+      sandbox.spy(feed.store, "dispatch");
+      await feed.setupPocketState({});
+      assert.calledTwice(feed.store.dispatch);
+      assert.calledWith(
+        feed.store.dispatch.firstCall,
+        ac.OnlyToOneContent(
+          {
+            type: at.DISCOVERY_STREAM_POCKET_STATE_SET,
+            data: { isUserLoggedIn: true },
+          },
+          {}
+        )
+      );
+      assert.calledWith(
+        feed.store.dispatch.secondCall,
+        ac.OnlyToOneContent(
+          {
+            type: at.DISCOVERY_STREAM_RECENT_SAVES,
+            data: { recentSaves: [1, 2, 3] },
+          },
+          {}
+        )
+      );
+    });
+    it("should setup logged in state and recent saves without cache", async () => {
+      fakePktApi.isUserLoggedIn = () => true;
+      fakePktApi.getRecentSaves = ({ success }) => success([1, 2, 3]);
+      sandbox.spy(feed.store, "dispatch");
+      await feed.setupPocketState({});
+      assert.calledTwice(feed.store.dispatch);
+      assert.calledWith(
+        feed.store.dispatch.firstCall,
+        ac.OnlyToOneContent(
+          {
+            type: at.DISCOVERY_STREAM_POCKET_STATE_SET,
+            data: { isUserLoggedIn: true },
+          },
+          {}
+        )
+      );
+      assert.calledWith(
+        feed.store.dispatch.secondCall,
+        ac.OnlyToOneContent(
+          {
+            type: at.DISCOVERY_STREAM_RECENT_SAVES,
+            data: { recentSaves: [1, 2, 3] },
+          },
+          {}
+        )
+      );
+    });
+  });
+
+  describe("#getOrCreateImpressionId", () => {
+    it("should create impression id in constructor", async () => {
+      assert.equal(feed._impressionId, FAKE_UUID);
+    });
+    it("should create impression id if none exists", async () => {
+      sandbox.stub(global.Services.prefs, "getCharPref").returns("");
+      sandbox.stub(global.Services.prefs, "setCharPref").returns();
+
+      const result = feed.getOrCreateImpressionId();
+
+      assert.equal(result, FAKE_UUID);
+      assert.calledOnce(global.Services.prefs.setCharPref);
+    });
+    it("should use impression id if exists", async () => {
+      sandbox.stub(global.Services.prefs, "getCharPref").returns("from get");
+
+      const result = feed.getOrCreateImpressionId();
+
+      assert.equal(result, "from get");
+      assert.calledOnce(global.Services.prefs.getCharPref);
+    });
+  });
+
+  describe("#parseGridPositions", () => {
+    it("should return an equivalent array for an array of non negative integers", async () => {
+      assert.deepEqual(feed.parseGridPositions([0, 2, 3]), [0, 2, 3]);
+    });
+    it("should return undefined for an array containing negative integers", async () => {
+      assert.equal(feed.parseGridPositions([-2, 2, 3]), undefined);
+    });
+    it("should return undefined for an undefined input", async () => {
+      assert.equal(feed.parseGridPositions(undefined), undefined);
+    });
+  });
+
+  describe("#loadLayout", () => {
+    it("should use local basic layout with hardcoded_basic_layout being true", async () => {
+      feed.config.hardcoded_basic_layout = true;
+
+      await feed.loadLayout(feed.store.dispatch);
+
+      assert.equal(
+        feed.store.getState().DiscoveryStream.spocs.spocs_endpoint,
+        "https://spocs.getpocket.com/spocs"
+      );
+      const { layout } = feed.store.getState().DiscoveryStream;
+      assert.equal(layout[0].components[2].properties.items, 3);
+    });
+    it("should use 1 row layout if specified", async () => {
+      feed.store = createStore(combineReducers(reducers), {
+        Prefs: {
+          values: {
+            [CONFIG_PREF_NAME]: JSON.stringify({
+              enabled: true,
+            }),
+            [ENDPOINTS_PREF_NAME]: DUMMY_ENDPOINT,
+            "discoverystream.enabled": true,
+            "discoverystream.region-basic-layout": true,
+            "system.showSponsored": false,
+          },
+        },
+      });
+
+      await feed.loadLayout(feed.store.dispatch);
+
+      const { layout } = feed.store.getState().DiscoveryStream;
+      assert.equal(layout[0].components[2].properties.items, 3);
+    });
+    it("should use 7 row layout if specified", async () => {
+      feed.store = createStore(combineReducers(reducers), {
+        Prefs: {
+          values: {
+            [CONFIG_PREF_NAME]: JSON.stringify({
+              enabled: true,
+            }),
+            [ENDPOINTS_PREF_NAME]: DUMMY_ENDPOINT,
+            "discoverystream.enabled": true,
+            "discoverystream.region-basic-layout": false,
+            "system.showSponsored": false,
+          },
+        },
+      });
+
+      await feed.loadLayout(feed.store.dispatch);
+
+      const { layout } = feed.store.getState().DiscoveryStream;
+      assert.equal(layout[0].components[2].properties.items, 21);
+    });
+    it("should use new spocs endpoint if in the config", async () => {
+      feed.config.spocs_endpoint = "https://spocs.getpocket.com/spocs2";
+
+      await feed.loadLayout(feed.store.dispatch);
+
+      assert.equal(
+        feed.store.getState().DiscoveryStream.spocs.spocs_endpoint,
+        "https://spocs.getpocket.com/spocs2"
+      );
+    });
+    it("should use local basic layout with FF pref hardcoded_basic_layout", async () => {
+      feed.store = createStore(combineReducers(reducers), {
+        Prefs: {
+          values: {
+            [CONFIG_PREF_NAME]: JSON.stringify({
+              enabled: false,
+            }),
+            [ENDPOINTS_PREF_NAME]: DUMMY_ENDPOINT,
+            "discoverystream.enabled": true,
+            "discoverystream.hardcoded-basic-layout": true,
+            "system.showSponsored": false,
+          },
+        },
+      });
+
+      await feed.loadLayout(feed.store.dispatch);
+
+      assert.equal(
+        feed.store.getState().DiscoveryStream.spocs.spocs_endpoint,
+        "https://spocs.getpocket.com/spocs"
+      );
+      const { layout } = feed.store.getState().DiscoveryStream;
+      assert.equal(layout[0].components[2].properties.items, 3);
+    });
+    it("should use new spocs endpoint if in a FF pref", async () => {
+      feed.store = createStore(combineReducers(reducers), {
+        Prefs: {
+          values: {
+            [CONFIG_PREF_NAME]: JSON.stringify({
+              enabled: false,
+            }),
+            [ENDPOINTS_PREF_NAME]: DUMMY_ENDPOINT,
+            "discoverystream.enabled": true,
+            "discoverystream.spocs-endpoint":
+              "https://spocs.getpocket.com/spocs2",
+            "system.showSponsored": false,
+          },
+        },
+      });
+
+      await feed.loadLayout(feed.store.dispatch);
+
+      assert.equal(
+        feed.store.getState().DiscoveryStream.spocs.spocs_endpoint,
+        "https://spocs.getpocket.com/spocs2"
+      );
+    });
+    it("should return enough stories to fill a four card layout", async () => {
+      feed.store = createStore(combineReducers(reducers), {
+        Prefs: {
+          values: {
+            pocketConfig: { fourCardLayout: true },
+          },
+        },
+      });
+
+      await feed.loadLayout(feed.store.dispatch);
+
+      const { layout } = feed.store.getState().DiscoveryStream;
+      assert.equal(layout[0].components[2].properties.items, 24);
+    });
+    it("should create a layout with spoc and widget positions", async () => {
+      feed.store = createStore(combineReducers(reducers), {
+        Prefs: {
+          values: {
+            pocketConfig: {
+              spocPositions: "1, 2",
+              widgetPositions: "3, 4",
+            },
+          },
+        },
+      });
+
+      await feed.loadLayout(feed.store.dispatch);
+
+      const { layout } = feed.store.getState().DiscoveryStream;
+      assert.deepEqual(layout[0].components[2].spocs.positions, [
+        { index: 1 },
+        { index: 2 },
+      ]);
+      assert.deepEqual(layout[0].components[2].widgets.positions, [
+        { index: 3 },
+        { index: 4 },
+      ]);
+    });
+    it("should create a layout with spoc position data", async () => {
+      feed.store = createStore(combineReducers(reducers), {
+        Prefs: {
+          values: {
+            pocketConfig: {
+              spocAdTypes: "1230",
+              spocZoneIds: "4560, 7890",
+            },
+          },
+        },
+      });
+
+      await feed.loadLayout(feed.store.dispatch);
+
+      const { layout } = feed.store.getState().DiscoveryStream;
+      assert.deepEqual(layout[0].components[2].placement.ad_types, [1230]);
+      assert.deepEqual(
+        layout[0].components[2].placement.zone_ids,
+        [4560, 7890]
+      );
+    });
+    it("should create a layout with spoc topsite position data", async () => {
+      feed.store = createStore(combineReducers(reducers), {
+        Prefs: {
+          values: {
+            pocketConfig: {
+              spocTopsitesPlacementEnabled: true,
+              spocTopsitesAdTypes: "1230",
+              spocTopsitesZoneIds: "4560, 7890",
+            },
+          },
+        },
+      });
+
+      await feed.loadLayout(feed.store.dispatch);
+
+      const { layout } = feed.store.getState().DiscoveryStream;
+      assert.deepEqual(layout[0].components[0].placement.ad_types, [1230]);
+      assert.deepEqual(
+        layout[0].components[0].placement.zone_ids,
+        [4560, 7890]
+      );
+    });
+    it("should create a layout with proper spoc url with a site id", async () => {
+      feed.store = createStore(combineReducers(reducers), {
+        Prefs: {
+          values: {
+            pocketConfig: {
+              spocSiteId: "1234",
+            },
+          },
+        },
+      });
+
+      await feed.loadLayout(feed.store.dispatch);
+      const { spocs } = feed.store.getState().DiscoveryStream;
+      assert.deepEqual(
+        spocs.spocs_endpoint,
+        "https://spocs.getpocket.com/spocs?site=1234"
+      );
+    });
+  });
+
+  describe("#updatePlacements", () => {
+    it("should dispatch DISCOVERY_STREAM_SPOCS_PLACEMENTS", () => {
+      sandbox.spy(feed.store, "dispatch");
+      feed.store.getState = () => ({
+        Prefs: {
+          values: { showSponsored: true, "system.showSponsored": true },
+        },
+      });
+      const fakeComponents = {
+        components: [
+          { placement: { name: "first" }, spocs: {} },
+          { placement: { name: "second" }, spocs: {} },
+        ],
+      };
+      const fakeLayout = [fakeComponents];
+
+      feed.updatePlacements(feed.store.dispatch, fakeLayout);
+
+      assert.calledOnce(feed.store.dispatch);
+      assert.calledWith(feed.store.dispatch, {
+        type: "DISCOVERY_STREAM_SPOCS_PLACEMENTS",
+        data: { placements: [{ name: "first" }, { name: "second" }] },
+        meta: { isStartup: false },
+      });
+    });
+    it("should dispatch DISCOVERY_STREAM_SPOCS_PLACEMENTS with prefs array", () => {
+      sandbox.spy(feed.store, "dispatch");
+      feed.store.getState = () => ({
+        Prefs: {
+          values: {
+            showSponsored: true,
+            withPref: true,
+            "system.showSponsored": true,
+          },
+        },
+      });
+      const fakeComponents = {
+        components: [
+          { placement: { name: "withPref" }, spocs: { prefs: ["withPref"] } },
+          { placement: { name: "withoutPref1" }, spocs: {} },
+          {
+            placement: { name: "withoutPref2" },
+            spocs: { prefs: ["whatever"] },
+          },
+          { placement: { name: "withoutPref3" }, spocs: { prefs: [] } },
+        ],
+      };
+      const fakeLayout = [fakeComponents];
+
+      feed.updatePlacements(feed.store.dispatch, fakeLayout);
+
+      assert.calledOnce(feed.store.dispatch);
+      assert.calledWith(feed.store.dispatch, {
+        type: "DISCOVERY_STREAM_SPOCS_PLACEMENTS",
+        data: { placements: [{ name: "withPref" }, { name: "withoutPref1" }] },
+        meta: { isStartup: false },
+      });
+    });
+    it("should fire update placements from loadLayout", async () => {
+      sandbox.spy(feed, "updatePlacements");
+
+      await feed.loadLayout(feed.store.dispatch);
+
+      assert.calledOnce(feed.updatePlacements);
+    });
+  });
+
+  describe("#placementsForEach", () => {
+    it("should forEach through placements", () => {
+      feed.store.getState = () => ({
+        DiscoveryStream: {
+          spocs: {
+            placements: [{ name: "first" }, { name: "second" }],
+          },
+        },
+      });
+
+      let items = [];
+
+      feed.placementsForEach(item => items.push(item.name));
+
+      assert.deepEqual(items, ["first", "second"]);
+    });
+  });
+
+  describe("#loadComponentFeeds", () => {
+    let fakeCache;
+    let fakeDiscoveryStream;
+    beforeEach(() => {
+      fakeDiscoveryStream = {
+        Prefs: {},
+        DiscoveryStream: {
+          layout: [
+            { components: [{ feed: { url: "foo.com" } }] },
+            { components: [{}] },
+            {},
+          ],
+        },
+      };
+      fakeCache = {};
+      sandbox.stub(feed.store, "getState").returns(fakeDiscoveryStream);
+      sandbox.stub(feed.cache, "set").returns(Promise.resolve());
+    });
+
+    afterEach(() => {
+      sandbox.restore();
+    });
+
+    it("should not dispatch updates when layout is not defined", async () => {
+      fakeDiscoveryStream = {
+        DiscoveryStream: {},
+      };
+      feed.store.getState.returns(fakeDiscoveryStream);
+      sandbox.spy(feed.store, "dispatch");
+
+      await feed.loadComponentFeeds(feed.store.dispatch);
+
+      assert.notCalled(feed.store.dispatch);
+    });
+
+    it("should populate feeds cache", async () => {
+      fakeCache = {
+        feeds: { "foo.com": { lastUpdated: Date.now(), data: "data" } },
+      };
+      sandbox.stub(feed.cache, "get").returns(Promise.resolve(fakeCache));
+
+      await feed.loadComponentFeeds(feed.store.dispatch);
+
+      assert.calledWith(feed.cache.set, "feeds", {
+        "foo.com": { data: "data", lastUpdated: 0 },
+      });
+    });
+
+    it("should send feed update events with new feed data", async () => {
+      sandbox.stub(feed.cache, "get").returns(Promise.resolve(fakeCache));
+      sandbox.spy(feed.store, "dispatch");
+      feed._prefCache = {
+        config: {
+          api_key_pref: "",
+        },
+      };
+
+      await feed.loadComponentFeeds(feed.store.dispatch);
+
+      assert.calledWith(feed.store.dispatch.firstCall, {
+        type: at.DISCOVERY_STREAM_FEED_UPDATE,
+        data: { feed: { data: { status: "failed" } }, url: "foo.com" },
+        meta: { isStartup: false },
+      });
+      assert.calledWith(feed.store.dispatch.secondCall, {
+        type: at.DISCOVERY_STREAM_FEEDS_UPDATE,
+        meta: { isStartup: false },
+      });
+    });
+
+    it("should return number of promises equal to unique urls", async () => {
+      sandbox.stub(feed.cache, "get").returns(Promise.resolve(fakeCache));
+      sandbox.stub(global.Promise, "all").resolves();
+      fakeDiscoveryStream = {
+        DiscoveryStream: {
+          layout: [
+            {
+              components: [
+                { feed: { url: "foo.com" } },
+                { feed: { url: "bar.com" } },
+              ],
+            },
+            { components: [{ feed: { url: "foo.com" } }] },
+            {},
+            { components: [{ feed: { url: "baz.com" } }] },
+          ],
+        },
+      };
+      feed.store.getState.returns(fakeDiscoveryStream);
+
+      await feed.loadComponentFeeds(feed.store.dispatch);
+
+      assert.calledOnce(global.Promise.all);
+      const { args } = global.Promise.all.firstCall;
+      assert.equal(args[0].length, 3);
+    });
+  });
+
+  describe("#getComponentFeed", () => {
+    it("should fetch fresh feed data if cache is empty", async () => {
+      const fakeCache = {};
+      sandbox.stub(feed.cache, "get").returns(Promise.resolve(fakeCache));
+      sandbox.stub(feed, "rotate").callsFake(val => val);
+      sandbox
+        .stub(feed, "scoreItems")
+        .callsFake(val => ({ data: val, filtered: [], personalized: false }));
+      sandbox.stub(feed, "fetchFromEndpoint").resolves({
+        recommendations: "data",
+        settings: {
+          recsExpireTime: 1,
+        },
+      });
+
+      const feedResp = await feed.getComponentFeed("foo.com");
+
+      assert.equal(feedResp.data.recommendations, "data");
+    });
+    it("should fetch fresh feed data if cache is old", async () => {
+      const fakeCache = { feeds: { "foo.com": { lastUpdated: Date.now() } } };
+      sandbox.stub(feed.cache, "get").returns(Promise.resolve(fakeCache));
+      sandbox.stub(feed, "fetchFromEndpoint").resolves({
+        recommendations: "data",
+        settings: {
+          recsExpireTime: 1,
+        },
+      });
+      sandbox.stub(feed, "rotate").callsFake(val => val);
+      sandbox
+        .stub(feed, "scoreItems")
+        .callsFake(val => ({ data: val, filtered: [], personalized: false }));
+      clock.tick(THIRTY_MINUTES + 1);
+
+      const feedResp = await feed.getComponentFeed("foo.com");
+
+      assert.equal(feedResp.data.recommendations, "data");
+    });
+    it("should return feed data from cache if it is fresh", async () => {
+      const fakeCache = {
+        feeds: { "foo.com": { lastUpdated: Date.now(), data: "data" } },
+      };
+      sandbox.stub(feed.cache, "get").resolves(fakeCache);
+      sandbox.stub(feed, "fetchFromEndpoint").resolves("old data");
+      clock.tick(THIRTY_MINUTES - 1);
+
+      const feedResp = await feed.getComponentFeed("foo.com");
+
+      assert.equal(feedResp.data, "data");
+    });
+    it("should return null if no response was received", async () => {
+      sandbox.stub(feed, "fetchFromEndpoint").resolves(null);
+
+      const feedResp = await feed.getComponentFeed("foo.com");
+
+      assert.deepEqual(feedResp, { data: { status: "failed" } });
+    });
+  });
+
+  describe("#loadSpocs", () => {
+    beforeEach(() => {
+      feed._prefCache = {
+        config: {
+          api_key_pref: "",
+        },
+      };
+
+      sandbox.stub(feed, "getPlacements").returns([{ name: "spocs" }]);
+      Object.defineProperty(feed, "showSpocs", { get: () => true });
+    });
+    it("should not fetch or update cache if no spocs endpoint is defined", async () => {
+      feed.store.dispatch(
+        ac.BroadcastToContent({
+          type: at.DISCOVERY_STREAM_SPOCS_ENDPOINT,
+          data: "",
+        })
+      );
+
+      sandbox.spy(feed.cache, "set");
+
+      await feed.loadSpocs(feed.store.dispatch);
+
+      assert.notCalled(global.fetch);
+      assert.calledWith(feed.cache.set, "spocs", { lastUpdated: 0, spocs: {} });
+    });
+    it("should fetch fresh spocs data if cache is empty", async () => {
+      sandbox.stub(feed.cache, "get").returns(Promise.resolve());
+      sandbox.stub(feed, "fetchFromEndpoint").resolves({ placement: "data" });
+      sandbox.stub(feed.cache, "set").returns(Promise.resolve());
+
+      await feed.loadSpocs(feed.store.dispatch);
+
+      assert.calledWith(feed.cache.set, "spocs", {
+        spocs: { placement: "data" },
+        lastUpdated: 0,
+      });
+      assert.equal(
+        feed.store.getState().DiscoveryStream.spocs.data.placement,
+        "data"
+      );
+    });
+    it("should fetch fresh data if cache is old", async () => {
+      const cachedSpoc = {
+        spocs: { placement: "old" },
+        lastUpdated: Date.now(),
+      };
+      const cachedData = { spocs: cachedSpoc };
+      sandbox.stub(feed.cache, "get").returns(Promise.resolve(cachedData));
+      sandbox.stub(feed, "fetchFromEndpoint").resolves({ placement: "new" });
+      sandbox.stub(feed.cache, "set").returns(Promise.resolve());
+      clock.tick(THIRTY_MINUTES + 1);
+
+      await feed.loadSpocs(feed.store.dispatch);
+
+      assert.equal(
+        feed.store.getState().DiscoveryStream.spocs.data.placement,
+        "new"
+      );
+    });
+    it("should return spoc data from cache if it is fresh", async () => {
+      const cachedSpoc = {
+        spocs: { placement: "old" },
+        lastUpdated: Date.now(),
+      };
+      const cachedData = { spocs: cachedSpoc };
+      sandbox.stub(feed.cache, "get").returns(Promise.resolve(cachedData));
+      sandbox.stub(feed, "fetchFromEndpoint").resolves({ placement: "new" });
+      sandbox.stub(feed.cache, "set").returns(Promise.resolve());
+      clock.tick(THIRTY_MINUTES - 1);
+
+      await feed.loadSpocs(feed.store.dispatch);
+
+      assert.equal(
+        feed.store.getState().DiscoveryStream.spocs.data.placement,
+        "old"
+      );
+    });
+    it("should properly transform spocs using placements", async () => {
+      sandbox.stub(feed.cache, "get").returns(Promise.resolve());
+      sandbox.stub(feed, "fetchFromEndpoint").resolves({
+        spocs: { items: [{ id: "data" }] },
+      });
+      sandbox.stub(feed.cache, "set").returns(Promise.resolve());
+
+      await feed.loadSpocs(feed.store.dispatch);
+
+      assert.calledWith(feed.cache.set, "spocs", {
+        spocs: {
+          spocs: {
+            personalized: false,
+            context: "",
+            title: "",
+            sponsor: "",
+            sponsored_by_override: undefined,
+            items: [{ id: "data", score: 1 }],
+          },
+        },
+        lastUpdated: 0,
+      });
+
+      assert.deepEqual(
+        feed.store.getState().DiscoveryStream.spocs.data.spocs.items[0],
+        { id: "data", score: 1 }
+      );
+    });
+    it("should normalizeSpocsItems for older spoc data", async () => {
+      sandbox.stub(feed.cache, "get").returns(Promise.resolve());
+      sandbox
+        .stub(feed, "fetchFromEndpoint")
+        .resolves({ spocs: [{ id: "data" }] });
+      sandbox.stub(feed.cache, "set").returns(Promise.resolve());
+
+      await feed.loadSpocs(feed.store.dispatch);
+
+      assert.deepEqual(
+        feed.store.getState().DiscoveryStream.spocs.data.spocs.items[0],
+        { id: "data", score: 1 }
+      );
+    });
+    it("should dispatch DISCOVERY_STREAM_PERSONALIZATION_OVERRIDE with feature_flags", async () => {
+      sandbox.stub(feed.cache, "get").returns(Promise.resolve());
+      sandbox.spy(feed.store, "dispatch");
+      sandbox
+        .stub(feed, "fetchFromEndpoint")
+        .resolves({ settings: { feature_flags: {} }, spocs: [{ id: "data" }] });
+      sandbox.stub(feed.cache, "set").returns(Promise.resolve());
+
+      await feed.loadSpocs(feed.store.dispatch);
+
+      assert.calledWith(
+        feed.store.dispatch,
+        ac.OnlyToMain({
+          type: at.DISCOVERY_STREAM_PERSONALIZATION_OVERRIDE,
+          data: {
+            override: true,
+          },
+        })
+      );
+    });
+    it("should return expected data if normalizeSpocsItems returns no spoc data", async () => {
+      // We don't need this for just this test, we are setting placements
+      // manually.
+      feed.getPlacements.restore();
+      Object.defineProperty(feed, "showSponsoredStories", {
+        get: () => true,
+      });
+
+      sandbox.stub(feed.cache, "get").returns(Promise.resolve());
+      sandbox
+        .stub(feed, "fetchFromEndpoint")
+        .resolves({ placement1: [{ id: "data" }], placement2: [] });
+      sandbox.stub(feed.cache, "set").returns(Promise.resolve());
+
+      const fakeComponents = {
+        components: [
+          { placement: { name: "placement1" }, spocs: {} },
+          { placement: { name: "placement2" }, spocs: {} },
+        ],
+      };
+      feed.updatePlacements(feed.store.dispatch, [fakeComponents]);
+
+      await feed.loadSpocs(feed.store.dispatch);
+
+      assert.deepEqual(feed.store.getState().DiscoveryStream.spocs.data, {
+        placement1: {
+          personalized: false,
+          title: "",
+          context: "",
+          sponsor: "",
+          sponsored_by_override: undefined,
+          items: [{ id: "data", score: 1 }],
+        },
+        placement2: {
+          title: "",
+          context: "",
+          items: [],
+        },
+      });
+    });
+    it("should use title and context on spoc data", async () => {
+      // We don't need this for just this test, we are setting placements
+      // manually.
+      feed.getPlacements.restore();
+      Object.defineProperty(feed, "showSponsoredStories", {
+        get: () => true,
+      });
+      sandbox.stub(feed.cache, "get").returns(Promise.resolve());
+      sandbox.stub(feed, "fetchFromEndpoint").resolves({
+        placement1: {
+          title: "title",
+          context: "context",
+          sponsor: "",
+          sponsored_by_override: undefined,
+          items: [{ id: "data" }],
+        },
+      });
+      sandbox.stub(feed.cache, "set").returns(Promise.resolve());
+
+      const fakeComponents = {
+        components: [{ placement: { name: "placement1" }, spocs: {} }],
+      };
+      feed.updatePlacements(feed.store.dispatch, [fakeComponents]);
+
+      await feed.loadSpocs(feed.store.dispatch);
+
+      assert.deepEqual(feed.store.getState().DiscoveryStream.spocs.data, {
+        placement1: {
+          personalized: false,
+          title: "title",
+          context: "context",
+          sponsor: "",
+          sponsored_by_override: undefined,
+          items: [{ id: "data", score: 1 }],
+        },
+      });
+    });
+    describe("test SOV behaviour", () => {
+      beforeEach(() => {
+        globals.set("NimbusFeatures", {
+          pocketNewtab: {
+            getVariable: sandbox.stub(),
+          },
+        });
+        global.NimbusFeatures.pocketNewtab.getVariable
+          .withArgs("topSitesContileSovEnabled")
+          .returns(true);
+        // We don't need this for just this test, we are setting placements
+        // manually.
+        feed.getPlacements.restore();
+        Object.defineProperty(feed, "showSponsoredStories", {
+          get: () => true,
+        });
+        const fakeComponents = {
+          components: [
+            { placement: { name: "sponsored-topsites" }, spocs: {} },
+            { placement: { name: "spocs" }, spocs: {} },
+          ],
+        };
+        feed.updatePlacements(feed.store.dispatch, [fakeComponents]);
+        sandbox.stub(feed.cache, "get").returns(Promise.resolve());
+        sandbox.stub(feed, "fetchFromEndpoint").resolves({
+          spocs: [{ id: "spoc1" }],
+          "sponsored-topsites": [{ id: "topsite1" }],
+        });
+      });
+      it("should use topsites placement by default if there is no SOV", async () => {
+        await feed.loadSpocs(feed.store.dispatch);
+
+        assert.equal(
+          feed.fetchFromEndpoint.firstCall.args[1].body,
+          JSON.stringify({
+            pocket_id: "{foo-123-foo}",
+            version: 2,
+            placements: [
+              {
+                name: "sponsored-topsites",
+              },
+              {
+                name: "spocs",
+              },
+            ],
+          })
+        );
+      });
+      it("should use cache if cache is available and SOV is not ready", async () => {
+        const cache = {
+          sov: [{ assignedPartner: "amp" }],
+        };
+        feed.cache.get.resolves(cache);
+        await feed.loadSpocs(feed.store.dispatch);
+
+        assert.equal(
+          feed.fetchFromEndpoint.firstCall.args[1].body,
+          JSON.stringify({
+            pocket_id: "{foo-123-foo}",
+            version: 2,
+            placements: [
+              {
+                name: "spocs",
+              },
+            ],
+          })
+        );
+      });
+      it("should properly set placements", async () => {
+        sandbox.spy(feed.cache, "set");
+
+        // Testing only 1 placement type.
+        feed.store.dispatch(
+          ac.OnlyToMain({
+            type: at.SOV_UPDATED,
+            data: {
+              ready: true,
+              positions: [
+                {
+                  position: 1,
+                  assignedPartner: "amp",
+                },
+                {
+                  position: 2,
+                  assignedPartner: "amp",
+                },
+              ],
+            },
+          })
+        );
+
+        await feed.loadSpocs(feed.store.dispatch);
+
+        const firstCall = feed.cache.set.getCall(0);
+        assert.deepEqual(firstCall.args[0], "sov");
+        assert.deepEqual(firstCall.args[1], [
+          {
+            position: 1,
+            assignedPartner: "amp",
+          },
+          {
+            position: 2,
+            assignedPartner: "amp",
+          },
+        ]);
+        assert.equal(
+          feed.fetchFromEndpoint.firstCall.args[1].body,
+          JSON.stringify({
+            pocket_id: "{foo-123-foo}",
+            version: 2,
+            placements: [
+              {
+                name: "spocs",
+              },
+            ],
+          })
+        );
+
+        // Testing 2 placement types.
+        feed.store.dispatch(
+          ac.OnlyToMain({
+            type: at.SOV_UPDATED,
+            data: {
+              ready: true,
+              positions: [
+                {
+                  position: 1,
+                  assignedPartner: "amp",
+                },
+                {
+                  position: 2,
+                  assignedPartner: "moz-sales",
+                },
+              ],
+            },
+          })
+        );
+
+        await feed.loadSpocs(feed.store.dispatch);
+
+        const secondCall = feed.cache.set.getCall(2);
+        assert.deepEqual(secondCall.args[0], "sov");
+        assert.deepEqual(secondCall.args[1], [
+          {
+            position: 1,
+            assignedPartner: "amp",
+          },
+          {
+            position: 2,
+            assignedPartner: "moz-sales",
+          },
+        ]);
+        assert.equal(
+          feed.fetchFromEndpoint.secondCall.args[1].body,
+          JSON.stringify({
+            pocket_id: "{foo-123-foo}",
+            version: 2,
+            placements: [
+              {
+                name: "sponsored-topsites",
+              },
+              {
+                name: "spocs",
+              },
+            ],
+          })
+        );
+      });
+    });
+  });
+
+  describe("#normalizeSpocsItems", () => {
+    it("should return correct data if new data passed in", async () => {
+      const spocs = {
+        title: "title",
+        context: "context",
+        sponsor: "sponsor",
+        sponsored_by_override: "override",
+        items: [{ id: "id" }],
+      };
+      const result = feed.normalizeSpocsItems(spocs);
+      assert.deepEqual(result, spocs);
+    });
+    it("should return normalized data if new data passed in without title or context", async () => {
+      const spocs = {
+        items: [{ id: "id" }],
+      };
+      const result = feed.normalizeSpocsItems(spocs);
+      assert.deepEqual(result, {
+        title: "",
+        context: "",
+        sponsor: "",
+        sponsored_by_override: undefined,
+        items: [{ id: "id" }],
+      });
+    });
+    it("should return normalized data if old data passed in", async () => {
+      const spocs = [{ id: "id" }];
+      const result = feed.normalizeSpocsItems(spocs);
+      assert.deepEqual(result, {
+        title: "",
+        context: "",
+        sponsor: "",
+        sponsored_by_override: undefined,
+        items: [{ id: "id" }],
+      });
+    });
+  });
+
+  describe("#showSpocs", () => {
+    it("should return true from showSpocs if showSponsoredStories is false", async () => {
+      Object.defineProperty(feed, "showSponsoredStories", {
+        get: () => false,
+      });
+      Object.defineProperty(feed, "showSponsoredTopsites", {
+        get: () => true,
+      });
+      assert.isTrue(feed.showSpocs);
+    });
+    it("should return true from showSpocs if showSponsoredTopsites is false", async () => {
+      Object.defineProperty(feed, "showSponsoredStories", {
+        get: () => true,
+      });
+      Object.defineProperty(feed, "showSponsoredTopsites", {
+        get: () => false,
+      });
+      assert.isTrue(feed.showSpocs);
+    });
+    it("should return true from showSpocs if both are true", async () => {
+      Object.defineProperty(feed, "showSponsoredStories", {
+        get: () => true,
+      });
+      Object.defineProperty(feed, "showSponsoredTopsites", {
+        get: () => true,
+      });
+      assert.isTrue(feed.showSpocs);
+    });
+    it("should return false from showSpocs if both are false", async () => {
+      Object.defineProperty(feed, "showSponsoredStories", {
+        get: () => false,
+      });
+      Object.defineProperty(feed, "showSponsoredTopsites", {
+        get: () => false,
+      });
+      assert.isFalse(feed.showSpocs);
+    });
+  });
+
+  describe("#showSponsoredStories", () => {
+    it("should return false from showSponsoredStories if user pref showSponsored is false", async () => {
+      feed.store.getState = () => ({
+        Prefs: {
+          values: { showSponsored: false, "system.showSponsored": true },
+        },
+      });
+
+      assert.isFalse(feed.showSponsoredStories);
+    });
+    it("should return false from showSponsoredStories if DiscoveryStream pref system.showSponsored is false", async () => {
+      feed.store.getState = () => ({
+        Prefs: {
+          values: { showSponsored: true, "system.showSponsored": false },
+        },
+      });
+
+      assert.isFalse(feed.showSponsoredStories);
+    });
+    it("should return true from showSponsoredStories if both prefs are true", async () => {
+      feed.store.getState = () => ({
+        Prefs: {
+          values: { showSponsored: true, "system.showSponsored": true },
+        },
+      });
+
+      assert.isTrue(feed.showSponsoredStories);
+    });
+  });
+
+  describe("#showSponsoredTopsites", () => {
+    it("should return false from showSponsoredTopsites if user pref showSponsoredTopSites is false", async () => {
+      feed.store.getState = () => ({
+        Prefs: { values: { showSponsoredTopSites: false } },
+        DiscoveryStream: {
+          spocs: {
+            placements: [{ name: "sponsored-topsites" }],
+          },
+        },
+      });
+      assert.isFalse(feed.showSponsoredTopsites);
+    });
+    it("should return true from showSponsoredTopsites if user pref showSponsoredTopSites is true", async () => {
+      feed.store.getState = () => ({
+        Prefs: { values: { showSponsoredTopSites: true } },
+        DiscoveryStream: {
+          spocs: {
+            placements: [{ name: "sponsored-topsites" }],
+          },
+        },
+      });
+      assert.isTrue(feed.showSponsoredTopsites);
+    });
+  });
+
+  describe("#showStories", () => {
+    it("should return false from showStories if user pref is false", async () => {
+      feed.store.getState = () => ({
+        Prefs: {
+          values: {
+            "feeds.section.topstories": false,
+            "feeds.system.topstories": true,
+          },
+        },
+      });
+      assert.isFalse(feed.showStories);
+    });
+    it("should return false from showStories if system pref is false", async () => {
+      feed.store.getState = () => ({
+        Prefs: {
+          values: {
+            "feeds.section.topstories": true,
+            "feeds.system.topstories": false,
+          },
+        },
+      });
+      assert.isFalse(feed.showStories);
+    });
+    it("should return true from showStories if both prefs are true", async () => {
+      feed.store.getState = () => ({
+        Prefs: {
+          values: {
+            "feeds.section.topstories": true,
+            "feeds.system.topstories": true,
+          },
+        },
+      });
+      assert.isTrue(feed.showStories);
+    });
+  });
+
+  describe("#showTopsites", () => {
+    it("should return false from showTopsites if user pref is false", async () => {
+      feed.store.getState = () => ({
+        Prefs: {
+          values: {
+            "feeds.topsites": false,
+            "feeds.system.topsites": true,
+          },
+        },
+      });
+      assert.isFalse(feed.showTopsites);
+    });
+    it("should return false from showTopsites if system pref is false", async () => {
+      feed.store.getState = () => ({
+        Prefs: {
+          values: {
+            "feeds.topsites": true,
+            "feeds.system.topsites": false,
+          },
+        },
+      });
+      assert.isFalse(feed.showTopsites);
+    });
+    it("should return true from showTopsites if both prefs are true", async () => {
+      feed.store.getState = () => ({
+        Prefs: {
+          values: {
+            "feeds.topsites": true,
+            "feeds.system.topsites": true,
+          },
+        },
+      });
+      assert.isTrue(feed.showTopsites);
+    });
+  });
+
+  describe("#clearSpocs", () => {
+    let defaultState;
+    let DiscoveryStream;
+    let Prefs;
+    beforeEach(() => {
+      DiscoveryStream = {
+        layout: [],
+        spocs: {
+          placements: [{ name: "sponsored-topsites" }],
+        },
+      };
+      Prefs = {
+        values: {
+          "feeds.section.topstories": true,
+          "feeds.system.topstories": true,
+          "feeds.topsites": true,
+          "feeds.system.topsites": true,
+          showSponsoredTopSites: true,
+          showSponsored: true,
+          "system.showSponsored": true,
+        },
+      };
+      defaultState = {
+        DiscoveryStream,
+        Prefs,
+      };
+      feed.store.getState = () => defaultState;
+    });
+    it("should not fail with no endpoint", async () => {
+      sandbox.stub(feed.store, "getState").returns({
+        Prefs: {
+          values: { PREF_SPOCS_CLEAR_ENDPOINT: null },
+        },
+      });
+      sandbox.stub(feed, "fetchFromEndpoint").resolves(null);
+
+      await feed.clearSpocs();
+
+      assert.notCalled(feed.fetchFromEndpoint);
+    });
+    it("should call DELETE with endpoint", async () => {
+      sandbox.stub(feed.store, "getState").returns({
+        Prefs: {
+          values: {
+            "discoverystream.endpointSpocsClear": "https://spocs/user",
+          },
+        },
+      });
+      sandbox.stub(feed, "fetchFromEndpoint").resolves(null);
+      feed._impressionId = "1234";
+
+      await feed.clearSpocs();
+
+      assert.equal(
+        feed.fetchFromEndpoint.firstCall.args[0],
+        "https://spocs/user"
+      );
+      assert.equal(feed.fetchFromEndpoint.firstCall.args[1].method, "DELETE");
+      assert.equal(
+        feed.fetchFromEndpoint.firstCall.args[1].body,
+        '{"pocket_id":"1234"}'
+      );
+    });
+    it("should properly call clearSpocs when sponsored content is changed", async () => {
+      sandbox.stub(feed, "clearSpocs").returns(Promise.resolve());
+      // sandbox.stub(feed, "updatePlacements").returns();
+      sandbox.stub(feed, "loadSpocs").returns();
+
+      await feed.onAction({
+        type: at.PREF_CHANGED,
+        data: { name: "showSponsored" },
+      });
+
+      assert.notCalled(feed.clearSpocs);
+
+      Prefs.values.showSponsoredTopSites = false;
+      Prefs.values.showSponsored = false;
+
+      await feed.onAction({
+        type: at.PREF_CHANGED,
+        data: { name: "showSponsored" },
+      });
+
+      assert.calledOnce(feed.clearSpocs);
+    });
+    it("should call clearSpocs when top stories and top sites is turned off", async () => {
+      sandbox.stub(feed, "clearSpocs").returns(Promise.resolve());
+      Prefs.values["feeds.section.topstories"] = false;
+      Prefs.values["feeds.topsites"] = false;
+
+      await feed.onAction({
+        type: at.PREF_CHANGED,
+        data: { name: "feeds.section.topstories" },
+      });
+
+      assert.calledOnce(feed.clearSpocs);
+
+      await feed.onAction({
+        type: at.PREF_CHANGED,
+        data: { name: "feeds.topsites" },
+      });
+
+      assert.calledTwice(feed.clearSpocs);
+    });
+  });
+
+  describe("#rotate", () => {
+    it("should move seen first story to the back of the response", () => {
+      const recsExpireTime = 5600;
+      const feedResponse = {
+        recommendations: [
+          {
+            id: "first",
+          },
+          {
+            id: "second",
+          },
+          {
+            id: "third",
+          },
+          {
+            id: "fourth",
+          },
+        ],
+        settings: {
+          recsExpireTime,
+        },
+      };
+      const fakeImpressions = {
+        first: Date.now() - recsExpireTime * 1000,
+        third: Date.now(),
+      };
+      sandbox.stub(feed, "readDataPref").returns(fakeImpressions);
+
+      const result = feed.rotate(
+        feedResponse.recommendations,
+        feedResponse.settings.recsExpireTime
+      );
+
+      assert.equal(result[3].id, "first");
+    });
+  });
+
+  describe("#reset", () => {
+    it("should fire all reset based functions", async () => {
+      sandbox.stub(global.Services.obs, "removeObserver").returns();
+
+      sandbox.stub(feed, "resetDataPrefs").returns();
+      sandbox.stub(feed, "resetCache").returns(Promise.resolve());
+      sandbox.stub(feed, "resetState").returns();
+
+      feed.loaded = true;
+
+      await feed.reset();
+
+      assert.calledOnce(feed.resetDataPrefs);
+      assert.calledOnce(feed.resetCache);
+      assert.calledOnce(feed.resetState);
+    });
+  });
+
+  describe("#resetCache", () => {
+    it("should set .feeds .spocs and .sov to {}", async () => {
+      sandbox.stub(feed.cache, "set").returns(Promise.resolve());
+
+      await feed.resetCache();
+
+      assert.callCount(feed.cache.set, 3);
+      const firstCall = feed.cache.set.getCall(0);
+      const secondCall = feed.cache.set.getCall(1);
+      const thirdCall = feed.cache.set.getCall(2);
+      assert.deepEqual(firstCall.args, ["feeds", {}]);
+      assert.deepEqual(secondCall.args, ["spocs", {}]);
+      assert.deepEqual(thirdCall.args, ["sov", {}]);
+    });
+  });
+
+  describe("#scoreItems", () => {
+    it("should return initial data if spocs are empty", async () => {
+      const { data: result } = await feed.scoreItems([]);
+
+      assert.equal(result.length, 0);
+    });
+
+    it("should sort based on item_score", async () => {
+      const { data: result } = await feed.scoreItems([
+        { id: 2, flight_id: 2, item_score: 0.8 },
+        { id: 4, flight_id: 4, item_score: 0.5 },
+        { id: 3, flight_id: 3, item_score: 0.7 },
+        { id: 1, flight_id: 1, item_score: 0.9 },
+      ]);
+
+      assert.deepEqual(result, [
+        { id: 1, flight_id: 1, item_score: 0.9, score: 0.9 },
+        { id: 2, flight_id: 2, item_score: 0.8, score: 0.8 },
+        { id: 3, flight_id: 3, item_score: 0.7, score: 0.7 },
+        { id: 4, flight_id: 4, item_score: 0.5, score: 0.5 },
+      ]);
+    });
+
+    it("should sort based on priority", async () => {
+      const { data: result } = await feed.scoreItems([
+        { id: 6, flight_id: 6, priority: 2, item_score: 0.7 },
+        { id: 2, flight_id: 3, priority: 1, item_score: 0.2 },
+        { id: 4, flight_id: 4, item_score: 0.6 },
+        { id: 5, flight_id: 5, priority: 2, item_score: 0.8 },
+        { id: 3, flight_id: 3, item_score: 0.8 },
+        { id: 1, flight_id: 1, priority: 1, item_score: 0.3 },
+      ]);
+
+      assert.deepEqual(result, [
+        {
+          id: 1,
+          flight_id: 1,
+          priority: 1,
+          score: 0.3,
+          item_score: 0.3,
+        },
+        {
+          id: 2,
+          flight_id: 3,
+          priority: 1,
+          score: 0.2,
+          item_score: 0.2,
+        },
+        {
+          id: 5,
+          flight_id: 5,
+          priority: 2,
+          score: 0.8,
+          item_score: 0.8,
+        },
+        {
+          id: 6,
+          flight_id: 6,
+          priority: 2,
+          score: 0.7,
+          item_score: 0.7,
+        },
+        { id: 3, flight_id: 3, item_score: 0.8, score: 0.8 },
+        { id: 4, flight_id: 4, item_score: 0.6, score: 0.6 },
+      ]);
+    });
+
+    it("should add a score prop to spocs", async () => {
+      const { data: result } = await feed.scoreItems([
+        { flight_id: 1, item_score: 0.9 },
+      ]);
+
+      assert.equal(result[0].score, 0.9);
+    });
+  });
+
+  describe("#filterBlocked", () => {
+    it("should return initial data if spocs are empty", () => {
+      const { data: result } = feed.filterBlocked([]);
+
+      assert.equal(result.length, 0);
+    });
+    it("should return initial data if links are not blocked", () => {
+      const { data: result } = feed.filterBlocked([
+        { url: "https://foo.com" },
+        { url: "test.com" },
+      ]);
+      assert.equal(result.length, 2);
+    });
+    it("should return initial recommendations data if links are not blocked", () => {
+      const { data: result } = feed.filterBlocked([
+        { url: "https://foo.com" },
+        { url: "test.com" },
+      ]);
+      assert.equal(result.length, 2);
+    });
+    it("filterRecommendations based on blockedlist by passing feed data", () => {
+      fakeNewTabUtils.blockedLinks.links = [{ url: "https://foo.com" }];
+      fakeNewTabUtils.blockedLinks.isBlocked = site =>
+        fakeNewTabUtils.blockedLinks.links[0].url === site.url;
+
+      const result = feed.filterRecommendations({
+        lastUpdated: 4,
+        data: {
+          recommendations: [{ url: "https://foo.com" }, { url: "test.com" }],
+        },
+      });
+
+      assert.equal(result.lastUpdated, 4);
+      assert.lengthOf(result.data.recommendations, 1);
+      assert.equal(result.data.recommendations[0].url, "test.com");
+      assert.notInclude(
+        result.data.recommendations,
+        fakeNewTabUtils.blockedLinks.links[0]
+      );
+    });
+  });
+
+  describe("#frequencyCapSpocs", () => {
+    it("should return filtered out spocs based on frequency caps", () => {
+      const fakeSpocs = [
+        {
+          id: 1,
+          flight_id: "seen",
+          caps: {
+            lifetime: 3,
+            flight: {
+              count: 1,
+              period: 1,
+            },
+          },
+        },
+        {
+          id: 2,
+          flight_id: "not-seen",
+          caps: {
+            lifetime: 3,
+            flight: {
+              count: 1,
+              period: 1,
+            },
+          },
+        },
+      ];
+      const fakeImpressions = {
+        seen: [Date.now() - 1],
+      };
+      sandbox.stub(feed, "readDataPref").returns(fakeImpressions);
+
+      const { data: result, filtered } = feed.frequencyCapSpocs(fakeSpocs);
+
+      assert.equal(result.length, 1);
+      assert.equal(result[0].flight_id, "not-seen");
+      assert.deepEqual(filtered, [fakeSpocs[0]]);
+    });
+    it("should return simple structure and do nothing with no spocs", () => {
+      const { data: result, filtered } = feed.frequencyCapSpocs([]);
+
+      assert.equal(result.length, 0);
+      assert.equal(filtered.length, 0);
+    });
+  });
+
+  describe("#migrateFlightId", () => {
+    it("should migrate campaign to flight if no flight exists", () => {
+      const fakeSpocs = [
+        {
+          id: 1,
+          campaign_id: "campaign",
+          caps: {
+            lifetime: 3,
+            campaign: {
+              count: 1,
+              period: 1,
+            },
+          },
+        },
+      ];
+      const { data: result } = feed.migrateFlightId(fakeSpocs);
+
+      assert.deepEqual(result[0], {
+        id: 1,
+        flight_id: "campaign",
+        campaign_id: "campaign",
+        caps: {
+          lifetime: 3,
+          flight: {
+            count: 1,
+            period: 1,
+          },
+          campaign: {
+            count: 1,
+            period: 1,
+          },
+        },
+      });
+    });
+    it("should not migrate campaign to flight if caps or id don't exist", () => {
+      const fakeSpocs = [{ id: 1 }];
+      const { data: result } = feed.migrateFlightId(fakeSpocs);
+
+      assert.deepEqual(result[0], { id: 1 });
+    });
+    it("should return simple structure and do nothing with no spocs", () => {
+      const { data: result } = feed.migrateFlightId([]);
+
+      assert.equal(result.length, 0);
+    });
+  });
+
+  describe("#isBelowFrequencyCap", () => {
+    it("should return true if there are no flight impressions", () => {
+      const fakeImpressions = {
+        seen: [Date.now() - 1],
+      };
+      const fakeSpoc = {
+        flight_id: "not-seen",
+        caps: {
+          lifetime: 3,
+          flight: {
+            count: 1,
+            period: 1,
+          },
+        },
+      };
+
+      const result = feed.isBelowFrequencyCap(fakeImpressions, fakeSpoc);
+
+      assert.isTrue(result);
+    });
+    it("should return true if there are no flight caps", () => {
+      const fakeImpressions = {
+        seen: [Date.now() - 1],
+      };
+      const fakeSpoc = {
+        flight_id: "seen",
+        caps: {
+          lifetime: 3,
+        },
+      };
+
+      const result = feed.isBelowFrequencyCap(fakeImpressions, fakeSpoc);
+
+      assert.isTrue(result);
+    });
+
+    it("should return false if lifetime cap is hit", () => {
+      const fakeImpressions = {
+        seen: [Date.now() - 1],
+      };
+      const fakeSpoc = {
+        flight_id: "seen",
+        caps: {
+          lifetime: 1,
+          flight: {
+            count: 3,
+            period: 1,
+          },
+        },
+      };
+
+      const result = feed.isBelowFrequencyCap(fakeImpressions, fakeSpoc);
+
+      assert.isFalse(result);
+    });
+
+    it("should return false if time based cap is hit", () => {
+      const fakeImpressions = {
+        seen: [Date.now() - 1],
+      };
+      const fakeSpoc = {
+        flight_id: "seen",
+        caps: {
+          lifetime: 3,
+          flight: {
+            count: 1,
+            period: 1,
+          },
+        },
+      };
+
+      const result = feed.isBelowFrequencyCap(fakeImpressions, fakeSpoc);
+
+      assert.isFalse(result);
+    });
+  });
+
+  describe("#retryFeed", () => {
+    it("should retry a feed fetch", async () => {
+      sandbox.stub(feed, "getComponentFeed").returns(Promise.resolve({}));
+      sandbox.stub(feed, "filterRecommendations").returns({});
+      sandbox.spy(feed.store, "dispatch");
+
+      await feed.retryFeed({ url: "https://feed.com" });
+
+      assert.calledOnce(feed.getComponentFeed);
+      assert.calledOnce(feed.filterRecommendations);
+      assert.calledOnce(feed.store.dispatch);
+      assert.equal(
+        feed.store.dispatch.firstCall.args[0].type,
+        "DISCOVERY_STREAM_FEED_UPDATE"
+      );
+      assert.deepEqual(feed.store.dispatch.firstCall.args[0].data, {
+        feed: {},
+        url: "https://feed.com",
+      });
+    });
+  });
+
+  describe("#recordFlightImpression", () => {
+    it("should return false if time based cap is hit", () => {
+      sandbox.stub(feed, "readDataPref").returns({});
+      sandbox.stub(feed, "writeDataPref").returns();
+
+      feed.recordFlightImpression("seen");
+
+      assert.calledWith(feed.writeDataPref, SPOC_IMPRESSION_TRACKING_PREF, {
+        seen: [0],
+      });
+    });
+  });
+
+  describe("#recordBlockFlightId", () => {
+    it("should call writeDataPref with new flight id added", () => {
+      sandbox.stub(feed, "readDataPref").returns({ 1234: 1 });
+      sandbox.stub(feed, "writeDataPref").returns();
+
+      feed.recordBlockFlightId("5678");
+
+      assert.calledOnce(feed.readDataPref);
+      assert.calledWith(feed.writeDataPref, "discoverystream.flight.blocks", {
+        1234: 1,
+        5678: 1,
+      });
+    });
+  });
+
+  describe("#cleanUpFlightImpressionPref", () => {
+    it("should remove flight-3 because it is no longer being used", async () => {
+      const fakeSpocs = {
+        spocs: {
+          items: [
+            {
+              flight_id: "flight-1",
+              caps: {
+                lifetime: 3,
+                flight: {
+                  count: 1,
+                  period: 1,
+                },
+              },
+            },
+            {
+              flight_id: "flight-2",
+              caps: {
+                lifetime: 3,
+                flight: {
+                  count: 1,
+                  period: 1,
+                },
+              },
+            },
+          ],
+        },
+      };
+      const fakeImpressions = {
+        "flight-2": [Date.now() - 1],
+        "flight-3": [Date.now() - 1],
+      };
+      sandbox.stub(feed, "getPlacements").returns([{ name: "spocs" }]);
+      sandbox.stub(feed, "readDataPref").returns(fakeImpressions);
+      sandbox.stub(feed, "writeDataPref").returns();
+
+      feed.cleanUpFlightImpressionPref(fakeSpocs);
+
+      assert.calledWith(feed.writeDataPref, SPOC_IMPRESSION_TRACKING_PREF, {
+        "flight-2": [-1],
+      });
+    });
+  });
+
+  describe("#recordTopRecImpressions", () => {
+    it("should add a rec id to the rec impression pref", () => {
+      sandbox.stub(feed, "readDataPref").returns({});
+      sandbox.stub(feed, "writeDataPref");
+
+      feed.recordTopRecImpressions("rec");
+
+      assert.calledWith(feed.writeDataPref, REC_IMPRESSION_TRACKING_PREF, {
+        rec: 0,
+      });
+    });
+    it("should not add an impression if it already exists", () => {
+      sandbox.stub(feed, "readDataPref").returns({ rec: 4 });
+      sandbox.stub(feed, "writeDataPref");
+
+      feed.recordTopRecImpressions("rec");
+
+      assert.notCalled(feed.writeDataPref);
+    });
+  });
+
+  describe("#cleanUpTopRecImpressionPref", () => {
+    it("should remove recs no longer being used", () => {
+      const newFeeds = {
+        "https://foo.com": {
+          data: {
+            recommendations: [
+              {
+                id: "rec1",
+              },
+              {
+                id: "rec2",
+              },
+            ],
+          },
+        },
+        "https://bar.com": {
+          data: {
+            recommendations: [
+              {
+                id: "rec3",
+              },
+              {
+                id: "rec4",
+              },
+            ],
+          },
+        },
+      };
+      const fakeImpressions = {
+        rec2: Date.now() - 1,
+        rec3: Date.now() - 1,
+        rec5: Date.now() - 1,
+      };
+      sandbox.stub(feed, "readDataPref").returns(fakeImpressions);
+      sandbox.stub(feed, "writeDataPref").returns();
+
+      feed.cleanUpTopRecImpressionPref(newFeeds);
+
+      assert.calledWith(feed.writeDataPref, REC_IMPRESSION_TRACKING_PREF, {
+        rec2: -1,
+        rec3: -1,
+      });
+    });
+  });
+
+  describe("#writeDataPref", () => {
+    it("should call Services.prefs.setStringPref", () => {
+      sandbox.spy(feed.store, "dispatch");
+      const fakeImpressions = {
+        foo: [Date.now() - 1],
+        bar: [Date.now() - 1],
+      };
+
+      feed.writeDataPref(SPOC_IMPRESSION_TRACKING_PREF, fakeImpressions);
+
+      assert.calledWithMatch(feed.store.dispatch, {
+        data: {
+          name: SPOC_IMPRESSION_TRACKING_PREF,
+          value: JSON.stringify(fakeImpressions),
+        },
+        type: at.SET_PREF,
+      });
+    });
+  });
+
+  describe("#addEndpointQuery", () => {
+    const url = "https://spocs.getpocket.com/spocs";
+
+    it("should return same url with no query", () => {
+      const result = feed.addEndpointQuery(url, "");
+      assert.equal(result, url);
+    });
+
+    it("should add multiple query params to standard url", () => {
+      const params = "?first=first&second=second";
+      const result = feed.addEndpointQuery(url, params);
+      assert.equal(result, url + params);
+    });
+
+    it("should add multiple query params to url with a query already", () => {
+      const params = "first=first&second=second";
+      const initialParams = "?zero=zero";
+      const result = feed.addEndpointQuery(
+        `${url}${initialParams}`,
+        `?${params}`
+      );
+      assert.equal(result, `${url}${initialParams}&${params}`);
+    });
+  });
+
+  describe("#readDataPref", () => {
+    it("should return what's in Services.prefs.getStringPref", () => {
+      const fakeImpressions = {
+        foo: [Date.now() - 1],
+        bar: [Date.now() - 1],
+      };
+      setPref(SPOC_IMPRESSION_TRACKING_PREF, fakeImpressions);
+
+      const result = feed.readDataPref(SPOC_IMPRESSION_TRACKING_PREF);
+
+      assert.deepEqual(result, fakeImpressions);
+    });
+  });
+
+  describe("#setupPrefs", () => {
+    it("should call setupPrefs", async () => {
+      sandbox.spy(feed, "setupPrefs");
+      feed.onAction({
+        type: at.INIT,
+      });
+      assert.calledOnce(feed.setupPrefs);
+    });
+    it("should dispatch to at.DISCOVERY_STREAM_PREFS_SETUP with proper data", async () => {
+      sandbox.spy(feed.store, "dispatch");
+      globals.set("ExperimentAPI", {
+        getExperimentMetaData: () => ({
+          slug: "experimentId",
+          branch: {
+            slug: "branchId",
+          },
+        }),
+        getRolloutMetaData: () => ({}),
+      });
+      global.Services.prefs.getBoolPref
+        .withArgs("extensions.pocket.enabled")
+        .returns(true);
+      feed.store.getState = () => ({
+        Prefs: {
+          values: {
+            region: "CA",
+            pocketConfig: {
+              recentSavesEnabled: true,
+              hideDescriptions: false,
+              hideDescriptionsRegions: "US,CA,GB",
+              compactImages: true,
+              imageGradient: true,
+              newSponsoredLabel: true,
+              titleLines: "1",
+              descLines: "1",
+              readTime: true,
+              saveToPocketCard: false,
+              saveToPocketCardRegions: "US,CA,GB",
+            },
+          },
+        },
+      });
+      feed.setupPrefs();
+      assert.deepEqual(feed.store.dispatch.firstCall.args[0].data, {
+        utmSource: "pocket-newtab",
+        utmCampaign: "experimentId",
+        utmContent: "branchId",
+      });
+      assert.deepEqual(feed.store.dispatch.secondCall.args[0].data, {
+        recentSavesEnabled: true,
+        pocketButtonEnabled: true,
+        saveToPocketCard: true,
+        hideDescriptions: true,
+        compactImages: true,
+        imageGradient: true,
+        newSponsoredLabel: true,
+        titleLines: "1",
+        descLines: "1",
+        readTime: true,
+      });
+    });
+  });
+
+  describe("#onAction: DISCOVERY_STREAM_IMPRESSION_STATS", () => {
+    it("should call recordTopRecImpressions from DISCOVERY_STREAM_IMPRESSION_STATS", async () => {
+      sandbox.stub(feed, "recordTopRecImpressions").returns();
+      await feed.onAction({
+        type: at.DISCOVERY_STREAM_IMPRESSION_STATS,
+        data: { tiles: [{ id: "seen" }] },
+      });
+
+      assert.calledWith(feed.recordTopRecImpressions, "seen");
+    });
+  });
+
+  describe("#onAction: DISCOVERY_STREAM_SPOC_IMPRESSION", () => {
+    beforeEach(() => {
+      const data = {
+        spocs: {
+          items: [
+            {
+              id: 1,
+              flight_id: "seen",
+              caps: {
+                lifetime: 3,
+                flight: {
+                  count: 1,
+                  period: 1,
+                },
+              },
+            },
+            {
+              id: 2,
+              flight_id: "not-seen",
+              caps: {
+                lifetime: 3,
+                flight: {
+                  count: 1,
+                  period: 1,
+                },
+              },
+            },
+          ],
+        },
+      };
+      sandbox.stub(feed.store, "getState").returns({
+        DiscoveryStream: {
+          spocs: {
+            data,
+          },
+        },
+      });
+    });
+
+    it("should call dispatch to ac.AlsoToPreloaded with filtered spoc data", async () => {
+      sandbox.stub(feed, "getPlacements").returns([{ name: "spocs" }]);
+      Object.defineProperty(feed, "showSpocs", { get: () => true });
+      const fakeImpressions = {
+        seen: [Date.now() - 1],
+      };
+      const result = {
+        spocs: {
+          items: [
+            {
+              id: 2,
+              flight_id: "not-seen",
+              caps: {
+                lifetime: 3,
+                flight: {
+                  count: 1,
+                  period: 1,
+                },
+              },
+            },
+          ],
+        },
+      };
+      sandbox.stub(feed, "recordFlightImpression").returns();
+      sandbox.stub(feed, "readDataPref").returns(fakeImpressions);
+      sandbox.spy(feed.store, "dispatch");
+
+      await feed.onAction({
+        type: at.DISCOVERY_STREAM_SPOC_IMPRESSION,
+        data: { flightId: "seen" },
+      });
+
+      assert.deepEqual(
+        feed.store.dispatch.secondCall.args[0].data.spocs,
+        result
+      );
+    });
+    it("should not call dispatch to ac.AlsoToPreloaded if spocs were not changed by frequency capping", async () => {
+      sandbox.stub(feed, "getPlacements").returns([{ name: "spocs" }]);
+      Object.defineProperty(feed, "showSpocs", { get: () => true });
+      const fakeImpressions = {};
+      sandbox.stub(feed, "recordFlightImpression").returns();
+      sandbox.stub(feed, "readDataPref").returns(fakeImpressions);
+      sandbox.spy(feed.store, "dispatch");
+
+      await feed.onAction({
+        type: at.DISCOVERY_STREAM_SPOC_IMPRESSION,
+        data: { flight_id: "seen" },
+      });
+
+      assert.notCalled(feed.store.dispatch);
+    });
+    it("should attempt feq cap on valid spocs with placements on impression", async () => {
+      sandbox.restore();
+      Object.defineProperty(feed, "showSpocs", { get: () => true });
+      const fakeImpressions = {};
+      sandbox.stub(feed, "recordFlightImpression").returns();
+      sandbox.stub(feed, "readDataPref").returns(fakeImpressions);
+      sandbox.spy(feed.store, "dispatch");
+      sandbox.spy(feed, "frequencyCapSpocs");
+
+      const data = {
+        spocs: {
+          items: [
+            {
+              id: 2,
+              flight_id: "seen-2",
+              caps: {
+                lifetime: 3,
+                flight: {
+                  count: 1,
+                  period: 1,
+                },
+              },
+            },
+          ],
+        },
+      };
+      sandbox.stub(feed.store, "getState").returns({
+        DiscoveryStream: {
+          spocs: {
+            data,
+            placements: [{ name: "spocs" }, { name: "notSpocs" }],
+          },
+        },
+      });
+
+      await feed.onAction({
+        type: at.DISCOVERY_STREAM_SPOC_IMPRESSION,
+        data: { flight_id: "doesn't matter" },
+      });
+
+      assert.calledOnce(feed.frequencyCapSpocs);
+      assert.calledWith(feed.frequencyCapSpocs, data.spocs.items);
+    });
+  });
+
+  describe("#onAction: PLACES_LINK_BLOCKED", () => {
+    beforeEach(() => {
+      const data = {
+        spocs: {
+          items: [
+            {
+              id: 1,
+              flight_id: "foo",
+              url: "foo.com",
+            },
+            {
+              id: 2,
+              flight_id: "bar",
+              url: "bar.com",
+            },
+          ],
+        },
+      };
+      sandbox.stub(feed.store, "getState").returns({
+        DiscoveryStream: {
+          spocs: {
+            data,
+            placements: [{ name: "spocs" }],
+          },
+        },
+      });
+    });
+
+    it("should call dispatch if found a blocked spoc", async () => {
+      Object.defineProperty(feed, "showSpocs", { get: () => true });
+
+      sandbox.spy(feed.store, "dispatch");
+
+      await feed.onAction({
+        type: at.PLACES_LINK_BLOCKED,
+        data: { url: "foo.com" },
+      });
+
+      assert.deepEqual(
+        feed.store.dispatch.firstCall.args[0].data.url,
+        "foo.com"
+      );
+    });
+    it("should dispatch once if the blocked is not a SPOC", async () => {
+      Object.defineProperty(feed, "showSpocs", { get: () => true });
+      sandbox.spy(feed.store, "dispatch");
+
+      await feed.onAction({
+        type: at.PLACES_LINK_BLOCKED,
+        data: { url: "not_a_spoc.com" },
+      });
+
+      assert.calledOnce(feed.store.dispatch);
+      assert.deepEqual(
+        feed.store.dispatch.firstCall.args[0].data.url,
+        "not_a_spoc.com"
+      );
+    });
+    it("should dispatch a DISCOVERY_STREAM_SPOC_BLOCKED for a blocked spoc", async () => {
+      Object.defineProperty(feed, "showSpocs", { get: () => true });
+      sandbox.spy(feed.store, "dispatch");
+
+      await feed.onAction({
+        type: at.PLACES_LINK_BLOCKED,
+        data: { url: "foo.com" },
+      });
+
+      assert.equal(
+        feed.store.dispatch.secondCall.args[0].type,
+        "DISCOVERY_STREAM_SPOC_BLOCKED"
+      );
+    });
+  });
+
+  describe("#onAction: BLOCK_URL", () => {
+    it("should call recordBlockFlightId whith BLOCK_URL", async () => {
+      sandbox.stub(feed, "recordBlockFlightId").returns();
+
+      await feed.onAction({
+        type: at.BLOCK_URL,
+        data: [
+          {
+            flight_id: "1234",
+          },
+        ],
+      });
+
+      assert.calledWith(feed.recordBlockFlightId, "1234");
+    });
+  });
+
+  describe("#onAction: INIT", () => {
+    it("should be .loaded=false before initialization", () => {
+      assert.isFalse(feed.loaded);
+    });
+    it("should load data and set .loaded=true if config.enabled is true", async () => {
+      sandbox.stub(feed.cache, "set").returns(Promise.resolve());
+      setPref(CONFIG_PREF_NAME, { enabled: true });
+      sandbox.stub(feed, "loadLayout").returns(Promise.resolve());
+
+      await feed.onAction({ type: at.INIT });
+
+      assert.calledOnce(feed.loadLayout);
+      assert.isTrue(feed.loaded);
+    });
+  });
+
+  describe("#onAction: DISCOVERY_STREAM_CONFIG_SET_VALUE", async () => {
+    it("should add the new value to the pref without changing the existing values", async () => {
+      sandbox.spy(feed.store, "dispatch");
+      setPref(CONFIG_PREF_NAME, { enabled: true, other: "value" });
+
+      await feed.onAction({
+        type: at.DISCOVERY_STREAM_CONFIG_SET_VALUE,
+        data: { name: "api_key_pref", value: "foo" },
+      });
+
+      assert.calledWithMatch(feed.store.dispatch, {
+        data: {
+          name: CONFIG_PREF_NAME,
+          value: JSON.stringify({
+            enabled: true,
+            other: "value",
+            api_key_pref: "foo",
+          }),
+        },
+        type: at.SET_PREF,
+      });
+    });
+  });
+
+  describe("#onAction: DISCOVERY_STREAM_POCKET_STATE_INIT", async () => {
+    it("should call setupPocketState", async () => {
+      sandbox.spy(feed, "setupPocketState");
+      feed.onAction({
+        type: at.DISCOVERY_STREAM_POCKET_STATE_INIT,
+        meta: { fromTarget: {} },
+      });
+      assert.calledOnce(feed.setupPocketState);
+    });
+  });
+
+  describe("#onAction: DISCOVERY_STREAM_CONFIG_RESET", async () => {
+    it("should call configReset", async () => {
+      sandbox.spy(feed, "configReset");
+      feed.onAction({
+        type: at.DISCOVERY_STREAM_CONFIG_RESET,
+      });
+      assert.calledOnce(feed.configReset);
+    });
+  });
+
+  describe("#onAction: DISCOVERY_STREAM_CONFIG_RESET_DEFAULTS", async () => {
+    it("Should dispatch CLEAR_PREF with pref name", async () => {
+      sandbox.spy(feed.store, "dispatch");
+      await feed.onAction({
+        type: at.DISCOVERY_STREAM_CONFIG_RESET_DEFAULTS,
+      });
+
+      assert.calledWithMatch(feed.store.dispatch, {
+        data: {
+          name: CONFIG_PREF_NAME,
+        },
+        type: at.CLEAR_PREF,
+      });
+    });
+  });
+
+  describe("#onAction: DISCOVERY_STREAM_RETRY_FEED", async () => {
+    it("should call retryFeed", async () => {
+      sandbox.spy(feed, "retryFeed");
+      feed.onAction({
+        type: at.DISCOVERY_STREAM_RETRY_FEED,
+        data: { feed: { url: "https://feed.com" } },
+      });
+      assert.calledOnce(feed.retryFeed);
+      assert.calledWith(feed.retryFeed, { url: "https://feed.com" });
+    });
+  });
+
+  describe("#onAction: DISCOVERY_STREAM_CONFIG_CHANGE", () => {
+    it("should call this.loadLayout if config.enabled changes to true ", async () => {
+      sandbox.stub(feed.cache, "set").returns(Promise.resolve());
+      // First initialize
+      await feed.onAction({ type: at.INIT });
+      assert.isFalse(feed.loaded);
+
+      // force clear cached pref value
+      feed._prefCache = {};
+      setPref(CONFIG_PREF_NAME, { enabled: true });
+
+      sandbox.stub(feed, "resetCache").returns(Promise.resolve());
+      sandbox.stub(feed, "loadLayout").returns(Promise.resolve());
+      await feed.onAction({ type: at.DISCOVERY_STREAM_CONFIG_CHANGE });
+
+      assert.calledOnce(feed.loadLayout);
+      assert.calledOnce(feed.resetCache);
+      assert.isTrue(feed.loaded);
+    });
+    it("should clear the cache if a config change happens and config.enabled is true", async () => {
+      sandbox.stub(feed.cache, "set").returns(Promise.resolve());
+      // force clear cached pref value
+      feed._prefCache = {};
+      setPref(CONFIG_PREF_NAME, { enabled: true });
+
+      sandbox.stub(feed, "resetCache").returns(Promise.resolve());
+      await feed.onAction({ type: at.DISCOVERY_STREAM_CONFIG_CHANGE });
+
+      assert.calledOnce(feed.resetCache);
+    });
+    it("should dispatch DISCOVERY_STREAM_LAYOUT_RESET from DISCOVERY_STREAM_CONFIG_CHANGE", async () => {
+      sandbox.stub(feed, "resetDataPrefs");
+      sandbox.stub(feed, "resetCache").resolves();
+      sandbox.stub(feed, "enable").resolves();
+      setPref(CONFIG_PREF_NAME, { enabled: true });
+      sandbox.spy(feed.store, "dispatch");
+
+      await feed.onAction({ type: at.DISCOVERY_STREAM_CONFIG_CHANGE });
+
+      assert.calledWithMatch(feed.store.dispatch, {
+        type: at.DISCOVERY_STREAM_LAYOUT_RESET,
+      });
+    });
+    it("should not call this.loadLayout if config.enabled changes to false", async () => {
+      sandbox.stub(feed.cache, "set").returns(Promise.resolve());
+      // force clear cached pref value
+      feed._prefCache = {};
+      setPref(CONFIG_PREF_NAME, { enabled: true });
+
+      await feed.onAction({ type: at.INIT });
+      assert.isTrue(feed.loaded);
+
+      feed._prefCache = {};
+      setPref(CONFIG_PREF_NAME, { enabled: false });
+      sandbox.stub(feed, "resetCache").returns(Promise.resolve());
+      sandbox.stub(feed, "loadLayout").returns(Promise.resolve());
+      await feed.onAction({ type: at.DISCOVERY_STREAM_CONFIG_CHANGE });
+
+      assert.notCalled(feed.loadLayout);
+      assert.calledOnce(feed.resetCache);
+      assert.isFalse(feed.loaded);
+    });
+  });
+
+  describe("#onAction: UNINIT", () => {
+    it("should reset pref cache", async () => {
+      feed._prefCache = { cached: "value" };
+
+      await feed.onAction({ type: at.UNINIT });
+
+      assert.deepEqual(feed._prefCache, {});
+    });
+  });
+
+  describe("#onAction: PREF_CHANGED", () => {
+    it("should update state.DiscoveryStream.config when the pref changes", async () => {
+      setPref(CONFIG_PREF_NAME, {
+        enabled: true,
+        api_key_pref: "foo",
+      });
+
+      assert.deepEqual(feed.store.getState().DiscoveryStream.config, {
+        enabled: true,
+        api_key_pref: "foo",
+      });
+    });
+    it("should fire loadSpocs is showSponsored pref changes", async () => {
+      sandbox.stub(feed, "loadSpocs").returns(Promise.resolve());
+
+      await feed.onAction({
+        type: at.PREF_CHANGED,
+        data: { name: "showSponsored" },
+      });
+
+      assert.calledOnce(feed.loadSpocs);
+    });
+    it("should fire onPrefChange when pocketConfig pref changes", async () => {
+      sandbox.stub(feed, "onPrefChange").returns(Promise.resolve());
+
+      await feed.onAction({
+        type: at.PREF_CHANGED,
+        data: { name: "pocketConfig", value: false },
+      });
+
+      assert.calledOnce(feed.onPrefChange);
+    });
+    it("should fire onCollectionsChanged when collections pref changes", async () => {
+      sandbox.stub(feed, "onCollectionsChanged").returns(Promise.resolve());
+
+      await feed.onAction({
+        type: at.PREF_CHANGED,
+        data: { name: "discoverystream.sponsored-collections.enabled" },
+      });
+
+      assert.calledOnce(feed.onCollectionsChanged);
+    });
+    it("should re enable stories when top stories is turned on", async () => {
+      sandbox.stub(feed, "refreshAll").returns(Promise.resolve());
+      feed.loaded = true;
+      setPref(CONFIG_PREF_NAME, {
+        enabled: true,
+      });
+
+      await feed.onAction({
+        type: at.PREF_CHANGED,
+        data: { name: "feeds.section.topstories", value: true },
+      });
+
+      assert.calledOnce(feed.refreshAll);
+    });
+    it("shoud update allowlist", async () => {
+      assert.equal(
+        feed.store.getState().Prefs.values[ENDPOINTS_PREF_NAME],
+        DUMMY_ENDPOINT
+      );
+      setPref(ENDPOINTS_PREF_NAME, "sick-kickflip.mozilla.net");
+      assert.equal(
+        feed.store.getState().Prefs.values[ENDPOINTS_PREF_NAME],
+        "sick-kickflip.mozilla.net"
+      );
+    });
+  });
+
+  describe("#onAction: SYSTEM_TICK", () => {
+    it("should not refresh if DiscoveryStream has not been loaded", async () => {
+      sandbox.stub(feed, "refreshAll").resolves();
+      setPref(CONFIG_PREF_NAME, { enabled: true });
+
+      await feed.onAction({ type: at.SYSTEM_TICK });
+      assert.notCalled(feed.refreshAll);
+    });
+
+    it("should not refresh if no caches are expired", async () => {
+      sandbox.stub(feed.cache, "set").resolves();
+      setPref(CONFIG_PREF_NAME, { enabled: true });
+
+      await feed.onAction({ type: at.INIT });
+
+      sandbox.stub(feed, "checkIfAnyCacheExpired").resolves(false);
+      sandbox.stub(feed, "refreshAll").resolves();
+
+      await feed.onAction({ type: at.SYSTEM_TICK });
+      assert.notCalled(feed.refreshAll);
+    });
+
+    it("should refresh if DiscoveryStream has been loaded at least once and a cache has expired", async () => {
+      sandbox.stub(feed.cache, "set").resolves();
+      setPref(CONFIG_PREF_NAME, { enabled: true });
+
+      await feed.onAction({ type: at.INIT });
+
+      sandbox.stub(feed, "checkIfAnyCacheExpired").resolves(true);
+      sandbox.stub(feed, "refreshAll").resolves();
+
+      await feed.onAction({ type: at.SYSTEM_TICK });
+      assert.calledOnce(feed.refreshAll);
+    });
+
+    it("should refresh and not update open tabs if DiscoveryStream has been loaded at least once", async () => {
+      sandbox.stub(feed.cache, "set").resolves();
+      setPref(CONFIG_PREF_NAME, { enabled: true });
+
+      await feed.onAction({ type: at.INIT });
+
+      sandbox.stub(feed, "checkIfAnyCacheExpired").resolves(true);
+      sandbox.stub(feed, "refreshAll").resolves();
+
+      await feed.onAction({ type: at.SYSTEM_TICK });
+      assert.calledWith(feed.refreshAll, { updateOpenTabs: false });
+    });
+  });
+
+  describe("#onCollectionsChanged", () => {
+    it("should call loadLayout when Pocket config changes", async () => {
+      sandbox.stub(feed, "loadLayout").callsFake(dispatch => dispatch("foo"));
+      sandbox.stub(feed.store, "dispatch");
+      await feed.onCollectionsChanged();
+      assert.calledOnce(feed.loadLayout);
+      assert.calledWith(feed.store.dispatch, ac.AlsoToPreloaded("foo"));
+    });
+  });
+
+  describe("#enable", () => {
+    it("should pass along proper options to refreshAll from enable", async () => {
+      sandbox.stub(feed, "refreshAll");
+      await feed.enable();
+      assert.calledWith(feed.refreshAll, {});
+      await feed.enable({ updateOpenTabs: true });
+      assert.calledWith(feed.refreshAll, { updateOpenTabs: true });
+      await feed.enable({ isStartup: true });
+      assert.calledWith(feed.refreshAll, { isStartup: true });
+      await feed.enable({ updateOpenTabs: true, isStartup: true });
+      assert.calledWith(feed.refreshAll, {
+        updateOpenTabs: true,
+        isStartup: true,
+      });
+    });
+  });
+
+  describe("#onPrefChange", () => {
+    it("should call loadLayout when Pocket config changes", async () => {
+      sandbox.stub(feed, "loadLayout");
+      feed._prefCache.config = {
+        enabled: true,
+      };
+      await feed.onPrefChange();
+      assert.calledOnce(feed.loadLayout);
+    });
+    it("should update open tabs but not startup with onPrefChange", async () => {
+      sandbox.stub(feed, "refreshAll");
+      feed._prefCache.config = {
+        enabled: true,
+      };
+      await feed.onPrefChange();
+      assert.calledWith(feed.refreshAll, { updateOpenTabs: true });
+    });
+  });
+
+  describe("#onAction: PREF_SHOW_SPONSORED", () => {
+    it("should call loadSpocs when preference changes", async () => {
+      sandbox.stub(feed, "loadSpocs").resolves();
+      sandbox.stub(feed.store, "dispatch");
+
+      await feed.onAction({
+        type: at.PREF_CHANGED,
+        data: { name: "showSponsored" },
+      });
+
+      assert.calledOnce(feed.loadSpocs);
+      const [dispatchFn] = feed.loadSpocs.firstCall.args;
+      dispatchFn({});
+      assert.calledWith(feed.store.dispatch, ac.BroadcastToContent({}));
+    });
+  });
+
+  describe("#onAction: DISCOVERY_STREAM_DEV_SYNC_RS", () => {
+    it("should fire remote settings pollChanges", async () => {
+      sandbox.stub(global.RemoteSettings, "pollChanges").returns();
+      await feed.onAction({
+        type: at.DISCOVERY_STREAM_DEV_SYNC_RS,
+      });
+      assert.calledOnce(global.RemoteSettings.pollChanges);
+    });
+  });
+
+  describe("#onAction: DISCOVERY_STREAM_DEV_SYSTEM_TICK", () => {
+    it("should refresh if DiscoveryStream has been loaded at least once and a cache has expired", async () => {
+      sandbox.stub(feed.cache, "set").resolves();
+      setPref(CONFIG_PREF_NAME, { enabled: true });
+
+      await feed.onAction({ type: at.INIT });
+
+      sandbox.stub(feed, "checkIfAnyCacheExpired").resolves(true);
+      sandbox.stub(feed, "refreshAll").resolves();
+
+      await feed.onAction({ type: at.DISCOVERY_STREAM_DEV_SYSTEM_TICK });
+      assert.calledOnce(feed.refreshAll);
+    });
+  });
+
+  describe("#onAction: DISCOVERY_STREAM_DEV_EXPIRE_CACHE", () => {
+    it("should fire resetCache", async () => {
+      sandbox.stub(feed, "resetContentCache").returns();
+      await feed.onAction({
+        type: at.DISCOVERY_STREAM_DEV_EXPIRE_CACHE,
+      });
+      assert.calledOnce(feed.resetContentCache);
+    });
+  });
+
+  describe("#spocsCacheUpdateTime", () => {
+    it("should call setupSpocsCacheUpdateTime", () => {
+      const defaultCacheTime = 30 * 60 * 1000;
+      sandbox.spy(feed, "setupSpocsCacheUpdateTime");
+      const cacheTime = feed.spocsCacheUpdateTime;
+      assert.equal(feed._spocsCacheUpdateTime, defaultCacheTime);
+      assert.equal(cacheTime, defaultCacheTime);
+      assert.calledOnce(feed.setupSpocsCacheUpdateTime);
+    });
+    it("should return _spocsCacheUpdateTime", () => {
+      sandbox.spy(feed, "setupSpocsCacheUpdateTime");
+      const testCacheTime = 123;
+      feed._spocsCacheUpdateTime = testCacheTime;
+      const cacheTime = feed.spocsCacheUpdateTime;
+      // Ensure _spocsCacheUpdateTime was not changed.
+      assert.equal(feed._spocsCacheUpdateTime, testCacheTime);
+      assert.equal(cacheTime, testCacheTime);
+      assert.notCalled(feed.setupSpocsCacheUpdateTime);
+    });
+  });
+
+  describe("#setupSpocsCacheUpdateTime", () => {
+    it("should set _spocsCacheUpdateTime with default value", () => {
+      const defaultCacheTime = 30 * 60 * 1000;
+      feed.setupSpocsCacheUpdateTime();
+      assert.equal(feed._spocsCacheUpdateTime, defaultCacheTime);
+    });
+    it("should set _spocsCacheUpdateTime with min", () => {
+      const defaultCacheTime = 30 * 60 * 1000;
+      feed.store.getState = () => ({
+        Prefs: {
+          values: {
+            pocketConfig: {
+              spocsCacheTimeout: 1,
+            },
+          },
+        },
+      });
+      feed.setupSpocsCacheUpdateTime();
+      assert.equal(feed._spocsCacheUpdateTime, defaultCacheTime);
+    });
+    it("should set _spocsCacheUpdateTime with max", () => {
+      const defaultCacheTime = 30 * 60 * 1000;
+      feed.store.getState = () => ({
+        Prefs: {
+          values: {
+            pocketConfig: {
+              spocsCacheTimeout: 31,
+            },
+          },
+        },
+      });
+      feed.setupSpocsCacheUpdateTime();
+      assert.equal(feed._spocsCacheUpdateTime, defaultCacheTime);
+    });
+    it("should set _spocsCacheUpdateTime with spocsCacheTimeout", () => {
+      feed.store.getState = () => ({
+        Prefs: {
+          values: {
+            pocketConfig: {
+              spocsCacheTimeout: 20,
+            },
+          },
+        },
+      });
+      feed.setupSpocsCacheUpdateTime();
+      assert.equal(feed._spocsCacheUpdateTime, 20 * 60 * 1000);
+    });
+  });
+
+  describe("#isExpired", () => {
+    it("should throw if the key is not valid", () => {
+      assert.throws(() => {
+        feed.isExpired({}, "foo");
+      });
+    });
+    it("should return false for spocs on startup for content under 1 week", () => {
+      const spocs = { lastUpdated: Date.now() };
+      const result = feed.isExpired({
+        cachedData: { spocs },
+        key: "spocs",
+        isStartup: true,
+      });
+
+      assert.isFalse(result);
+    });
+    it("should return true for spocs for isStartup=false after 30 mins", () => {
+      const spocs = { lastUpdated: Date.now() };
+      clock.tick(THIRTY_MINUTES + 1);
+      const result = feed.isExpired({ cachedData: { spocs }, key: "spocs" });
+
+      assert.isTrue(result);
+    });
+    it("should return true for spocs on startup for content over 1 week", () => {
+      const spocs = { lastUpdated: Date.now() };
+      clock.tick(ONE_WEEK + 1);
+      const result = feed.isExpired({
+        cachedData: { spocs },
+        key: "spocs",
+        isStartup: true,
+      });
+
+      assert.isTrue(result);
+    });
+  });
+
+  describe("#checkIfAnyCacheExpired", () => {
+    let cache;
+    beforeEach(() => {
+      cache = {
+        feeds: { "foo.com": { lastUpdated: Date.now() } },
+        spocs: { lastUpdated: Date.now() },
+      };
+      Object.defineProperty(feed, "showSpocs", { get: () => true });
+      sandbox.stub(feed.cache, "get").resolves(cache);
+    });
+
+    it("should return false if nothing in the cache is expired", async () => {
+      const result = await feed.checkIfAnyCacheExpired();
+      assert.isFalse(result);
+    });
+    it("should return true if .spocs is missing", async () => {
+      delete cache.spocs;
+      assert.isTrue(await feed.checkIfAnyCacheExpired());
+    });
+    it("should return true if .spocs is expired", async () => {
+      clock.tick(THIRTY_MINUTES + 1);
+      // Update other caches we aren't testing
+      cache.spocs.lastUpdated = Date.now();
+      cache.feeds["foo.com"].lastUpdate = Date.now();
+
+      assert.isTrue(await feed.checkIfAnyCacheExpired());
+    });
+
+    it("should return true if .feeds is missing", async () => {
+      delete cache.feeds;
+      assert.isTrue(await feed.checkIfAnyCacheExpired());
+    });
+    it("should return true if data for .feeds[url] is missing", async () => {
+      cache.feeds["foo.com"] = null;
+      assert.isTrue(await feed.checkIfAnyCacheExpired());
+    });
+    it("should return true if data for .feeds[url] is expired", async () => {
+      clock.tick(THIRTY_MINUTES + 1);
+      // Update other caches we aren't testing
+      cache.spocs.lastUpdate = Date.now();
+      assert.isTrue(await feed.checkIfAnyCacheExpired());
+    });
+  });
+
+  describe("#refreshAll", () => {
+    beforeEach(() => {
+      sandbox.stub(feed, "loadLayout").resolves();
+      sandbox.stub(feed, "loadComponentFeeds").resolves();
+      sandbox.stub(feed, "loadSpocs").resolves();
+      sandbox.spy(feed.store, "dispatch");
+      Object.defineProperty(feed, "showSpocs", { get: () => true });
+    });
+
+    it("should call layout, component, spocs update and telemetry reporting functions", async () => {
+      await feed.refreshAll();
+
+      assert.calledOnce(feed.loadLayout);
+      assert.calledOnce(feed.loadComponentFeeds);
+      assert.calledOnce(feed.loadSpocs);
+    });
+    it("should pass in dispatch wrapped with broadcast if options.updateOpenTabs is true", async () => {
+      await feed.refreshAll({ updateOpenTabs: true });
+      [feed.loadLayout, feed.loadComponentFeeds, feed.loadSpocs].forEach(fn => {
+        assert.calledOnce(fn);
+        const result = fn.firstCall.args[0]({ type: "FOO" });
+        assert.isTrue(au.isBroadcastToContent(result));
+      });
+    });
+    it("should pass in dispatch with regular actions if options.updateOpenTabs is false", async () => {
+      await feed.refreshAll({ updateOpenTabs: false });
+      [feed.loadLayout, feed.loadComponentFeeds, feed.loadSpocs].forEach(fn => {
+        assert.calledOnce(fn);
+        const result = fn.firstCall.args[0]({ type: "FOO" });
+        assert.deepEqual(result, { type: "FOO" });
+      });
+    });
+    it("should set loaded to true if loadSpocs and loadComponentFeeds fails", async () => {
+      feed.loadComponentFeeds.rejects("loadComponentFeeds error");
+      feed.loadSpocs.rejects("loadSpocs error");
+
+      await feed.enable();
+
+      assert.isTrue(feed.loaded);
+    });
+    it("should call loadComponentFeeds and loadSpocs in Promise.all", async () => {
+      sandbox.stub(global.Promise, "all").resolves();
+
+      await feed.refreshAll();
+
+      assert.calledOnce(global.Promise.all);
+      const { args } = global.Promise.all.firstCall;
+      assert.equal(args[0].length, 2);
+    });
+    describe("test startup cache behaviour", () => {
+      beforeEach(() => {
+        feed._maybeUpdateCachedData.restore();
+        sandbox.stub(feed.cache, "set").resolves();
+      });
+      it("should not refresh layout on startup if it is under THIRTY_MINUTES", async () => {
+        feed.loadLayout.restore();
+        sandbox.stub(feed.cache, "get").resolves({
+          layout: { lastUpdated: Date.now(), layout: {} },
+        });
+        sandbox.stub(feed, "fetchFromEndpoint").resolves({ layout: {} });
+
+        await feed.refreshAll({ isStartup: true });
+
+        assert.notCalled(feed.fetchFromEndpoint);
+      });
+      it("should refresh spocs on startup if it was served from cache", async () => {
+        feed.loadSpocs.restore();
+        sandbox.stub(feed, "getPlacements").returns([{ name: "spocs" }]);
+        sandbox.stub(feed.cache, "get").resolves({
+          spocs: { lastUpdated: Date.now() },
+        });
+        clock.tick(THIRTY_MINUTES + 1);
+
+        await feed.refreshAll({ isStartup: true });
+
+        // Once from cache, once to update the store
+        assert.calledTwice(feed.store.dispatch);
+        assert.equal(
+          feed.store.dispatch.firstCall.args[0].type,
+          at.DISCOVERY_STREAM_SPOCS_UPDATE
+        );
+      });
+      it("should not refresh spocs on startup if it is under THIRTY_MINUTES", async () => {
+        feed.loadSpocs.restore();
+        sandbox.stub(feed.cache, "get").resolves({
+          spocs: { lastUpdated: Date.now() },
+        });
+        sandbox.stub(feed, "fetchFromEndpoint").resolves("data");
+
+        await feed.refreshAll({ isStartup: true });
+
+        assert.notCalled(feed.fetchFromEndpoint);
+      });
+      it("should refresh feeds on startup if it was served from cache", async () => {
+        feed.loadComponentFeeds.restore();
+
+        const fakeComponents = { components: [{ feed: { url: "foo.com" } }] };
+        const fakeLayout = [fakeComponents];
+        const fakeDiscoveryStream = {
+          DiscoveryStream: {
+            layout: fakeLayout,
+          },
+          Prefs: {
+            values: {
+              "feeds.section.topstories": true,
+              "feeds.system.topstories": true,
+            },
+          },
+        };
+        sandbox.stub(feed.store, "getState").returns(fakeDiscoveryStream);
+        sandbox.stub(feed, "rotate").callsFake(val => val);
+        sandbox
+          .stub(feed, "scoreItems")
+          .callsFake(val => ({ data: val, filtered: [], personalized: false }));
+        sandbox.stub(feed, "cleanUpTopRecImpressionPref").callsFake(val => val);
+
+        const fakeCache = {
+          feeds: { "foo.com": { lastUpdated: Date.now(), data: "data" } },
+        };
+        sandbox.stub(feed.cache, "get").resolves(fakeCache);
+        clock.tick(THIRTY_MINUTES + 1);
+        sandbox.stub(feed, "fetchFromEndpoint").resolves({
+          recommendations: "data",
+          settings: {
+            recsExpireTime: 1,
+          },
+        });
+
+        await feed.refreshAll({ isStartup: true });
+
+        assert.calledOnce(feed.fetchFromEndpoint);
+        // Once from cache, once to update the feed, once to update that all
+        // feeds are done.
+        assert.calledThrice(feed.store.dispatch);
+        assert.equal(
+          feed.store.dispatch.secondCall.args[0].type,
+          at.DISCOVERY_STREAM_FEEDS_UPDATE
+        );
+      });
+    });
+  });
+
+  describe("#scoreFeeds", () => {
+    beforeEach(() => {
+      sandbox.stub(feed.cache, "set").resolves();
+      sandbox.spy(feed.store, "dispatch");
+    });
+    it("should score feeds and set cache, and dispatch", async () => {
+      const fakeDiscoveryStream = {
+        Prefs: {
+          values: {
+            "discoverystream.spocs.personalized": true,
+            "discoverystream.recs.personalized": false,
+          },
+        },
+        Personalization: {
+          initialized: true,
+        },
+        DiscoveryStream: {
+          spocs: {
+            placements: [
+              { name: "placement1" },
+              { name: "placement2" },
+              { name: "placement3" },
+            ],
+          },
+        },
+      };
+      sandbox.stub(feed.store, "getState").returns(fakeDiscoveryStream);
+      const recsExpireTime = 5600;
+      const fakeImpressions = {
+        first: Date.now() - recsExpireTime * 1000,
+        third: Date.now(),
+      };
+      sandbox.stub(feed, "readDataPref").returns(fakeImpressions);
+      const fakeFeeds = {
+        data: {
+          "https://foo.com": {
+            data: {
+              recommendations: [
+                {
+                  id: "first",
+                  item_score: 0.7,
+                },
+                {
+                  id: "second",
+                  item_score: 0.6,
+                },
+              ],
+              settings: {
+                recsExpireTime,
+              },
+            },
+          },
+          "https://bar.com": {
+            data: {
+              recommendations: [
+                {
+                  id: "third",
+                  item_score: 0.4,
+                },
+                {
+                  id: "fourth",
+                  item_score: 0.6,
+                },
+                {
+                  id: "fifth",
+                  item_score: 0.8,
+                },
+              ],
+              settings: {
+                recsExpireTime,
+              },
+            },
+          },
+        },
+      };
+      const feedsTestResult = {
+        "https://foo.com": {
+          personalized: true,
+          data: {
+            recommendations: [
+              {
+                id: "second",
+                item_score: 0.6,
+                score: 0.6,
+              },
+              {
+                id: "first",
+                item_score: 0.7,
+                score: 0.7,
+              },
+            ],
+            settings: {
+              recsExpireTime,
+            },
+          },
+        },
+        "https://bar.com": {
+          personalized: true,
+          data: {
+            recommendations: [
+              {
+                id: "fifth",
+                item_score: 0.8,
+                score: 0.8,
+              },
+              {
+                id: "fourth",
+                item_score: 0.6,
+                score: 0.6,
+              },
+              {
+                id: "third",
+                item_score: 0.4,
+                score: 0.4,
+              },
+            ],
+            settings: {
+              recsExpireTime,
+            },
+          },
+        },
+      };
+
+      await feed.scoreFeeds(fakeFeeds);
+
+      assert.calledWith(feed.cache.set, "feeds", feedsTestResult);
+      assert.equal(
+        feed.store.dispatch.firstCall.args[0].type,
+        at.DISCOVERY_STREAM_FEED_UPDATE
+      );
+      assert.deepEqual(feed.store.dispatch.firstCall.args[0].data, {
+        url: "https://foo.com",
+        feed: feedsTestResult["https://foo.com"],
+      });
+      assert.equal(
+        feed.store.dispatch.secondCall.args[0].type,
+        at.DISCOVERY_STREAM_FEED_UPDATE
+      );
+      assert.deepEqual(feed.store.dispatch.secondCall.args[0].data, {
+        url: "https://bar.com",
+        feed: feedsTestResult["https://bar.com"],
+      });
+    });
+
+    it("should skip already personalized feeds", async () => {
+      sandbox.spy(feed, "scoreItems");
+      const recsExpireTime = 5600;
+      const fakeFeeds = {
+        data: {
+          "https://foo.com": {
+            personalized: true,
+            data: {
+              recommendations: [
+                {
+                  id: "first",
+                  item_score: 0.7,
+                },
+                {
+                  id: "second",
+                  item_score: 0.6,
+                },
+              ],
+              settings: {
+                recsExpireTime,
+              },
+            },
+          },
+        },
+      };
+
+      await feed.scoreFeeds(fakeFeeds);
+
+      assert.notCalled(feed.scoreItems);
+    });
+  });
+
+  describe("#scoreSpocs", () => {
+    beforeEach(() => {
+      sandbox.stub(feed.cache, "set").resolves();
+      sandbox.spy(feed.store, "dispatch");
+    });
+    it("should score spocs and set cache, dispatch", async () => {
+      const fakeDiscoveryStream = {
+        Prefs: {
+          values: {
+            "discoverystream.spocs.personalized": true,
+            "discoverystream.recs.personalized": false,
+          },
+        },
+        Personalization: {
+          initialized: true,
+        },
+        DiscoveryStream: {
+          spocs: {
+            placements: [
+              { name: "placement1" },
+              { name: "placement2" },
+              { name: "placement3" },
+            ],
+          },
+        },
+      };
+      sandbox.stub(feed.store, "getState").returns(fakeDiscoveryStream);
+      const fakeSpocs = {
+        lastUpdated: 1234,
+        data: {
+          placement1: {
+            items: [
+              {
+                item_score: 0.6,
+              },
+              {
+                item_score: 0.4,
+              },
+              {
+                item_score: 0.8,
+              },
+            ],
+          },
+          placement2: {
+            items: [
+              {
+                item_score: 0.6,
+              },
+              {
+                item_score: 0.8,
+              },
+            ],
+          },
+          placement3: { items: [] },
+        },
+      };
+
+      await feed.scoreSpocs(fakeSpocs);
+
+      const spocsTestResult = {
+        lastUpdated: 1234,
+        spocs: {
+          placement1: {
+            personalized: true,
+            items: [
+              {
+                score: 0.8,
+                item_score: 0.8,
+              },
+              {
+                score: 0.6,
+                item_score: 0.6,
+              },
+              {
+                score: 0.4,
+                item_score: 0.4,
+              },
+            ],
+          },
+          placement2: {
+            personalized: true,
+            items: [
+              {
+                score: 0.8,
+                item_score: 0.8,
+              },
+              {
+                score: 0.6,
+                item_score: 0.6,
+              },
+            ],
+          },
+          placement3: { items: [] },
+        },
+      };
+      assert.calledWith(feed.cache.set, "spocs", spocsTestResult);
+      assert.equal(
+        feed.store.dispatch.firstCall.args[0].type,
+        at.DISCOVERY_STREAM_SPOCS_UPDATE
+      );
+      assert.deepEqual(
+        feed.store.dispatch.firstCall.args[0].data,
+        spocsTestResult
+      );
+    });
+
+    it("should skip already personalized spocs", async () => {
+      sandbox.spy(feed, "scoreItems");
+      const fakeDiscoveryStream = {
+        Prefs: {
+          values: {
+            "discoverystream.spocs.personalized": true,
+            "discoverystream.recs.personalized": false,
+          },
+        },
+        Personalization: {
+          initialized: true,
+        },
+        DiscoveryStream: {
+          spocs: {
+            placements: [{ name: "placement1" }],
+          },
+        },
+      };
+      sandbox.stub(feed.store, "getState").returns(fakeDiscoveryStream);
+      const fakeSpocs = {
+        lastUpdated: 1234,
+        data: {
+          placement1: {
+            personalized: true,
+            items: [
+              {
+                item_score: 0.6,
+              },
+              {
+                item_score: 0.4,
+              },
+              {
+                item_score: 0.8,
+              },
+            ],
+          },
+        },
+      };
+
+      await feed.scoreSpocs(fakeSpocs);
+
+      assert.notCalled(feed.scoreItems);
+    });
+  });
+
+  describe("#onAction: DISCOVERY_STREAM_PERSONALIZATION_UPDATED", () => {
+    it("should call scoreFeeds and scoreSpocs if loaded", async () => {
+      const fakeDiscoveryStream = {
+        Prefs: {
+          values: {
+            pocketConfig: {
+              recsPersonalized: true,
+              spocsPersonalized: true,
+            },
+          },
+        },
+        DiscoveryStream: {
+          feeds: { loaded: false },
+          spocs: { loaded: false },
+        },
+      };
+
+      sandbox.stub(feed, "scoreFeeds").resolves();
+      sandbox.stub(feed, "scoreSpocs").resolves();
+      Object.defineProperty(feed, "personalized", { get: () => true });
+      sandbox.stub(feed.store, "getState").returns(fakeDiscoveryStream);
+
+      await feed.onAction({
+        type: at.DISCOVERY_STREAM_PERSONALIZATION_UPDATED,
+      });
+
+      assert.notCalled(feed.scoreFeeds);
+      assert.notCalled(feed.scoreSpocs);
+
+      fakeDiscoveryStream.DiscoveryStream.feeds.loaded = true;
+      fakeDiscoveryStream.DiscoveryStream.spocs.loaded = true;
+
+      await feed.onAction({
+        type: at.DISCOVERY_STREAM_PERSONALIZATION_UPDATED,
+      });
+
+      assert.calledOnce(feed.scoreFeeds);
+      assert.calledOnce(feed.scoreSpocs);
+    });
+  });
+
+  describe("#observe", () => {
+    it("should call configReset on Pocket button pref change", async () => {
+      sandbox.stub(feed, "configReset").returns();
+      feed.observe(null, "nsPref:changed", "extensions.pocket.enabled");
+      assert.calledOnce(feed.configReset);
+    });
+  });
+
+  describe("#scoreItem", () => {
+    it("should call calculateItemRelevanceScore with recommendationProvider with initial score", async () => {
+      const item = {
+        item_score: 0.6,
+      };
+      feed.recommendationProvider.store.getState = () => ({
+        Prefs: {
+          values: {
+            pocketConfig: {
+              recsPersonalized: true,
+              spocsPersonalized: true,
+            },
+            "discoverystream.personalization.enabled": true,
+            "feeds.section.topstories": true,
+            "feeds.system.topstories": true,
+          },
+        },
+      });
+      feed.recommendationProvider.calculateItemRelevanceScore = sandbox
+        .stub()
+        .returns();
+      const result = await feed.scoreItem(item, true);
+      assert.calledOnce(
+        feed.recommendationProvider.calculateItemRelevanceScore
+      );
+      assert.equal(result.score, 0.6);
+    });
+    it("should fallback to score 1 without an initial score", async () => {
+      const item = {};
+      feed.store.getState = () => ({
+        Prefs: {
+          values: {
+            "discoverystream.spocs.personalized": true,
+            "discoverystream.recs.personalized": true,
+            "discoverystream.personalization.enabled": true,
+          },
+        },
+      });
+      feed.recommendationProvider.calculateItemRelevanceScore = sandbox
+        .stub()
+        .returns();
+      const result = await feed.scoreItem(item, true);
+      assert.equal(result.score, 1);
+    });
+  });
+  describe("new proxy feed", () => {
+    beforeEach(() => {
+      feed.store = createStore(combineReducers(reducers), {
+        Prefs: {
+          values: {
+            pocketConfig: { regionBffConfig: "DE" },
+          },
+        },
+      });
+      sandbox.stub(global.Region, "home").get(() => "DE");
+      globals.set("NimbusFeatures", {
+        saveToPocket: {
+          getVariable: sandbox.stub(),
+        },
+      });
+      global.NimbusFeatures.saveToPocket.getVariable
+        .withArgs("bffApi")
+        .returns("bffApi");
+      global.NimbusFeatures.saveToPocket.getVariable
+        .withArgs("oAuthConsumerKeyBff")
+        .returns("oAuthConsumerKeyBff");
+    });
+    it("should return true with isBff", async () => {
+      assert.isUndefined(feed._isBff);
+      assert.isTrue(feed.isBff);
+      assert.isTrue(feed._isBff);
+    });
+    it("should update to new feed url", async () => {
+      await feed.loadLayout(feed.store.dispatch);
+      const { layout } = feed.store.getState().DiscoveryStream;
+      assert.equal(
+        layout[0].components[2].feed.url,
+        "https://bffApi/desktop/v1/recommendations?locale=$locale&region=$region&count=30"
+      );
+    });
+    it("should fetch proper data from getComponentFeed", async () => {
+      const fakeCache = {};
+      sandbox.stub(feed.cache, "get").returns(Promise.resolve(fakeCache));
+      sandbox.stub(feed, "rotate").callsFake(val => val);
+      sandbox
+        .stub(feed, "scoreItems")
+        .callsFake(val => ({ data: val, filtered: [], personalized: false }));
+      sandbox.stub(feed, "fetchFromEndpoint").resolves({
+        data: [
+          {
+            recommendationId: "decaf-c0ff33",
+            tileId: 1234,
+            url: "url",
+            title: "title",
+            excerpt: "excerpt",
+            publisher: "publisher",
+            timeToRead: "timeToRead",
+            imageUrl: "imageUrl",
+          },
+        ],
+      });
+
+      const feedData = await feed.getComponentFeed("url");
+      assert.deepEqual(feedData, {
+        lastUpdated: 0,
+        personalized: false,
+        data: {
+          settings: {},
+          recommendations: [
+            {
+              id: 1234,
+              url: "url",
+              title: "title",
+              excerpt: "excerpt",
+              publisher: "publisher",
+              time_to_read: "timeToRead",
+              raw_image_src: "imageUrl",
+              recommendation_id: "decaf-c0ff33",
+            },
+          ],
+          status: "success",
+        },
+      });
+      assert.equal(feed.fetchFromEndpoint.firstCall.args[0], "url");
+      assert.equal(feed.fetchFromEndpoint.firstCall.args[1].method, "GET");
+      assert.equal(
+        feed.fetchFromEndpoint.firstCall.args[1].headers.get("consumer_key"),
+        "oAuthConsumerKeyBff"
+      );
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/DownloadsManager.test.js b/browser/components/newtab/test/unit/lib/DownloadsManager.test.js
new file mode 100644
index 0000000000..ac262baf90
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/DownloadsManager.test.js
@@ -0,0 +1,373 @@
+import { actionTypes as at } from "common/Actions.sys.mjs";
+import { DownloadsManager } from "lib/DownloadsManager.sys.mjs";
+import { GlobalOverrider } from "test/unit/utils";
+
+describe("Downloads Manager", () => {
+  let downloadsManager;
+  let globals;
+  const DOWNLOAD_URL = "https://site.com/download.mov";
+
+  beforeEach(() => {
+    globals = new GlobalOverrider();
+    global.Cc["@mozilla.org/timer;1"] = {
+      createInstance() {
+        return {
+          initWithCallback: sinon.stub().callsFake(callback => callback()),
+          cancel: sinon.spy(),
+        };
+      },
+    };
+
+    globals.set("DownloadsCommon", {
+      getData: sinon.stub().returns({
+        addView: sinon.stub(),
+        removeView: sinon.stub(),
+      }),
+      copyDownloadLink: sinon.stub(),
+      deleteDownload: sinon.stub().returns(Promise.resolve()),
+      openDownload: sinon.stub(),
+      showDownloadedFile: sinon.stub(),
+    });
+
+    downloadsManager = new DownloadsManager();
+    downloadsManager.init({ dispatch() {} });
+    downloadsManager.onDownloadAdded({
+      source: { url: DOWNLOAD_URL },
+      endTime: Date.now(),
+      target: { path: "/path/to/download.mov", exists: true },
+      succeeded: true,
+      refresh: async () => {},
+    });
+    assert.ok(downloadsManager._downloadItems.has(DOWNLOAD_URL));
+
+    globals.set("NewTabUtils", { blockedLinks: { isBlocked() {} } });
+  });
+  afterEach(() => {
+    downloadsManager._downloadItems.clear();
+    globals.restore();
+  });
+  describe("#init", () => {
+    it("should add a DownloadsCommon view on init", () => {
+      downloadsManager.init({ dispatch() {} });
+      assert.calledTwice(global.DownloadsCommon.getData().addView);
+    });
+  });
+  describe("#onAction", () => {
+    it("should copy the file on COPY_DOWNLOAD_LINK", () => {
+      downloadsManager.onAction({
+        type: at.COPY_DOWNLOAD_LINK,
+        data: { url: DOWNLOAD_URL },
+      });
+      assert.calledOnce(global.DownloadsCommon.copyDownloadLink);
+    });
+    it("should remove the file on REMOVE_DOWNLOAD_FILE", () => {
+      downloadsManager.onAction({
+        type: at.REMOVE_DOWNLOAD_FILE,
+        data: { url: DOWNLOAD_URL },
+      });
+      assert.calledOnce(global.DownloadsCommon.deleteDownload);
+    });
+    it("should show the file on SHOW_DOWNLOAD_FILE", () => {
+      downloadsManager.onAction({
+        type: at.SHOW_DOWNLOAD_FILE,
+        data: { url: DOWNLOAD_URL },
+      });
+      assert.calledOnce(global.DownloadsCommon.showDownloadedFile);
+    });
+    it("should open the file on OPEN_DOWNLOAD_FILE if the type is download", () => {
+      downloadsManager.onAction({
+        type: at.OPEN_DOWNLOAD_FILE,
+        data: { url: DOWNLOAD_URL, type: "download" },
+        _target: { browser: {} },
+      });
+      assert.calledOnce(global.DownloadsCommon.openDownload);
+    });
+    it("should copy the file on UNINIT", () => {
+      // DownloadsManager._downloadData needs to exist first
+      downloadsManager.onAction({ type: at.UNINIT });
+      assert.calledOnce(global.DownloadsCommon.getData().removeView);
+    });
+    it("should not execute a download command if we do not have the correct url", () => {
+      downloadsManager.onAction({
+        type: at.SHOW_DOWNLOAD_FILE,
+        data: { url: "unknown_url" },
+      });
+      assert.notCalled(global.DownloadsCommon.showDownloadedFile);
+    });
+  });
+  describe("#onDownloadAdded", () => {
+    let newDownload;
+    beforeEach(() => {
+      downloadsManager._downloadItems.clear();
+      newDownload = {
+        source: { url: "https://site.com/newDownload.mov" },
+        endTime: Date.now(),
+        target: { path: "/path/to/newDownload.mov", exists: true },
+        succeeded: true,
+        refresh: async () => {},
+      };
+    });
+    afterEach(() => {
+      downloadsManager._downloadItems.clear();
+    });
+    it("should add a download on onDownloadAdded", () => {
+      downloadsManager.onDownloadAdded(newDownload);
+      assert.ok(
+        downloadsManager._downloadItems.has("https://site.com/newDownload.mov")
+      );
+    });
+    it("should not add a download if it already exists", () => {
+      downloadsManager.onDownloadAdded(newDownload);
+      downloadsManager.onDownloadAdded(newDownload);
+      downloadsManager.onDownloadAdded(newDownload);
+      downloadsManager.onDownloadAdded(newDownload);
+      const results = downloadsManager._downloadItems;
+      assert.equal(results.size, 1);
+    });
+    it("should not return any downloads if no threshold is provided", async () => {
+      downloadsManager.onDownloadAdded(newDownload);
+      const results = await downloadsManager.getDownloads(null, {});
+      assert.equal(results.length, 0);
+    });
+    it("should stop at numItems when it found one it's looking for", async () => {
+      const aDownload = {
+        source: { url: "https://site.com/aDownload.pdf" },
+        endTime: Date.now(),
+        target: { path: "/path/to/aDownload.pdf", exists: true },
+        succeeded: true,
+        refresh: async () => {},
+      };
+      downloadsManager.onDownloadAdded(aDownload);
+      downloadsManager.onDownloadAdded(newDownload);
+      const results = await downloadsManager.getDownloads(Infinity, {
+        numItems: 1,
+        onlySucceeded: true,
+        onlyExists: true,
+      });
+      assert.equal(results.length, 1);
+      assert.equal(results[0].url, aDownload.source.url);
+    });
+    it("should get all the downloads younger than the threshold provided", async () => {
+      const oldDownload = {
+        source: { url: "https://site.com/oldDownload.pdf" },
+        endTime: Date.now() - 40 * 60 * 60 * 1000,
+        target: { path: "/path/to/oldDownload.pdf", exists: true },
+        succeeded: true,
+        refresh: async () => {},
+      };
+      // Add an old download (older than 36 hours in this case)
+      downloadsManager.onDownloadAdded(oldDownload);
+      downloadsManager.onDownloadAdded(newDownload);
+      const RECENT_DOWNLOAD_THRESHOLD = 36 * 60 * 60 * 1000;
+      const results = await downloadsManager.getDownloads(
+        RECENT_DOWNLOAD_THRESHOLD,
+        { numItems: 5, onlySucceeded: true, onlyExists: true }
+      );
+      assert.equal(results.length, 1);
+      assert.equal(results[0].url, newDownload.source.url);
+    });
+    it("should dispatch DOWNLOAD_CHANGED when adding a download", () => {
+      downloadsManager._store.dispatch = sinon.spy();
+      downloadsManager._downloadTimer = null; // Nuke the timer
+      downloadsManager.onDownloadAdded(newDownload);
+      assert.calledOnce(downloadsManager._store.dispatch);
+    });
+    it("should refresh the downloads if onlyExists is true", async () => {
+      const aDownload = {
+        source: { url: "https://site.com/aDownload.pdf" },
+        endTime: Date.now() - 40 * 60 * 60 * 1000,
+        target: { path: "/path/to/aDownload.pdf", exists: true },
+        succeeded: true,
+        refresh: () => {},
+      };
+      sinon.stub(aDownload, "refresh").returns(Promise.resolve());
+      downloadsManager.onDownloadAdded(aDownload);
+      await downloadsManager.getDownloads(Infinity, {
+        numItems: 5,
+        onlySucceeded: true,
+        onlyExists: true,
+      });
+      assert.calledOnce(aDownload.refresh);
+    });
+    it("should not refresh the downloads if onlyExists is false (by default)", async () => {
+      const aDownload = {
+        source: { url: "https://site.com/aDownload.pdf" },
+        endTime: Date.now() - 40 * 60 * 60 * 1000,
+        target: { path: "/path/to/aDownload.pdf", exists: true },
+        succeeded: true,
+        refresh: () => {},
+      };
+      sinon.stub(aDownload, "refresh").returns(Promise.resolve());
+      downloadsManager.onDownloadAdded(aDownload);
+      await downloadsManager.getDownloads(Infinity, {
+        numItems: 5,
+        onlySucceeded: true,
+      });
+      assert.notCalled(aDownload.refresh);
+    });
+    it("should only return downloads that exist if specified", async () => {
+      const nonExistantDownload = {
+        source: { url: "https://site.com/nonExistantDownload.pdf" },
+        endTime: Date.now() - 40 * 60 * 60 * 1000,
+        target: { path: "/path/to/nonExistantDownload.pdf", exists: false },
+        succeeded: true,
+        refresh: async () => {},
+      };
+      downloadsManager.onDownloadAdded(newDownload);
+      downloadsManager.onDownloadAdded(nonExistantDownload);
+      const results = await downloadsManager.getDownloads(Infinity, {
+        numItems: 5,
+        onlySucceeded: true,
+        onlyExists: true,
+      });
+      assert.equal(results.length, 1);
+      assert.equal(results[0].url, newDownload.source.url);
+    });
+    it("should return all downloads that either exist or don't exist if not specified", async () => {
+      const nonExistantDownload = {
+        source: { url: "https://site.com/nonExistantDownload.pdf" },
+        endTime: Date.now() - 40 * 60 * 60 * 1000,
+        target: { path: "/path/to/nonExistantDownload.pdf", exists: false },
+        succeeded: true,
+        refresh: async () => {},
+      };
+      downloadsManager.onDownloadAdded(newDownload);
+      downloadsManager.onDownloadAdded(nonExistantDownload);
+      const results = await downloadsManager.getDownloads(Infinity, {
+        numItems: 5,
+        onlySucceeded: true,
+      });
+      assert.equal(results.length, 2);
+      assert.equal(results[0].url, newDownload.source.url);
+      assert.equal(results[1].url, nonExistantDownload.source.url);
+    });
+    it("should return only unblocked downloads", async () => {
+      const nonExistantDownload = {
+        source: { url: "https://site.com/nonExistantDownload.pdf" },
+        endTime: Date.now() - 40 * 60 * 60 * 1000,
+        target: { path: "/path/to/nonExistantDownload.pdf", exists: false },
+        succeeded: true,
+        refresh: async () => {},
+      };
+      downloadsManager.onDownloadAdded(newDownload);
+      downloadsManager.onDownloadAdded(nonExistantDownload);
+      globals.set("NewTabUtils", {
+        blockedLinks: {
+          isBlocked: item => item.url === nonExistantDownload.source.url,
+        },
+      });
+
+      const results = await downloadsManager.getDownloads(Infinity, {
+        numItems: 5,
+        onlySucceeded: true,
+      });
+
+      assert.equal(results.length, 1);
+      assert.propertyVal(results[0], "url", newDownload.source.url);
+    });
+    it("should only return downloads that were successful if specified", async () => {
+      const nonSuccessfulDownload = {
+        source: { url: "https://site.com/nonSuccessfulDownload.pdf" },
+        endTime: Date.now() - 40 * 60 * 60 * 1000,
+        target: { path: "/path/to/nonSuccessfulDownload.pdf", exists: false },
+        succeeded: false,
+        refresh: async () => {},
+      };
+      downloadsManager.onDownloadAdded(newDownload);
+      downloadsManager.onDownloadAdded(nonSuccessfulDownload);
+      const results = await downloadsManager.getDownloads(Infinity, {
+        numItems: 5,
+        onlySucceeded: true,
+      });
+      assert.equal(results.length, 1);
+      assert.equal(results[0].url, newDownload.source.url);
+    });
+    it("should return all downloads that were either successful or not if not specified", async () => {
+      const nonExistantDownload = {
+        source: { url: "https://site.com/nonExistantDownload.pdf" },
+        endTime: Date.now() - 40 * 60 * 60 * 1000,
+        target: { path: "/path/to/nonExistantDownload.pdf", exists: true },
+        succeeded: false,
+        refresh: async () => {},
+      };
+      downloadsManager.onDownloadAdded(newDownload);
+      downloadsManager.onDownloadAdded(nonExistantDownload);
+      const results = await downloadsManager.getDownloads(Infinity, {
+        numItems: 5,
+      });
+      assert.equal(results.length, 2);
+      assert.equal(results[0].url, newDownload.source.url);
+      assert.equal(results[1].url, nonExistantDownload.source.url);
+    });
+    it("should sort the downloads by recency", async () => {
+      const olderDownload1 = {
+        source: { url: "https://site.com/oldDownload1.pdf" },
+        endTime: Date.now() - 2 * 60 * 60 * 1000, // 2 hours ago
+        target: { path: "/path/to/oldDownload1.pdf", exists: true },
+        succeeded: true,
+        refresh: async () => {},
+      };
+      const olderDownload2 = {
+        source: { url: "https://site.com/oldDownload2.pdf" },
+        endTime: Date.now() - 60 * 60 * 1000, // 1 hour ago
+        target: { path: "/path/to/oldDownload2.pdf", exists: true },
+        succeeded: true,
+        refresh: async () => {},
+      };
+      // Add some older downloads and check that they are in order
+      downloadsManager.onDownloadAdded(olderDownload1);
+      downloadsManager.onDownloadAdded(olderDownload2);
+      downloadsManager.onDownloadAdded(newDownload);
+      const results = await downloadsManager.getDownloads(Infinity, {
+        numItems: 5,
+        onlySucceeded: true,
+        onlyExists: true,
+      });
+      assert.equal(results.length, 3);
+      assert.equal(results[0].url, newDownload.source.url);
+      assert.equal(results[1].url, olderDownload2.source.url);
+      assert.equal(results[2].url, olderDownload1.source.url);
+    });
+    it("should format the description properly if there is no file type", async () => {
+      newDownload.target.path = null;
+      downloadsManager.onDownloadAdded(newDownload);
+      const results = await downloadsManager.getDownloads(Infinity, {
+        numItems: 5,
+        onlySucceeded: true,
+        onlyExists: true,
+      });
+      assert.equal(results.length, 1);
+      assert.equal(results[0].description, "1.5 MB"); // see unit-entry.js to see where this comes from
+    });
+  });
+  describe("#onDownloadRemoved", () => {
+    let newDownload;
+    beforeEach(() => {
+      downloadsManager._downloadItems.clear();
+      newDownload = {
+        source: { url: "https://site.com/removeMe.mov" },
+        endTime: Date.now(),
+        target: { path: "/path/to/removeMe.mov", exists: true },
+        succeeded: true,
+        refresh: async () => {},
+      };
+      downloadsManager.onDownloadAdded(newDownload);
+    });
+    it("should remove a download if it exists on onDownloadRemoved", async () => {
+      downloadsManager.onDownloadRemoved({
+        source: { url: "https://site.com/removeMe.mov" },
+      });
+      const results = await downloadsManager.getDownloads(Infinity, {
+        numItems: 5,
+      });
+      assert.deepEqual(results, []);
+    });
+    it("should dispatch DOWNLOAD_CHANGED when removing a download", () => {
+      downloadsManager._store.dispatch = sinon.spy();
+      downloadsManager.onDownloadRemoved({
+        source: { url: "https://site.com/removeMe.mov" },
+      });
+      assert.calledOnce(downloadsManager._store.dispatch);
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/FaviconFeed.test.js b/browser/components/newtab/test/unit/lib/FaviconFeed.test.js
new file mode 100644
index 0000000000..e9be9b86ba
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/FaviconFeed.test.js
@@ -0,0 +1,233 @@
+"use strict";
+import { FaviconFeed, fetchIconFromRedirects } from "lib/FaviconFeed.sys.mjs";
+import { actionTypes as at } from "common/Actions.sys.mjs";
+import { GlobalOverrider } from "test/unit/utils";
+
+const FAKE_ENDPOINT = "https://foo.com/";
+
+describe("FaviconFeed", () => {
+  let feed;
+  let globals;
+  let sandbox;
+  let clock;
+  let siteIconsPref;
+
+  beforeEach(() => {
+    clock = sinon.useFakeTimers();
+    globals = new GlobalOverrider();
+    sandbox = globals.sandbox;
+    globals.set("PlacesUtils", {
+      favicons: {
+        setAndFetchFaviconForPage: sandbox.spy(),
+        getFaviconDataForPage: () => Promise.resolve(null),
+        FAVICON_LOAD_NON_PRIVATE: 1,
+      },
+      history: {
+        TRANSITIONS: {
+          REDIRECT_TEMPORARY: 1,
+          REDIRECT_PERMANENT: 2,
+        },
+      },
+    });
+    globals.set("NewTabUtils", {
+      activityStreamProvider: { executePlacesQuery: () => Promise.resolve([]) },
+    });
+    siteIconsPref = true;
+    sandbox
+      .stub(global.Services.prefs, "getBoolPref")
+      .withArgs("browser.chrome.site_icons")
+      .callsFake(() => siteIconsPref);
+
+    feed = new FaviconFeed();
+    feed.store = {
+      dispatch: sinon.spy(),
+      getState() {
+        return this.state;
+      },
+      state: {
+        Prefs: { values: { "tippyTop.service.endpoint": FAKE_ENDPOINT } },
+      },
+    };
+  });
+  afterEach(() => {
+    clock.restore();
+    globals.restore();
+  });
+
+  it("should create a FaviconFeed", () => {
+    assert.instanceOf(feed, FaviconFeed);
+  });
+
+  describe("#fetchIcon", () => {
+    let domain;
+    let url;
+    beforeEach(() => {
+      domain = "mozilla.org";
+      url = `https://${domain}/`;
+      feed.getSite = sandbox
+        .stub()
+        .returns(Promise.resolve({ domain, image_url: `${url}/icon.png` }));
+      feed._queryForRedirects.clear();
+    });
+
+    it("should setAndFetchFaviconForPage if the url is in the TippyTop data", async () => {
+      await feed.fetchIcon(url);
+
+      assert.calledOnce(global.PlacesUtils.favicons.setAndFetchFaviconForPage);
+      assert.calledWith(
+        global.PlacesUtils.favicons.setAndFetchFaviconForPage,
+        sinon.match({ spec: url }),
+        { ref: "tippytop", spec: `${url}/icon.png` },
+        false,
+        global.PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+        null,
+        undefined
+      );
+    });
+    it("should NOT setAndFetchFaviconForPage if site_icons pref is false", async () => {
+      siteIconsPref = false;
+
+      await feed.fetchIcon(url);
+
+      assert.notCalled(global.PlacesUtils.favicons.setAndFetchFaviconForPage);
+    });
+    it("should NOT setAndFetchFaviconForPage if the url is NOT in the TippyTop data", async () => {
+      feed.getSite = sandbox.stub().returns(Promise.resolve(null));
+      await feed.fetchIcon("https://example.com");
+
+      assert.notCalled(global.PlacesUtils.favicons.setAndFetchFaviconForPage);
+    });
+    it("should issue a fetchIconFromRedirects if the url is NOT in the TippyTop data", async () => {
+      feed.getSite = sandbox.stub().returns(Promise.resolve(null));
+      sandbox.spy(global.Services.tm, "idleDispatchToMainThread");
+
+      await feed.fetchIcon("https://example.com");
+
+      assert.calledOnce(global.Services.tm.idleDispatchToMainThread);
+    });
+    it("should only issue fetchIconFromRedirects once on the same url", async () => {
+      feed.getSite = sandbox.stub().returns(Promise.resolve(null));
+      sandbox.spy(global.Services.tm, "idleDispatchToMainThread");
+
+      await feed.fetchIcon("https://example.com");
+      await feed.fetchIcon("https://example.com");
+
+      assert.calledOnce(global.Services.tm.idleDispatchToMainThread);
+    });
+    it("should issue fetchIconFromRedirects twice on two different urls", async () => {
+      feed.getSite = sandbox.stub().returns(Promise.resolve(null));
+      sandbox.spy(global.Services.tm, "idleDispatchToMainThread");
+
+      await feed.fetchIcon("https://example.com");
+      await feed.fetchIcon("https://another.example.com");
+
+      assert.calledTwice(global.Services.tm.idleDispatchToMainThread);
+    });
+  });
+
+  describe("#getSite", () => {
+    it("should return site data if RemoteSettings has an entry for the domain", async () => {
+      const get = () =>
+        Promise.resolve([{ domain: "example.com", image_url: "foo.img" }]);
+      feed._tippyTop = { get };
+      const site = await feed.getSite("example.com");
+      assert.equal(site.domain, "example.com");
+    });
+    it("should return null if RemoteSettings doesn't have an entry for the domain", async () => {
+      const get = () => Promise.resolve([]);
+      feed._tippyTop = { get };
+      const site = await feed.getSite("example.com");
+      assert.isNull(site);
+    });
+    it("should lazy init _tippyTop", async () => {
+      assert.isUndefined(feed._tippyTop);
+      await feed.getSite("example.com");
+      assert.ok(feed._tippyTop);
+    });
+  });
+
+  describe("#onAction", () => {
+    it("should fetchIcon on RICH_ICON_MISSING", async () => {
+      feed.fetchIcon = sinon.spy();
+      const url = "https://mozilla.org";
+      feed.onAction({ type: at.RICH_ICON_MISSING, data: { url } });
+      assert.calledOnce(feed.fetchIcon);
+      assert.calledWith(feed.fetchIcon, url);
+    });
+  });
+
+  describe("#fetchIconFromRedirects", () => {
+    let domain;
+    let url;
+    let iconUrl;
+
+    beforeEach(() => {
+      domain = "mozilla.org";
+      url = `https://${domain}/`;
+      iconUrl = `${url}/icon.png`;
+    });
+    it("should setAndFetchFaviconForPage if the url was redirected with a icon", async () => {
+      sandbox
+        .stub(global.NewTabUtils.activityStreamProvider, "executePlacesQuery")
+        .resolves([
+          { visit_id: 1, url: domain },
+          { visit_id: 2, url },
+        ]);
+      sandbox
+        .stub(global.PlacesUtils.favicons, "getFaviconDataForPage")
+        .callsArgWith(1, { spec: iconUrl }, 0, null, null, 96);
+
+      await fetchIconFromRedirects(domain);
+
+      assert.calledOnce(global.PlacesUtils.favicons.setAndFetchFaviconForPage);
+      assert.calledWith(
+        global.PlacesUtils.favicons.setAndFetchFaviconForPage,
+        sinon.match({ spec: domain }),
+        { spec: iconUrl },
+        false,
+        global.PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+        null,
+        undefined
+      );
+    });
+    it("should NOT setAndFetchFaviconForPage if the url doesn't have any redirect", async () => {
+      sandbox
+        .stub(global.NewTabUtils.activityStreamProvider, "executePlacesQuery")
+        .resolves([]);
+
+      await fetchIconFromRedirects(domain);
+
+      assert.notCalled(global.PlacesUtils.favicons.setAndFetchFaviconForPage);
+    });
+    it("should NOT setAndFetchFaviconForPage if the original url doesn't have a icon", async () => {
+      sandbox
+        .stub(global.NewTabUtils.activityStreamProvider, "executePlacesQuery")
+        .resolves([
+          { visit_id: 1, url: domain },
+          { visit_id: 2, url },
+        ]);
+      sandbox
+        .stub(global.PlacesUtils.favicons, "getFaviconDataForPage")
+        .callsArgWith(1, null, null, null, null, null);
+
+      await fetchIconFromRedirects(domain);
+
+      assert.notCalled(global.PlacesUtils.favicons.setAndFetchFaviconForPage);
+    });
+    it("should NOT setAndFetchFaviconForPage if the original url doesn't have a rich icon", async () => {
+      sandbox
+        .stub(global.NewTabUtils.activityStreamProvider, "executePlacesQuery")
+        .resolves([
+          { visit_id: 1, url: domain },
+          { visit_id: 2, url },
+        ]);
+      sandbox
+        .stub(global.PlacesUtils.favicons, "getFaviconDataForPage")
+        .callsArgWith(1, { spec: iconUrl }, 0, null, null, 16);
+
+      await fetchIconFromRedirects(domain);
+
+      assert.notCalled(global.PlacesUtils.favicons.setAndFetchFaviconForPage);
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/FilterAdult.test.js b/browser/components/newtab/test/unit/lib/FilterAdult.test.js
new file mode 100644
index 0000000000..0e98a0d006
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/FilterAdult.test.js
@@ -0,0 +1,112 @@
+import { FilterAdult } from "lib/FilterAdult.sys.mjs";
+import { GlobalOverrider } from "test/unit/utils";
+
+describe("FilterAdult", () => {
+  let hashStub;
+  let hashValue;
+  let globals;
+
+  beforeEach(() => {
+    globals = new GlobalOverrider();
+    hashStub = {
+      finish: sinon.stub().callsFake(() => hashValue),
+      init: sinon.stub(),
+      update: sinon.stub(),
+    };
+    globals.set("Cc", {
+      "@mozilla.org/security/hash;1": {
+        createInstance() {
+          return hashStub;
+        },
+      },
+    });
+    globals.set("gFilterAdultEnabled", true);
+  });
+
+  afterEach(() => {
+    hashValue = "";
+    globals.restore();
+  });
+
+  describe("filter", () => {
+    it("should default to include on unexpected urls", () => {
+      const empty = {};
+
+      const result = FilterAdult.filter([empty]);
+
+      assert.equal(result.length, 1);
+      assert.equal(result[0], empty);
+    });
+    it("should not filter out non-adult urls", () => {
+      const link = { url: "https://mozilla.org/" };
+
+      const result = FilterAdult.filter([link]);
+
+      assert.equal(result.length, 1);
+      assert.equal(result[0], link);
+    });
+    it("should filter out adult urls", () => {
+      // Use a hash value that is in the adult set
+      hashValue = "+/UCpAhZhz368iGioEO8aQ==";
+      const link = { url: "https://some-adult-site/" };
+
+      const result = FilterAdult.filter([link]);
+
+      assert.equal(result.length, 0);
+    });
+    it("should not filter out adult urls if the preference is turned off", () => {
+      // Use a hash value that is in the adult set
+      hashValue = "+/UCpAhZhz368iGioEO8aQ==";
+      globals.set("gFilterAdultEnabled", false);
+      const link = { url: "https://some-adult-site/" };
+
+      const result = FilterAdult.filter([link]);
+
+      assert.equal(result.length, 1);
+      assert.equal(result[0], link);
+    });
+  });
+
+  describe("isAdultUrl", () => {
+    it("should default to false on unexpected urls", () => {
+      const result = FilterAdult.isAdultUrl("");
+
+      assert.equal(result, false);
+    });
+    it("should return false for non-adult urls", () => {
+      const result = FilterAdult.isAdultUrl("https://mozilla.org/");
+
+      assert.equal(result, false);
+    });
+    it("should return true for adult urls", () => {
+      // Use a hash value that is in the adult set
+      hashValue = "+/UCpAhZhz368iGioEO8aQ==";
+      const result = FilterAdult.isAdultUrl("https://some-adult-site/");
+
+      assert.equal(result, true);
+    });
+    it("should return false for adult urls when the preference is turned off", () => {
+      // Use a hash value that is in the adult set
+      hashValue = "+/UCpAhZhz368iGioEO8aQ==";
+      globals.set("gFilterAdultEnabled", false);
+      const result = FilterAdult.isAdultUrl("https://some-adult-site/");
+
+      assert.equal(result, false);
+    });
+
+    describe("test functions", () => {
+      it("should add and remove a filter in the adult list", () => {
+        // Use a hash value that is in the adult set
+        FilterAdult.addDomainToList("https://some-adult-site/");
+        let result = FilterAdult.isAdultUrl("https://some-adult-site/");
+
+        assert.equal(result, true);
+
+        FilterAdult.removeDomainFromList("https://some-adult-site/");
+        result = FilterAdult.isAdultUrl("https://some-adult-site/");
+
+        assert.equal(result, false);
+      });
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/LinksCache.test.js b/browser/components/newtab/test/unit/lib/LinksCache.test.js
new file mode 100644
index 0000000000..8a4d33d2f2
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/LinksCache.test.js
@@ -0,0 +1,16 @@
+import { LinksCache } from "lib/LinksCache.sys.mjs";
+
+describe("LinksCache", () => {
+  it("throws when failing request", async () => {
+    const cache = new LinksCache();
+
+    let rejected = false;
+    try {
+      await cache.request();
+    } catch (error) {
+      rejected = true;
+    }
+
+    assert(rejected);
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/NewTabInit.test.js b/browser/components/newtab/test/unit/lib/NewTabInit.test.js
new file mode 100644
index 0000000000..68ab9d7821
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/NewTabInit.test.js
@@ -0,0 +1,81 @@
+import {
+  actionCreators as ac,
+  actionTypes as at,
+} from "common/Actions.sys.mjs";
+import { NewTabInit } from "lib/NewTabInit.sys.mjs";
+
+describe("NewTabInit", () => {
+  let instance;
+  let store;
+  let STATE;
+  const requestFromTab = portID =>
+    instance.onAction(
+      ac.AlsoToMain({ type: at.NEW_TAB_STATE_REQUEST }, portID)
+    );
+  beforeEach(() => {
+    STATE = {};
+    store = { getState: sinon.stub().returns(STATE), dispatch: sinon.stub() };
+    instance = new NewTabInit();
+    instance.store = store;
+  });
+  it("should reply with a copy of the state immediately", () => {
+    requestFromTab(123);
+
+    const resp = ac.AlsoToOneContent(
+      { type: at.NEW_TAB_INITIAL_STATE, data: STATE },
+      123
+    );
+    assert.calledWith(store.dispatch, resp);
+  });
+  describe("early / simulated new tabs", () => {
+    const simulateTabInit = portID =>
+      instance.onAction({
+        type: at.NEW_TAB_INIT,
+        data: { portID, simulated: true },
+      });
+    beforeEach(() => {
+      simulateTabInit("foo");
+    });
+    it("should dispatch if not replied yet", () => {
+      requestFromTab("foo");
+
+      assert.calledWith(
+        store.dispatch,
+        ac.AlsoToOneContent(
+          { type: at.NEW_TAB_INITIAL_STATE, data: STATE },
+          "foo"
+        )
+      );
+    });
+    it("should dispatch once for multiple requests", () => {
+      requestFromTab("foo");
+      requestFromTab("foo");
+      requestFromTab("foo");
+
+      assert.calledOnce(store.dispatch);
+    });
+    describe("multiple tabs", () => {
+      beforeEach(() => {
+        simulateTabInit("bar");
+      });
+      it("should dispatch once to each tab", () => {
+        requestFromTab("foo");
+        requestFromTab("bar");
+        assert.calledTwice(store.dispatch);
+        requestFromTab("foo");
+        requestFromTab("bar");
+
+        assert.calledTwice(store.dispatch);
+      });
+      it("should clean up when tabs close", () => {
+        assert.propertyVal(instance._repliedEarlyTabs, "size", 2);
+        instance.onAction(ac.AlsoToMain({ type: at.NEW_TAB_UNLOAD }, "foo"));
+        assert.propertyVal(instance._repliedEarlyTabs, "size", 1);
+        instance.onAction(ac.AlsoToMain({ type: at.NEW_TAB_UNLOAD }, "foo"));
+        assert.propertyVal(instance._repliedEarlyTabs, "size", 1);
+        instance.onAction(ac.AlsoToMain({ type: at.NEW_TAB_UNLOAD }, "bar"));
+        assert.propertyVal(instance._repliedEarlyTabs, "size", 0);
+      });
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/PersistentCache.test.js b/browser/components/newtab/test/unit/lib/PersistentCache.test.js
new file mode 100644
index 0000000000..e645b8d398
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/PersistentCache.test.js
@@ -0,0 +1,142 @@
+import { GlobalOverrider } from "test/unit/utils";
+import { PersistentCache } from "lib/PersistentCache.sys.mjs";
+
+describe("PersistentCache", () => {
+  let fakeIOUtils;
+  let fakePathUtils;
+  let cache;
+  let filename = "cache.json";
+  let consoleErrorStub;
+  let globals;
+  let sandbox;
+
+  beforeEach(() => {
+    globals = new GlobalOverrider();
+    sandbox = sinon.createSandbox();
+    fakeIOUtils = {
+      writeJSON: sinon.stub().resolves(0),
+      readJSON: sinon.stub().resolves({}),
+    };
+    fakePathUtils = {
+      join: sinon.stub().returns(filename),
+      localProfileDir: "/",
+    };
+    consoleErrorStub = sandbox.stub();
+    globals.set("console", { error: consoleErrorStub });
+    globals.set("IOUtils", fakeIOUtils);
+    globals.set("PathUtils", fakePathUtils);
+
+    cache = new PersistentCache(filename);
+  });
+  afterEach(() => {
+    globals.restore();
+    sandbox.restore();
+  });
+
+  describe("#get", () => {
+    it("tries to read the file", async () => {
+      await cache.get("foo");
+      assert.calledOnce(fakeIOUtils.readJSON);
+    });
+    it("doesnt try to read the file if it was already loaded", async () => {
+      await cache._load();
+      fakeIOUtils.readJSON.resetHistory();
+      await cache.get("foo");
+      assert.notCalled(fakeIOUtils.readJSON);
+    });
+    it("should catch and report errors", async () => {
+      fakeIOUtils.readJSON.rejects(new SyntaxError("Failed to parse JSON"));
+      await cache._load();
+      assert.calledOnce(consoleErrorStub);
+
+      cache._cache = undefined;
+      consoleErrorStub.resetHistory();
+
+      fakeIOUtils.readJSON.rejects(
+        new DOMException("IOUtils shutting down", "AbortError")
+      );
+      await cache._load();
+      assert.calledOnce(consoleErrorStub);
+
+      cache._cache = undefined;
+      consoleErrorStub.resetHistory();
+
+      fakeIOUtils.readJSON.rejects(
+        new DOMException("File not found", "NotFoundError")
+      );
+      await cache._load();
+      assert.notCalled(consoleErrorStub);
+    });
+    it("returns data for a given cache key", async () => {
+      fakeIOUtils.readJSON.resolves({ foo: "bar" });
+      let value = await cache.get("foo");
+      assert.equal(value, "bar");
+    });
+    it("returns undefined for a cache key that doesn't exist", async () => {
+      let value = await cache.get("baz");
+      assert.equal(value, undefined);
+    });
+    it("returns all the data if no cache key is specified", async () => {
+      fakeIOUtils.readJSON.resolves({ foo: "bar" });
+      let value = await cache.get();
+      assert.deepEqual(value, { foo: "bar" });
+    });
+  });
+
+  describe("#set", () => {
+    it("tries to read the file on the first set", async () => {
+      await cache.set("foo", { x: 42 });
+      assert.calledOnce(fakeIOUtils.readJSON);
+    });
+    it("doesnt try to read the file if it was already loaded", async () => {
+      cache = new PersistentCache(filename, true);
+      await cache._load();
+      fakeIOUtils.readJSON.resetHistory();
+      await cache.set("foo", { x: 42 });
+      assert.notCalled(fakeIOUtils.readJSON);
+    });
+    it("sets a string value", async () => {
+      const key = "testkey";
+      const value = "testvalue";
+      await cache.set(key, value);
+      const cachedValue = await cache.get(key);
+      assert.equal(cachedValue, value);
+    });
+    it("sets an object value", async () => {
+      const key = "testkey";
+      const value = { x: 1, y: 2, z: 3 };
+      await cache.set(key, value);
+      const cachedValue = await cache.get(key);
+      assert.deepEqual(cachedValue, value);
+    });
+    it("writes the data to file", async () => {
+      const key = "testkey";
+      const value = { x: 1, y: 2, z: 3 };
+
+      await cache.set(key, value);
+      assert.calledOnce(fakeIOUtils.writeJSON);
+      assert.calledWith(
+        fakeIOUtils.writeJSON,
+        filename,
+        { [[key]]: value },
+        { tmpPath: `${filename}.tmp` }
+      );
+    });
+    it("throws when failing to get file path", async () => {
+      Object.defineProperty(fakePathUtils, "localProfileDir", {
+        get() {
+          throw new Error();
+        },
+      });
+
+      let rejected = false;
+      try {
+        await cache.set("key", "val");
+      } catch (error) {
+        rejected = true;
+      }
+
+      assert(rejected);
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/PersonalityProvider/NaiveBayesTextTagger.test.js b/browser/components/newtab/test/unit/lib/PersonalityProvider/NaiveBayesTextTagger.test.js
new file mode 100644
index 0000000000..18c634d43d
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/PersonalityProvider/NaiveBayesTextTagger.test.js
@@ -0,0 +1,95 @@
+import { NaiveBayesTextTagger } from "lib/PersonalityProvider/NaiveBayesTextTagger.mjs";
+import {
+  tokenize,
+  toksToTfIdfVector,
+} from "lib/PersonalityProvider/Tokenize.mjs";
+
+const EPSILON = 0.00001;
+
+describe("Naive Bayes Tagger", () => {
+  describe("#tag", () => {
+    let model = {
+      model_type: "nb",
+      positive_class_label: "military",
+      positive_class_id: 0,
+      positive_class_threshold_log_prob: -0.5108256237659907,
+      classes: [
+        {
+          log_prior: -0.6881346387364013,
+          feature_log_probs: [
+            -6.2149425847276, -6.829869141665873, -7.124856122235796,
+            -7.116661287797188, -6.694751331313906, -7.11798266787003,
+            -6.5094904366004185, -7.1639509366900604, -7.218981434452414,
+            -6.854842907887801, -7.080328841624584,
+          ],
+        },
+        {
+          log_prior: -0.6981849745899025,
+          feature_log_probs: [
+            -7.0575941199203465, -6.632333513597953, -7.382756370680115,
+            -7.1160793981275905, -8.467120918791892, -8.369201274990882,
+            -8.518506617006922, -7.015756380369387, -7.739036845511857,
+            -9.748294397894645, -3.9353548206941955,
+          ],
+        },
+      ],
+      vocab_idfs: {
+        deal: [0, 5.5058519847862275],
+        easy: [1, 5.5058519847862275],
+        tanks: [2, 5.601162164590552],
+        sites: [3, 5.957837108529285],
+        care: [4, 5.957837108529285],
+        needs: [5, 5.824305715904762],
+        finally: [6, 5.706522680248379],
+        super: [7, 5.264689927969339],
+        heard: [8, 5.5058519847862275],
+        reached: [9, 5.957837108529285],
+        words: [10, 5.070533913528382],
+      },
+    };
+    let instance = new NaiveBayesTextTagger(model, toksToTfIdfVector);
+
+    let testCases = [
+      {
+        input: "Finally! Super easy care for your tanks!",
+        expected: {
+          label: "military",
+          logProb: -0.16299510296630082,
+          confident: true,
+        },
+      },
+      {
+        input: "heard",
+        expected: {
+          label: "military",
+          logProb: -0.4628170738373294,
+          confident: false,
+        },
+      },
+      {
+        input: "words",
+        expected: {
+          label: null,
+          logProb: -0.04258339303757985,
+          confident: false,
+        },
+      },
+    ];
+
+    let checkTag = tc => {
+      let actual = instance.tagTokens(tokenize(tc.input));
+      it(`should tag ${tc.input} with ${tc.expected.label}`, () => {
+        assert.equal(tc.expected.label, actual.label);
+      });
+      it(`should give ${tc.input} the correct probability`, () => {
+        let delta = Math.abs(tc.expected.logProb - actual.logProb);
+        assert.isTrue(delta <= EPSILON);
+      });
+    };
+
+    // RELEASE THE TESTS!
+    for (let tc of testCases) {
+      checkTag(tc);
+    }
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/PersonalityProvider/NmfTextTagger.test.js b/browser/components/newtab/test/unit/lib/PersonalityProvider/NmfTextTagger.test.js
new file mode 100644
index 0000000000..aae070b305
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/PersonalityProvider/NmfTextTagger.test.js
@@ -0,0 +1,479 @@
+import { NmfTextTagger } from "lib/PersonalityProvider/NmfTextTagger.mjs";
+import {
+  tokenize,
+  toksToTfIdfVector,
+} from "lib/PersonalityProvider/Tokenize.mjs";
+
+const EPSILON = 0.00001;
+
+describe("NMF Tagger", () => {
+  describe("#tag", () => {
+    // The numbers in this model were pulled from existing trained model.
+    let model = {
+      document_topic: {
+        environment: [
+          0.05313956429537541, 0.07314019377743895, 0.03247190024863182,
+          0.016189529772591395, 0.003812317145412572, 0.03863075834647775,
+          0.007495425135831521, 0.005100298003919777, 0.005245622179405364,
+          0.036196010766427554, 0.02189970342121833, 0.03514130992119014,
+          0.001248114096050196, 0.0030908722594824665, 0.0023874256586350626,
+          0.008533674814792993, 0.0009424690250135675, 0.01603124888144218,
+          0.00752822798092765, 0.0039046678154748796, 0.03521776907836766,
+          0.00614546613169027, 0.0008272200196643818, 0.01405638079154697,
+          0.001990670259485496, 0.002803666919676377, 0.013841677883061631,
+          0.004093362693745272, 0.009310678536276432, 0.006158920150866703,
+          0.006821027337091937, 0.002712031105462971, 0.009093298611644996,
+          0.014642160500331744, 0.0067239941045715386, 0.007150418784462898,
+          0.0064652818600521265, 0.0006735690394489199, 0.02063188588742841,
+          0.003213083349614106, 0.0031998068360970093, 0.00264520606931871,
+          0.008854824468146531, 0.0024170562884908786, 0.0013705390639746128,
+          0.0030575940757273288, 0.010417378215688392, 0.002356164040132228,
+          0.0026710154645455007, 0.0007295327370144145, 0.0585307418954327,
+          0.0037987763460599574, 0.003199095437138493, 0.004368800434950577,
+          0.005087168372751965, 0.0011100904433965942, 0.01700096791869979,
+          0.01929226435023826, 0.010536397909643058, 0.001734999985783697,
+          0.003852807194017686, 0.007916805773686475, 0.028375307444815964,
+          0.0012422599635274355, 0.0009298594944844238, 0.02095410849846837,
+          0.0017269844428419192, 0.002152880993141985, 0.0030226616228192387,
+          0.004804812297400959, 0.0012383636748462198, 0.006991278216261148,
+          0.0013747035300597538, 0.002041541234639563, 0.012076270996247411,
+          0.006643837514421182, 0.003974012776560734, 0.015794539051705442,
+          0.007601190171659186, 0.016474925942594837, 0.002729423078513777,
+          0.007635146179880609, 0.013457547041824648, 0.0007592338429017099,
+          0.002947096673767141, 0.006371935735541048, 0.003356178481568716,
+          0.00451933490245723, 0.0019006306992329104, 0.013048046603391707,
+          0.023541628496101297, 0.027659066125377194, 0.002312727786055524,
+          0.0014189157259186062, 0.01963766030236683, 0.0026014761547439634,
+          0.002333697870992923, 0.003401734295211338, 0.002522073778255918,
+          0.0015769783084977752,
+        ],
+        space: [
+          0.045976774394786174, 0.04386532305052323, 0.03346748817597193,
+          0.008498345884036708, 0.005802390890667938, 0.0017673346473868704,
+          0.00468037374691276, 0.0036807899985757367, 0.0034951488381868424,
+          0.015073756869093244, 0.006784747891785806, 0.03069702365741547,
+          0.004945214461908244, 0.002527030239506901, 0.0012201743197690308,
+          0.010191409658936534, 0.0013882500616525532, 0.014559679471816162,
+          0.005308140956577744, 0.002067005832569046, 0.006092496689239475,
+          0.0029308442356851265, 0.0006407392160713908, 0.01669972147417425,
+          0.0018920321527190246, 0.002436089537269062, 0.05542174181989591,
+          0.006448761215865303, 0.012804154851567844, 0.014553974971946687,
+          0.004927456148063145, 0.006085620881900181, 0.011626122370522652,
+          0.002994267915422563, 0.0038291031528493898, 0.006987917175322377,
+          0.00719289436611732, 0.0008398926158042337, 0.019068654506361523,
+          0.004453895285397824, 0.00401164781243836, 0.0031309255764704544,
+          0.013210118660087334, 0.0015542151889036313, 0.0013951089590218057,
+          0.002790924761398501, 0.008739250167366135, 0.0027834569638271025,
+          0.09198161284531065, 0.0019488047187835441, 0.001739971582806101,
+          0.005113637251322287, 0.12140493794373561, 0.005535368890812829,
+          0.004198222617607059, 0.0010670629105233682, 0.005298717616708989,
+          0.0048291586850982855, 0.005140125537186181, 0.0011663683373124493,
+          0.0024499638218810943, 0.012532772497286819, 0.0015564613278042862,
+          0.0012252899339204029, 0.0005095187051357676, 0.0035442657060978655,
+          0.014030578705118285, 0.0017653534252553718, 0.004026729875153457,
+          0.004002067082856801, 0.00809773970333208, 0.017160384509220625,
+          0.002981945110677171, 0.0018338446554387704, 0.0031886913904107484,
+          0.004654622711785796, 0.0053886727821435415, 0.009023511029300392,
+          0.005246967669202147, 0.022806469628558337, 0.0035142224878495355,
+          0.006793295047927272, 0.017396620747821886, 0.000922278971300957,
+          0.001695889413253992, 0.007015197552957029, 0.003908581792868586,
+          0.010136260994789877, 0.0032880552208979508, 0.0039712539426523625,
+          0.009672046620728448, 0.007290428293346, 0.0017814796852793386,
+          0.0005388988974780036, 0.013936726486762537, 0.003427738251710856,
+          0.002206664729558829, 0.05072392472622557, 0.004424158921356747,
+          0.0003680061331891622,
+        ],
+        biology: [
+          0.054433533850037796, 0.039689474154513994, 0.027661000660240884,
+          0.021655563357213067, 0.007862624595639219, 0.006280655377019006,
+          0.013407714984668861, 0.004038592819712647, 0.009652765217013826,
+          0.0011353987945632667, 0.00925298156804724, 0.004870163054917538,
+          0.04911204317171355, 0.006921538451191124, 0.004003624507234068,
+          0.016600722822360296, 0.002179735905957767, 0.010801493818182368,
+          0.00918922860910538, 0.022115576350545514, 0.0027720850555002148,
+          0.003290714340925284, 0.0006359939927595049, 0.020564054347194806,
+          0.019590591011010666, 0.0029008397180383077, 0.030414664509122412,
+          0.002864704837438281, 0.030933936414333993, 0.00222576969791357,
+          0.007077232390623289, 0.005876547862506722, 0.016917705934608753,
+          0.016466207380001166, 0.006648808144677746, 0.017876914915160164,
+          0.008216930648675583, 0.0026813239798232098, 0.012171904585413245,
+          0.012319763594831614, 0.003909608203628946, 0.003205613981613637,
+          0.027729523430009183, 0.0019938396819227074, 0.002752482544417343,
+          0.0016746657427111145, 0.019564250521109314, 0.027250898086440583,
+          0.000954251437229793, 0.0020431321836649734, 0.0014636128217840221,
+          0.006821766389705783, 0.003272989792090916, 0.011086677363737012,
+          0.0044279892365732595, 0.0029213721398486203, 0.013081117655947345,
+          0.012102962176204816, 0.0029165848047082825, 0.002363073972325097,
+          0.0028567640089643695, 0.013692951578614878, 0.0013189478722657382,
+          0.0030662419379415885, 0.001688218039583749, 0.0007806438728749603,
+          0.025458033834110355, 0.009584308792578437, 0.0033243840056188263,
+          0.0068361098488461045, 0.005178034666939756, 0.006831575853694424,
+          0.010170774789130092, 0.004639315532453418, 0.00655511046953238,
+          0.005661100806175219, 0.006238755352678196, 0.023282136482285103,
+          0.007790828526461584, 0.011840304456780202, 0.0021953903460442225,
+          0.011205225479328193, 0.01665869590158306, 0.0009257333679666402,
+          0.0032380769616003604, 0.007379754534437712, 0.01804771060116468,
+          0.02540492978451049, 0.0027900782593570507, 0.0029721824342474694,
+          0.005666888959879564, 0.003629523931553047, 0.0017838703067849428,
+          0.004996486217852931, 0.006086510142627035, 0.0023570031997685236,
+          0.002718397814380002, 0.003908858478916721, 0.02080129902865465,
+          0.005591305783253238,
+        ],
+      },
+      topic_word: [
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.003173633134427233, 0.0, 0.0,
+          0.0019409914586816176, 0.0,
+        ],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 5.135548639746091e-5, 0.0, 0.0, 0.0,
+          0.00015384770766669982,
+        ],
+        [
+          0.0, 0.0, 0.0005001441880557176, 0.0, 0.0, 0.0012069823147301646,
+          0.02401141538644239, 8.831990149479376e-5, 0.001813504147854849, 0.0,
+        ],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.0003577161362340021, 0.0005744157863408606,
+          0.0, 0.0, 0.0,
+        ],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.002662246533243532, 0.0, 0.0,
+          0.0008394369973758684, 0.0,
+        ],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [
+          0.0, 4.768637450522633e-5, 0.0, 0.0, 0.0, 0.0, 0.0010421065429755969,
+          0.0, 0.0, 2.3210938729937306e-5,
+        ],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0006034363278588148,
+          0.001690622339085902, 0.0, 0.0,
+        ],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.004257728522853072, 0.0, 0.0, 0.0, 0.0],
+        [
+          0.0007238839225620208, 0.0, 0.0, 0.0, 0.0, 0.0009507496006759083,
+          0.0012635532859311572, 0.0, 0.0, 0.0,
+        ],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.2699264109324263e-5,
+          0.00032868342552128994, 0.0,
+        ],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0011157667743487598, 0.001278875789622101,
+          9.011724853181247e-6, 0.0, 3.22069766200917e-5, 0.004124963644732435,
+        ],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.00011961487736485771],
+        [0.0, 0.0, 0.0, 5.734703813314615e-5, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 4.0340264022466226e-5, 0.0, 0.0],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.00039701897786057513, 0.0, 0.0, 0.0, 0.0],
+        [
+          0.0, 0.0, 0.0, 0.19635202968946042, 0.0, 0.0008873887898279083, 0.0,
+          0.0, 0.0, 0.0,
+        ],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 1.552973162326247e-5, 0.0,
+          0.002284331845105356, 0.0, 0.0,
+        ],
+        [
+          0.0, 0.0, 0.005561738919282601, 0.0, 0.0, 0.0, 0.010700323065082812,
+          0.0, 0.0005795117202094265, 0.0,
+        ],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0005085828329663487, 0.0, 0.0, 0.0, 0.0],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.029261090049475084, 0.0020864946050332834,
+          0.0018513709831557076, 0.0, 0.0, 0.0,
+        ],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0008328286790309667, 0.0, 0.0, 0.0],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0013227647245223537, 0.0, 0.0, 0.0, 0.0],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0024010554774254685, 5.357245317969706e-5, 0.0,
+          0.0, 0.0, 0.0,
+        ],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0014484032312145462, 0.0],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0012081428144960678, 0.0, 0.0, 0.0, 0.0],
+        [
+          0.0, 0.0, 0.000616488580813398, 0.0, 0.0, 0.0017954524796671627, 0.0,
+          0.0, 0.0, 0.0,
+        ],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0006660554263924299, 0.0, 0.0, 0.0, 0.0],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0011891151421092303, 0.0, 0.0],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.0024885434472066534, 0.0,
+          0.0010165824086743897, 0.0, 0.0,
+        ],
+        [
+          0.0, 5.692292246819767e-5, 0.0, 0.0, 0.001006289633741549, 0.0, 0.0,
+          0.001897882990870404, 0.0, 0.0,
+        ],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.00010646854330751878, 0.0,
+          0.0013480243353754932, 0.0,
+        ],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0002608785715957589, 0.0],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.0010620422134845085, 0.0, 0.0,
+          0.0002032215308376943, 0.0,
+        ],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.0008928062238389307, 0.0, 0.0,
+          5.727265080002417e-5, 0.0,
+        ],
+        [
+          0.0, 0.0, 0.06061253593083364, 0.0, 0.02739898181912798, 0.0, 0.0,
+          0.0, 0.0, 0.0,
+        ],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0014338134220455178, 0.0,
+          0.0011276871850520397, 0.002840121913315777,
+        ],
+        [0.0008014293374641945, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [
+          0.0, 0.000345858724152025, 0.013078498367906305, 0.0,
+          0.002815596608197659, 0.0, 0.0, 0.0030778986683343023, 0.0, 0.0,
+        ],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0010177321509216356, 0.0, 0.0, 0.0, 0.0],
+        [0.0, 0.0, 0.0, 0.0, 0.00015333347872060042, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0009655934464519347, 0.0],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.0008542046515290346, 0.0, 0.0,
+          0.00016472517230317488, 0.0,
+        ],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0007759590139787148,
+          0.0037535348789227703, 0.0007205740927611773,
+        ],
+        [
+          0.0, 0.0, 0.0010313963595627862, 0.0, 0.0, 0.0, 0.0, 0.0,
+          0.0069665132800572115, 0.0,
+        ],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.0006880323929924655, 9.207429290830475e-5,
+          0.0, 0.0, 0.0,
+        ],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0008404475484102756, 0.0, 0.0, 0.0, 0.0],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.00016603822882009137, 0.0, 0.0, 0.0,
+          0.0004386724451378034,
+        ],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.003971386830918022, 0.0, 0.0, 0.0, 0.0],
+        [0.000983926199078037, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.001299108775819868, 0.0, 0.0, 0.0, 0.0],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [
+          0.16326515307916822, 0.0, 0.0, 0.0, 0.0, 0.0028677496385613155,
+          0.023677620702293598, 0.0, 0.0, 0.0,
+        ],
+        [0.0, 0.0, 5.737710913345495e-6, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [
+          0.0, 0.0, 0.0002081792662367579, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0,
+          0.0002840163488982256,
+        ],
+        [0.0, 0.0, 0.0, 0.0, 0.0005021534925351664, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.001057424953719077, 0.0,
+          0.003578658690485632, 0.0, 0.0,
+        ],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.00022950619982206556,
+          0.0018791783657735252, 0.0008530683004027156, 4.5513911743540586e-5,
+          0.0,
+        ],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0045523319463242765, 0.0, 0.0, 0.0, 0.0],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0006160628426134845, 0.0, 0.0023393152617350653,
+          0.0, 0.0, 0.0012979890699731222,
+        ],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [
+          0.0, 0.0, 0.003391399407584813, 0.0, 0.0, 0.000719659722017165, 0.0,
+          0.004722518573572638, 0.002758841738663124, 0.0,
+        ],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.002127862313876461, 0.0, 0.005031998155190167,
+          0.0, 0.0, 0.0,
+        ],
+        [
+          0.0, 0.0, 0.00055401373160389, 0.0, 0.0, 0.000333325450244618,
+          0.0017824446558959168, 0.0011398506826041158, 0.0,
+          0.0006366915431430632,
+        ],
+        [
+          0.0, 0.21687336139378274, 0.0, 0.0, 0.0, 0.0030345303266644387, 0.0,
+          0.0, 0.0, 0.0,
+        ],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.0012637173523723526, 0.0,
+          0.0010158476831041915, 0.0035425832276585615, 0.0,
+        ],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.0015451984659512325, 0.019909953764629045,
+          0.0013484737840911303, 0.0033472098053086113, 0.0016951819626954759,
+        ],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.00015923419851654453, 0.0,
+          0.0024056492047359367,
+        ],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.01305313280419075,
+          0.00014197157780982973, 0.0, 0.0,
+        ],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.000746430999979358, 0.0,
+          0.0010041202546700189, 0.004557016648181857, 0.0,
+        ],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.00021372865758801545,
+          0.00025925151316940747, 0.0,
+        ],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.001658746582791234, 0.0],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.00973640859923001, 0.0012404719999980969,
+          0.0006365355864806626, 0.0008291013715577852, 0.0, 0.0,
+        ],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.001473459191608214, 0.0, 0.0,
+          0.0009195459918865811, 0.002012929485852207,
+        ],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0005850456523130979, 0.0,
+          0.00014396718214395852, 0.0,
+        ],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0011858302272740567, 0.0],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0046803403116507545, 0.002083219444498354, 0.0,
+          0.0, 0.0, 0.006104495765365948,
+        ],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.005456944646675863, 0.0,
+          0.00011428354610339084, 0.0, 0.0,
+        ],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0013384597578988894, 0.0, 0.0, 0.0, 0.0],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.0018450592044551373, 0.0,
+          0.005182965872305058, 0.0, 0.0,
+        ],
+        [
+          0.0, 0.0, 0.0, 0.0, 0.0, 0.0003041074021307749, 0.0,
+          0.0020827735275448823, 0.0, 0.0008494429669380388,
+        ],
+        [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+      ],
+      vocab_idfs: {
+        blood: [0, 5.0948820521571045],
+        earth: [1, 4.2248041634380815],
+        rocket: [2, 5.666668375712782],
+        brain: [3, 4.616846251214104],
+        mars: [4, 6.226284163648205],
+        nothing: [5, 5.270772718620769],
+        nada: [6, 4.815297189937943],
+        star: [7, 6.38880309314598],
+        zilch: [8, 5.889811927026992],
+        soil: [9, 7.14257489552236],
+      },
+    };
+
+    let instance = new NmfTextTagger(model, toksToTfIdfVector);
+
+    let testCases = [
+      {
+        input: "blood is in the brain",
+        expected: {
+          environment: 0.00037336337061919943,
+          space: 0.0003307690554984028,
+          biology: 0.0026549079818439627,
+        },
+      },
+
+      {
+        input: "rocket to the star",
+        expected: {
+          environment: 0.0002855180592590448,
+          space: 0.004006242743506598,
+          biology: 0.0003094182371360131,
+        },
+      },
+      {
+        input: "rocket to the star mars",
+        expected: {
+          environment: 0.0004180326651780644,
+          space: 0.003844259295376754,
+          biology: 0.0003135623817729136,
+        },
+      },
+      {
+        input: "rocket rocket rocket",
+        expected: {
+          environment: 0.00033052002469507015,
+          space: 0.007519787053895712,
+          biology: 0.00031862864995569246,
+        },
+      },
+      {
+        input: "nothing nada rocket",
+        expected: {
+          environment: 0.0008597524218029812,
+          space: 0.0035401031629944506,
+          biology: 0.000950627767326667,
+        },
+      },
+      {
+        input: "rocket",
+        expected: {
+          environment: 0.00033052002469507015,
+          space: 0.007519787053895712,
+          biology: 0.00031862864995569246,
+        },
+      },
+      {
+        input: "this sentence is out of vocabulary",
+        expected: {
+          environment: 0.0,
+          space: 0.0,
+          biology: 0.0,
+        },
+      },
+      {
+        input: "this sentence is out of vocabulary except for rocket",
+        expected: {
+          environment: 0.00033052002469507015,
+          space: 0.007519787053895712,
+          biology: 0.00031862864995569246,
+        },
+      },
+    ];
+
+    let checkTag = tc => {
+      let actual = instance.tagTokens(tokenize(tc.input));
+      it(`should score ${tc.input} correctly`, () => {
+        Object.keys(actual).forEach(tag => {
+          let delta = Math.abs(tc.expected[tag] - actual[tag]);
+          assert.isTrue(delta <= EPSILON);
+        });
+      });
+    };
+
+    // RELEASE THE TESTS!
+    for (let tc of testCases) {
+      checkTag(tc);
+    }
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/PersonalityProvider/PersonalityProvider.test.js b/browser/components/newtab/test/unit/lib/PersonalityProvider/PersonalityProvider.test.js
new file mode 100644
index 0000000000..0058fd7c76
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/PersonalityProvider/PersonalityProvider.test.js
@@ -0,0 +1,356 @@
+import { GlobalOverrider } from "test/unit/utils";
+import { PersonalityProvider } from "lib/PersonalityProvider/PersonalityProvider.sys.mjs";
+
+describe("Personality Provider", () => {
+  let instance;
+  let RemoteSettingsStub;
+  let RemoteSettingsOnStub;
+  let RemoteSettingsOffStub;
+  let RemoteSettingsGetStub;
+  let sandbox;
+  let globals;
+  let baseURLStub;
+
+  beforeEach(() => {
+    sandbox = sinon.createSandbox();
+    globals = new GlobalOverrider();
+
+    RemoteSettingsOnStub = sandbox.stub().returns();
+    RemoteSettingsOffStub = sandbox.stub().returns();
+    RemoteSettingsGetStub = sandbox.stub().returns([]);
+
+    RemoteSettingsStub = name => ({
+      get: RemoteSettingsGetStub,
+      on: RemoteSettingsOnStub,
+      off: RemoteSettingsOffStub,
+    });
+
+    sinon.spy(global, "BasePromiseWorker");
+    sinon.spy(global.BasePromiseWorker.prototype, "post");
+
+    baseURLStub = "https://baseattachmentsurl";
+    global.fetch = async server => ({
+      ok: true,
+      json: async () => {
+        if (server === "bogus://foo/") {
+          return { capabilities: { attachments: { base_url: baseURLStub } } };
+        }
+        return {};
+      },
+    });
+    globals.set("RemoteSettings", RemoteSettingsStub);
+
+    instance = new PersonalityProvider();
+    instance.interestConfig = {
+      history_item_builder: "history_item_builder",
+      history_required_fields: ["a", "b", "c"],
+      interest_finalizer: "interest_finalizer",
+      item_to_rank_builder: "item_to_rank_builder",
+      item_ranker: "item_ranker",
+      interest_combiner: "interest_combiner",
+    };
+  });
+  afterEach(() => {
+    sinon.restore();
+    sandbox.restore();
+    globals.restore();
+  });
+  describe("#personalityProviderWorker", () => {
+    it("should create a new promise worker on first call", async () => {
+      const { personalityProviderWorker } = instance;
+      assert.calledOnce(global.BasePromiseWorker);
+      assert.isDefined(personalityProviderWorker);
+    });
+    it("should cache _personalityProviderWorker on first call", async () => {
+      instance._personalityProviderWorker = null;
+      const { personalityProviderWorker } = instance;
+      assert.isDefined(instance._personalityProviderWorker);
+      assert.isDefined(personalityProviderWorker);
+    });
+    it("should use old promise worker on second call", async () => {
+      let { personalityProviderWorker } = instance;
+      personalityProviderWorker = instance.personalityProviderWorker;
+      assert.calledOnce(global.BasePromiseWorker);
+      assert.isDefined(personalityProviderWorker);
+    });
+  });
+  describe("#_getBaseAttachmentsURL", () => {
+    it("should return a fresh value", async () => {
+      await instance._getBaseAttachmentsURL();
+      assert.equal(instance._baseAttachmentsURL, baseURLStub);
+    });
+    it("should return a cached value", async () => {
+      const cachedURL = "cached";
+      instance._baseAttachmentsURL = cachedURL;
+      await instance._getBaseAttachmentsURL();
+      assert.equal(instance._baseAttachmentsURL, cachedURL);
+    });
+  });
+  describe("#setup", () => {
+    it("should setup two sync attachments", () => {
+      sinon.spy(instance, "setupSyncAttachment");
+      instance.setup();
+      assert.calledTwice(instance.setupSyncAttachment);
+    });
+  });
+  describe("#teardown", () => {
+    it("should teardown two sync attachments", () => {
+      sinon.spy(instance, "teardownSyncAttachment");
+      instance.teardown();
+      assert.calledTwice(instance.teardownSyncAttachment);
+    });
+    it("should terminate worker", () => {
+      const terminateStub = sandbox.stub().returns();
+      instance._personalityProviderWorker = {
+        terminate: terminateStub,
+      };
+      instance.teardown();
+      assert.calledOnce(terminateStub);
+    });
+  });
+  describe("#setupSyncAttachment", () => {
+    it("should call remote settings on twice for setupSyncAttachment", () => {
+      assert.calledTwice(RemoteSettingsOnStub);
+    });
+  });
+  describe("#teardownSyncAttachment", () => {
+    it("should call remote settings off for teardownSyncAttachment", () => {
+      instance.teardownSyncAttachment();
+      assert.calledOnce(RemoteSettingsOffStub);
+    });
+  });
+  describe("#onSync", () => {
+    it("should call worker onSync", () => {
+      instance.onSync();
+      assert.calledWith(global.BasePromiseWorker.prototype.post, "onSync");
+    });
+  });
+  describe("#getAttachment", () => {
+    it("should call worker onSync", () => {
+      instance.getAttachment();
+      assert.calledWith(
+        global.BasePromiseWorker.prototype.post,
+        "getAttachment"
+      );
+    });
+  });
+  describe("#getRecipe", () => {
+    it("should call worker getRecipe and remote settings get", async () => {
+      RemoteSettingsGetStub = sandbox.stub().returns([
+        {
+          key: 1,
+        },
+      ]);
+      sinon.spy(instance, "getAttachment");
+      RemoteSettingsStub = name => ({
+        get: RemoteSettingsGetStub,
+        on: RemoteSettingsOnStub,
+        off: RemoteSettingsOffStub,
+      });
+      globals.set("RemoteSettings", RemoteSettingsStub);
+
+      const result = await instance.getRecipe();
+      assert.calledOnce(RemoteSettingsGetStub);
+      assert.calledOnce(instance.getAttachment);
+      assert.equal(result.recordKey, 1);
+    });
+  });
+  describe("#fetchHistory", () => {
+    it("should return a history object for fetchHistory", async () => {
+      const history = await instance.fetchHistory(["requiredColumn"], 1, 1);
+      assert.equal(
+        history.sql,
+        `SELECT url, title, visit_count, frecency, last_visit_date, description\n    FROM moz_places\n    WHERE last_visit_date >= 1000000\n    AND last_visit_date < 1000000 AND IFNULL(requiredColumn, '') <> '' LIMIT 30000`
+      );
+      assert.equal(history.options.columns.length, 1);
+      assert.equal(Object.keys(history.options.params).length, 0);
+    });
+  });
+  describe("#getHistory", () => {
+    it("should return an empty array", async () => {
+      instance.interestConfig = {
+        history_required_fields: [],
+      };
+      const result = await instance.getHistory();
+      assert.equal(result.length, 0);
+    });
+    it("should call fetchHistory", async () => {
+      sinon.spy(instance, "fetchHistory");
+      await instance.getHistory();
+    });
+  });
+  describe("#setBaseAttachmentsURL", () => {
+    it("should call worker setBaseAttachmentsURL", async () => {
+      await instance.setBaseAttachmentsURL();
+      assert.calledWith(
+        global.BasePromiseWorker.prototype.post,
+        "setBaseAttachmentsURL"
+      );
+    });
+  });
+  describe("#setInterestConfig", () => {
+    it("should call worker setInterestConfig", async () => {
+      await instance.setInterestConfig();
+      assert.calledWith(
+        global.BasePromiseWorker.prototype.post,
+        "setInterestConfig"
+      );
+    });
+  });
+  describe("#setInterestVector", () => {
+    it("should call worker setInterestVector", async () => {
+      await instance.setInterestVector();
+      assert.calledWith(
+        global.BasePromiseWorker.prototype.post,
+        "setInterestVector"
+      );
+    });
+  });
+  describe("#fetchModels", () => {
+    it("should call worker fetchModels and remote settings get", async () => {
+      await instance.fetchModels();
+      assert.calledOnce(RemoteSettingsGetStub);
+      assert.calledWith(global.BasePromiseWorker.prototype.post, "fetchModels");
+    });
+  });
+  describe("#generateTaggers", () => {
+    it("should call worker generateTaggers", async () => {
+      await instance.generateTaggers();
+      assert.calledWith(
+        global.BasePromiseWorker.prototype.post,
+        "generateTaggers"
+      );
+    });
+  });
+  describe("#generateRecipeExecutor", () => {
+    it("should call worker generateRecipeExecutor", async () => {
+      await instance.generateRecipeExecutor();
+      assert.calledWith(
+        global.BasePromiseWorker.prototype.post,
+        "generateRecipeExecutor"
+      );
+    });
+  });
+  describe("#createInterestVector", () => {
+    it("should call worker createInterestVector", async () => {
+      await instance.createInterestVector();
+      assert.calledWith(
+        global.BasePromiseWorker.prototype.post,
+        "createInterestVector"
+      );
+    });
+  });
+  describe("#init", () => {
+    it("should return early if setInterestConfig fails", async () => {
+      sandbox.stub(instance, "setBaseAttachmentsURL").returns();
+      sandbox.stub(instance, "setInterestConfig").returns();
+      instance.interestConfig = null;
+      const callback = globals.sandbox.stub();
+      await instance.init(callback);
+      assert.notCalled(callback);
+    });
+    it("should return early if fetchModels fails", async () => {
+      sandbox.stub(instance, "setBaseAttachmentsURL").returns();
+      sandbox.stub(instance, "setInterestConfig").returns();
+      sandbox.stub(instance, "fetchModels").resolves({
+        ok: false,
+      });
+      const callback = globals.sandbox.stub();
+      await instance.init(callback);
+      assert.notCalled(callback);
+    });
+    it("should return early if createInterestVector fails", async () => {
+      sandbox.stub(instance, "setBaseAttachmentsURL").returns();
+      sandbox.stub(instance, "setInterestConfig").returns();
+      sandbox.stub(instance, "fetchModels").resolves({
+        ok: true,
+      });
+      sandbox.stub(instance, "generateRecipeExecutor").resolves({
+        ok: true,
+      });
+      sandbox.stub(instance, "createInterestVector").resolves({
+        ok: false,
+      });
+      const callback = globals.sandbox.stub();
+      await instance.init(callback);
+      assert.notCalled(callback);
+    });
+    it("should call callback on successful init", async () => {
+      sandbox.stub(instance, "setBaseAttachmentsURL").returns();
+      sandbox.stub(instance, "setInterestConfig").returns();
+      sandbox.stub(instance, "fetchModels").resolves({
+        ok: true,
+      });
+      sandbox.stub(instance, "generateRecipeExecutor").resolves({
+        ok: true,
+      });
+      sandbox.stub(instance, "createInterestVector").resolves({
+        ok: true,
+      });
+      sandbox.stub(instance, "setInterestVector").resolves();
+      const callback = globals.sandbox.stub();
+      await instance.init(callback);
+      assert.calledOnce(callback);
+      assert.isTrue(instance.initialized);
+    });
+    it("should do generic init stuff when calling init with no cache", async () => {
+      sandbox.stub(instance, "setBaseAttachmentsURL").returns();
+      sandbox.stub(instance, "setInterestConfig").returns();
+      sandbox.stub(instance, "fetchModels").resolves({
+        ok: true,
+      });
+      sandbox.stub(instance, "generateRecipeExecutor").resolves({
+        ok: true,
+      });
+      sandbox.stub(instance, "createInterestVector").resolves({
+        ok: true,
+        interestVector: "interestVector",
+      });
+      sandbox.stub(instance, "setInterestVector").resolves();
+      await instance.init();
+      assert.calledOnce(instance.setBaseAttachmentsURL);
+      assert.calledOnce(instance.setInterestConfig);
+      assert.calledOnce(instance.fetchModels);
+      assert.calledOnce(instance.generateRecipeExecutor);
+      assert.calledOnce(instance.createInterestVector);
+      assert.calledOnce(instance.setInterestVector);
+    });
+  });
+  describe("#calculateItemRelevanceScore", () => {
+    it("should return score for uninitialized provider", async () => {
+      instance.initialized = false;
+      assert.equal(
+        await instance.calculateItemRelevanceScore({ item_score: 2 }),
+        2
+      );
+    });
+    it("should return score for initialized provider", async () => {
+      instance.initialized = true;
+
+      instance._personalityProviderWorker = {
+        post: (postName, [item]) => ({
+          rankingVector: { score: item.item_score },
+        }),
+      };
+
+      assert.equal(
+        await instance.calculateItemRelevanceScore({ item_score: 2 }),
+        2
+      );
+    });
+    it("should post calculateItemRelevanceScore to PersonalityProviderWorker", async () => {
+      instance.initialized = true;
+      await instance.calculateItemRelevanceScore({ item_score: 2 });
+      assert.calledWith(
+        global.BasePromiseWorker.prototype.post,
+        "calculateItemRelevanceScore"
+      );
+    });
+  });
+  describe("#getScores", () => {
+    it("should return correct data for getScores", () => {
+      const scores = instance.getScores();
+      assert.isDefined(scores.interestConfig);
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/PersonalityProvider/PersonalityProviderWorkerClass.test.js b/browser/components/newtab/test/unit/lib/PersonalityProvider/PersonalityProviderWorkerClass.test.js
new file mode 100644
index 0000000000..da6454c6d6
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/PersonalityProvider/PersonalityProviderWorkerClass.test.js
@@ -0,0 +1,456 @@
+import { GlobalOverrider } from "test/unit/utils";
+import { PersonalityProviderWorker } from "lib/PersonalityProvider/PersonalityProviderWorkerClass.mjs";
+import {
+  tokenize,
+  toksToTfIdfVector,
+} from "lib/PersonalityProvider/Tokenize.mjs";
+import { RecipeExecutor } from "lib/PersonalityProvider/RecipeExecutor.mjs";
+import { NmfTextTagger } from "lib/PersonalityProvider/NmfTextTagger.mjs";
+import { NaiveBayesTextTagger } from "lib/PersonalityProvider/NaiveBayesTextTagger.mjs";
+
+describe("Personality Provider Worker Class", () => {
+  let instance;
+  let globals;
+  let sandbox;
+
+  beforeEach(() => {
+    sandbox = sinon.createSandbox();
+    globals = new GlobalOverrider();
+    globals.set("tokenize", tokenize);
+    globals.set("toksToTfIdfVector", toksToTfIdfVector);
+    globals.set("NaiveBayesTextTagger", NaiveBayesTextTagger);
+    globals.set("NmfTextTagger", NmfTextTagger);
+    globals.set("RecipeExecutor", RecipeExecutor);
+    instance = new PersonalityProviderWorker();
+
+    // mock the RecipeExecutor
+    instance.recipeExecutor = {
+      executeRecipe: (item, recipe) => {
+        if (recipe === "history_item_builder") {
+          if (item.title === "fail") {
+            return null;
+          }
+          return {
+            title: item.title,
+            score: item.frecency,
+            type: "history_item",
+          };
+        } else if (recipe === "interest_finalizer") {
+          return {
+            title: item.title,
+            score: item.score * 100,
+            type: "interest_vector",
+          };
+        } else if (recipe === "item_to_rank_builder") {
+          if (item.title === "fail") {
+            return null;
+          }
+          return {
+            item_title: item.title,
+            item_score: item.score,
+            type: "item_to_rank",
+          };
+        } else if (recipe === "item_ranker") {
+          if (item.title === "fail" || item.item_title === "fail") {
+            return null;
+          }
+          return {
+            title: item.title,
+            score: item.item_score * item.score,
+            type: "ranked_item",
+          };
+        }
+        return null;
+      },
+      executeCombinerRecipe: (item1, item2, recipe) => {
+        if (recipe === "interest_combiner") {
+          if (
+            item1.title === "combiner_fail" ||
+            item2.title === "combiner_fail"
+          ) {
+            return null;
+          }
+          if (item1.type === undefined) {
+            item1.type = "combined_iv";
+          }
+          if (item1.score === undefined) {
+            item1.score = 0;
+          }
+          return { type: item1.type, score: item1.score + item2.score };
+        }
+        return null;
+      },
+    };
+
+    instance.interestConfig = {
+      history_item_builder: "history_item_builder",
+      history_required_fields: ["a", "b", "c"],
+      interest_finalizer: "interest_finalizer",
+      item_to_rank_builder: "item_to_rank_builder",
+      item_ranker: "item_ranker",
+      interest_combiner: "interest_combiner",
+    };
+  });
+  afterEach(() => {
+    sinon.restore();
+    sandbox.restore();
+    globals.restore();
+  });
+  describe("#setBaseAttachmentsURL", () => {
+    it("should set baseAttachmentsURL", () => {
+      instance.setBaseAttachmentsURL("url");
+      assert.equal(instance.baseAttachmentsURL, "url");
+    });
+  });
+  describe("#setInterestConfig", () => {
+    it("should set interestConfig", () => {
+      instance.setInterestConfig("config");
+      assert.equal(instance.interestConfig, "config");
+    });
+  });
+  describe("#setInterestVector", () => {
+    it("should set interestVector", () => {
+      instance.setInterestVector("vector");
+      assert.equal(instance.interestVector, "vector");
+    });
+  });
+  describe("#onSync", async () => {
+    it("should sync remote settings collection from onSync", async () => {
+      sinon.stub(instance, "deleteAttachment").resolves();
+      sinon.stub(instance, "maybeDownloadAttachment").resolves();
+
+      instance.onSync({
+        data: {
+          created: ["create-1", "create-2"],
+          updated: [
+            { old: "update-old-1", new: "update-new-1" },
+            { old: "update-old-2", new: "update-new-2" },
+          ],
+          deleted: ["delete-2", "delete-1"],
+        },
+      });
+
+      assert(instance.maybeDownloadAttachment.withArgs("create-1").calledOnce);
+      assert(instance.maybeDownloadAttachment.withArgs("create-2").calledOnce);
+      assert(
+        instance.maybeDownloadAttachment.withArgs("update-new-1").calledOnce
+      );
+      assert(
+        instance.maybeDownloadAttachment.withArgs("update-new-2").calledOnce
+      );
+
+      assert(instance.deleteAttachment.withArgs("delete-1").calledOnce);
+      assert(instance.deleteAttachment.withArgs("delete-2").calledOnce);
+      assert(instance.deleteAttachment.withArgs("update-old-1").calledOnce);
+      assert(instance.deleteAttachment.withArgs("update-old-2").calledOnce);
+    });
+  });
+  describe("#maybeDownloadAttachment", () => {
+    it("should attempt _downloadAttachment three times for maybeDownloadAttachment", async () => {
+      let existsStub;
+      let statStub;
+      let attachmentStub;
+      sinon.stub(instance, "_downloadAttachment").resolves();
+      const makeDirStub = globals.sandbox
+        .stub(global.IOUtils, "makeDirectory")
+        .resolves();
+
+      existsStub = globals.sandbox
+        .stub(global.IOUtils, "exists")
+        .resolves(true);
+
+      statStub = globals.sandbox
+        .stub(global.IOUtils, "stat")
+        .resolves({ size: "1" });
+
+      attachmentStub = {
+        attachment: {
+          filename: "file",
+          size: "1",
+          // This hash matches the hash generated from the empty Uint8Array returned by the IOUtils.read stub.
+          hash: "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+        },
+      };
+
+      await instance.maybeDownloadAttachment(attachmentStub);
+      assert.calledWith(makeDirStub, "personality-provider");
+      assert.calledOnce(existsStub);
+      assert.calledOnce(statStub);
+      assert.notCalled(instance._downloadAttachment);
+
+      existsStub.resetHistory();
+      statStub.resetHistory();
+      instance._downloadAttachment.resetHistory();
+
+      attachmentStub = {
+        attachment: {
+          filename: "file",
+          size: "2",
+        },
+      };
+
+      await instance.maybeDownloadAttachment(attachmentStub);
+      assert.calledThrice(existsStub);
+      assert.calledThrice(statStub);
+      assert.calledThrice(instance._downloadAttachment);
+
+      existsStub.resetHistory();
+      statStub.resetHistory();
+      instance._downloadAttachment.resetHistory();
+
+      attachmentStub = {
+        attachment: {
+          filename: "file",
+          size: "1",
+          // Bogus hash to trigger an update.
+          hash: "1234",
+        },
+      };
+
+      await instance.maybeDownloadAttachment(attachmentStub);
+      assert.calledThrice(existsStub);
+      assert.calledThrice(statStub);
+      assert.calledThrice(instance._downloadAttachment);
+    });
+  });
+  describe("#_downloadAttachment", () => {
+    beforeEach(() => {
+      globals.set("Uint8Array", class Uint8Array {});
+    });
+    it("should write a file from _downloadAttachment", async () => {
+      globals.set(
+        "XMLHttpRequest",
+        class {
+          constructor() {
+            this.status = 200;
+            this.response = "response!";
+          }
+          open() {}
+          setRequestHeader() {}
+          send() {}
+        }
+      );
+
+      const ioutilsWriteStub = globals.sandbox
+        .stub(global.IOUtils, "write")
+        .resolves();
+
+      await instance._downloadAttachment({
+        attachment: { location: "location", filename: "filename" },
+      });
+
+      const writeArgs = ioutilsWriteStub.firstCall.args;
+      assert.equal(writeArgs[0], "filename");
+      assert.equal(writeArgs[2].tmpPath, "filename.tmp");
+    });
+    it("should call console.error from _downloadAttachment if not valid response", async () => {
+      globals.set(
+        "XMLHttpRequest",
+        class {
+          constructor() {
+            this.status = 0;
+            this.response = "response!";
+          }
+          open() {}
+          setRequestHeader() {}
+          send() {}
+        }
+      );
+
+      const consoleErrorStub = globals.sandbox
+        .stub(console, "error")
+        .resolves();
+
+      await instance._downloadAttachment({
+        attachment: { location: "location", filename: "filename" },
+      });
+
+      assert.calledOnce(consoleErrorStub);
+    });
+  });
+  describe("#deleteAttachment", () => {
+    it("should remove attachments when calling deleteAttachment", async () => {
+      const makeDirStub = globals.sandbox
+        .stub(global.IOUtils, "makeDirectory")
+        .resolves();
+      const removeStub = globals.sandbox
+        .stub(global.IOUtils, "remove")
+        .resolves();
+      await instance.deleteAttachment({ attachment: { filename: "filename" } });
+      assert.calledOnce(makeDirStub);
+      assert.calledTwice(removeStub);
+      assert.calledWith(removeStub.firstCall, "filename", {
+        ignoreAbsent: true,
+      });
+      assert.calledWith(removeStub.secondCall, "personality-provider", {
+        ignoreAbsent: true,
+      });
+    });
+  });
+  describe("#getAttachment", () => {
+    it("should return JSON when calling getAttachment", async () => {
+      sinon.stub(instance, "maybeDownloadAttachment").resolves();
+      const readJSONStub = globals.sandbox
+        .stub(global.IOUtils, "readJSON")
+        .resolves({});
+      const record = { attachment: { filename: "filename" } };
+      let returnValue = await instance.getAttachment(record);
+
+      assert.calledOnce(readJSONStub);
+      assert.calledWith(readJSONStub, "filename");
+      assert.calledOnce(instance.maybeDownloadAttachment);
+      assert.calledWith(instance.maybeDownloadAttachment, record);
+      assert.deepEqual(returnValue, {});
+
+      readJSONStub.restore();
+      globals.sandbox.stub(global.IOUtils, "readJSON").throws("foo");
+      const consoleErrorStub = globals.sandbox
+        .stub(console, "error")
+        .resolves();
+      returnValue = await instance.getAttachment(record);
+
+      assert.calledOnce(consoleErrorStub);
+      assert.deepEqual(returnValue, {});
+    });
+  });
+  describe("#fetchModels", () => {
+    it("should return ok true", async () => {
+      sinon.stub(instance, "getAttachment").resolves();
+      const result = await instance.fetchModels([{ key: 1234 }]);
+      assert.isTrue(result.ok);
+      assert.deepEqual(instance.models, [{ recordKey: 1234 }]);
+    });
+    it("should return ok false", async () => {
+      sinon.stub(instance, "getAttachment").resolves();
+      const result = await instance.fetchModels([]);
+      assert.isTrue(!result.ok);
+    });
+  });
+  describe("#generateTaggers", () => {
+    it("should generate taggers from modelKeys", () => {
+      const modelKeys = ["nb_model_sports", "nmf_model_sports"];
+
+      instance.models = [
+        { recordKey: "nb_model_sports", model_type: "nb" },
+        {
+          recordKey: "nmf_model_sports",
+          model_type: "nmf",
+          parent_tag: "nmf_sports_parent_tag",
+        },
+      ];
+
+      instance.generateTaggers(modelKeys);
+      assert.equal(instance.taggers.nbTaggers.length, 1);
+      assert.equal(Object.keys(instance.taggers.nmfTaggers).length, 1);
+    });
+    it("should skip any models not in modelKeys", () => {
+      const modelKeys = ["nb_model_sports"];
+
+      instance.models = [
+        { recordKey: "nb_model_sports", model_type: "nb" },
+        {
+          recordKey: "nmf_model_sports",
+          model_type: "nmf",
+          parent_tag: "nmf_sports_parent_tag",
+        },
+      ];
+
+      instance.generateTaggers(modelKeys);
+      assert.equal(instance.taggers.nbTaggers.length, 1);
+      assert.equal(Object.keys(instance.taggers.nmfTaggers).length, 0);
+    });
+    it("should skip any models not defined", () => {
+      const modelKeys = ["nb_model_sports", "nmf_model_sports"];
+
+      instance.models = [{ recordKey: "nb_model_sports", model_type: "nb" }];
+      instance.generateTaggers(modelKeys);
+      assert.equal(instance.taggers.nbTaggers.length, 1);
+      assert.equal(Object.keys(instance.taggers.nmfTaggers).length, 0);
+    });
+  });
+  describe("#generateRecipeExecutor", () => {
+    it("should generate a recipeExecutor", () => {
+      instance.recipeExecutor = null;
+      instance.taggers = {};
+      instance.generateRecipeExecutor();
+      assert.isNotNull(instance.recipeExecutor);
+    });
+  });
+  describe("#createInterestVector", () => {
+    let mockHistory = [];
+    beforeEach(() => {
+      mockHistory = [
+        {
+          title: "automotive",
+          description: "something about automotive",
+          url: "http://example.com/automotive",
+          frecency: 10,
+        },
+        {
+          title: "fashion",
+          description: "something about fashion",
+          url: "http://example.com/fashion",
+          frecency: 5,
+        },
+        {
+          title: "tech",
+          description: "something about tech",
+          url: "http://example.com/tech",
+          frecency: 1,
+        },
+      ];
+    });
+    it("should gracefully handle history entries that fail", () => {
+      mockHistory.push({ title: "fail" });
+      assert.isNotNull(instance.createInterestVector(mockHistory));
+    });
+
+    it("should fail if the combiner fails", () => {
+      mockHistory.push({ title: "combiner_fail", frecency: 111 });
+      let actual = instance.createInterestVector(mockHistory);
+      assert.isNull(actual);
+    });
+
+    it("should process history, combine, and finalize", () => {
+      let actual = instance.createInterestVector(mockHistory);
+      assert.equal(actual.interestVector.score, 1600);
+    });
+  });
+  describe("#calculateItemRelevanceScore", () => {
+    it("should return null for busted item", () => {
+      assert.equal(
+        instance.calculateItemRelevanceScore({ title: "fail" }),
+        null
+      );
+    });
+    it("should return null for a busted ranking", () => {
+      instance.interestVector = { title: "fail", score: 10 };
+      assert.equal(
+        instance.calculateItemRelevanceScore({ title: "some item", score: 6 }),
+        null
+      );
+    });
+    it("should return a score, and not change with interestVector", () => {
+      instance.interestVector = { score: 10 };
+      assert.equal(
+        instance.calculateItemRelevanceScore({ score: 2 }).rankingVector.score,
+        20
+      );
+      assert.deepEqual(instance.interestVector, { score: 10 });
+    });
+    it("should use defined personalization_models if available", () => {
+      instance.interestVector = { score: 10 };
+      const item = {
+        score: 2,
+        personalization_models: {
+          entertainment: 1,
+        },
+      };
+      assert.equal(
+        instance.calculateItemRelevanceScore(item).scorableItem.item_tags
+          .entertainment,
+        1
+      );
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/PersonalityProvider/RecipeExecutor.test.js b/browser/components/newtab/test/unit/lib/PersonalityProvider/RecipeExecutor.test.js
new file mode 100644
index 0000000000..fdbcae9613
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/PersonalityProvider/RecipeExecutor.test.js
@@ -0,0 +1,1543 @@
+import { RecipeExecutor } from "lib/PersonalityProvider/RecipeExecutor.mjs";
+import { tokenize } from "lib/PersonalityProvider/Tokenize.mjs";
+
+class MockTagger {
+  constructor(mode, tagScoreMap) {
+    this.mode = mode;
+    this.tagScoreMap = tagScoreMap;
+  }
+  tagTokens(tokens) {
+    if (this.mode === "nb") {
+      // eslint-disable-next-line prefer-destructuring
+      let tag = Object.keys(this.tagScoreMap)[0];
+      // eslint-disable-next-line prefer-destructuring
+      let prob = this.tagScoreMap[tag];
+      let conf = prob >= 0.85;
+      return {
+        label: tag,
+        logProb: Math.log(prob),
+        confident: conf,
+      };
+    }
+    return this.tagScoreMap;
+  }
+  tag(text) {
+    return this.tagTokens([text]);
+  }
+}
+
+describe("RecipeExecutor", () => {
+  let makeItem = () => {
+    let x = {
+      lhs: 2,
+      one: 1,
+      two: 2,
+      three: 3,
+      foo: "FOO",
+      bar: "BAR",
+      baz: ["one", "two", "three"],
+      qux: 42,
+      text: "This Is A_sentence.",
+      url: "http://www.wonder.example.com/dir1/dir2a-dir2b/dir3+4?key1&key2=val2&key3&%26amp=%3D3+4",
+      url2: "http://wonder.example.com/dir1/dir2a-dir2b/dir3+4?key1&key2=val2&key3&%26amp=%3D3+4",
+      map: {
+        c: 3,
+        a: 1,
+        b: 2,
+      },
+      map2: {
+        b: 2,
+        c: 3,
+        d: 4,
+      },
+      arr1: [2, 3, 4],
+      arr2: [3, 4, 5],
+      long: [3, 4, 5, 6, 7],
+      tags: {
+        a: {
+          aa: 0.1,
+          ab: 0.2,
+          ac: 0.3,
+        },
+        b: {
+          ba: 4,
+          bb: 5,
+          bc: 6,
+        },
+      },
+      bogus: {
+        a: {
+          aa: "0.1",
+          ab: "0.2",
+          ac: "0.3",
+        },
+        b: {
+          ba: "4",
+          bb: "5",
+          bc: "6",
+        },
+      },
+      zero: {
+        a: 0,
+        b: 0,
+      },
+      zaro: [0, 0],
+    };
+    return x;
+  };
+
+  let EPSILON = 0.00001;
+
+  let instance = new RecipeExecutor(
+    [
+      new MockTagger("nb", { tag1: 0.7 }),
+      new MockTagger("nb", { tag2: 0.86 }),
+      new MockTagger("nb", { tag3: 0.9 }),
+      new MockTagger("nb", { tag5: 0.9 }),
+    ],
+    {
+      tag1: new MockTagger("nmf", {
+        tag11: 0.9,
+        tag12: 0.8,
+        tag13: 0.7,
+      }),
+      tag2: new MockTagger("nmf", {
+        tag21: 0.8,
+        tag22: 0.7,
+        tag23: 0.6,
+      }),
+      tag3: new MockTagger("nmf", {
+        tag31: 0.7,
+        tag32: 0.6,
+        tag33: 0.5,
+      }),
+      tag4: new MockTagger("nmf", { tag41: 0.99 }),
+    },
+    tokenize
+  );
+  let item = null;
+
+  beforeEach(() => {
+    item = makeItem();
+  });
+
+  describe("#_assembleText", () => {
+    it("should simply copy a single string", () => {
+      assert.equal(instance._assembleText(item, ["foo"]), "FOO");
+    });
+    it("should append some strings with a space", () => {
+      assert.equal(instance._assembleText(item, ["foo", "bar"]), "FOO BAR");
+    });
+    it("should give an empty string for a missing field", () => {
+      assert.equal(instance._assembleText(item, ["missing"]), "");
+    });
+    it("should not double space an interior missing field", () => {
+      assert.equal(
+        instance._assembleText(item, ["foo", "missing", "bar"]),
+        "FOO BAR"
+      );
+    });
+    it("should splice in an array of strings", () => {
+      assert.equal(
+        instance._assembleText(item, ["foo", "baz", "bar"]),
+        "FOO one two three BAR"
+      );
+    });
+    it("should handle numbers", () => {
+      assert.equal(
+        instance._assembleText(item, ["foo", "qux", "bar"]),
+        "FOO 42 BAR"
+      );
+    });
+  });
+
+  describe("#naiveBayesTag", () => {
+    it("should understand NaiveBayesTextTagger", () => {
+      item = instance.naiveBayesTag(item, { fields: ["text"] });
+      assert.isTrue("nb_tags" in item);
+      assert.isTrue(!("tag1" in item.nb_tags));
+      assert.equal(item.nb_tags.tag2, 0.86);
+      assert.equal(item.nb_tags.tag3, 0.9);
+      assert.equal(item.nb_tags.tag5, 0.9);
+      assert.isTrue("nb_tokens" in item);
+      assert.deepEqual(item.nb_tokens, ["this", "is", "a", "sentence"]);
+      assert.isTrue("nb_tags_extended" in item);
+      assert.isTrue(!("tag1" in item.nb_tags_extended));
+      assert.deepEqual(item.nb_tags_extended.tag2, {
+        label: "tag2",
+        logProb: Math.log(0.86),
+        confident: true,
+      });
+      assert.deepEqual(item.nb_tags_extended.tag3, {
+        label: "tag3",
+        logProb: Math.log(0.9),
+        confident: true,
+      });
+      assert.deepEqual(item.nb_tags_extended.tag5, {
+        label: "tag5",
+        logProb: Math.log(0.9),
+        confident: true,
+      });
+      assert.isTrue("nb_tokens" in item);
+      assert.deepEqual(item.nb_tokens, ["this", "is", "a", "sentence"]);
+    });
+  });
+
+  describe("#conditionallyNmfTag", () => {
+    it("should do nothing if it's not nb tagged", () => {
+      item = instance.conditionallyNmfTag(item, {});
+      assert.equal(item, null);
+    });
+    it("should populate nmf tags for the nb tags", () => {
+      item = instance.naiveBayesTag(item, { fields: ["text"] });
+      item = instance.conditionallyNmfTag(item, {});
+      assert.isTrue("nb_tags" in item);
+      assert.deepEqual(item.nmf_tags, {
+        tag2: {
+          tag21: 0.8,
+          tag22: 0.7,
+          tag23: 0.6,
+        },
+        tag3: {
+          tag31: 0.7,
+          tag32: 0.6,
+          tag33: 0.5,
+        },
+      });
+      assert.deepEqual(item.nmf_tags_parent, {
+        tag21: "tag2",
+        tag22: "tag2",
+        tag23: "tag2",
+        tag31: "tag3",
+        tag32: "tag3",
+        tag33: "tag3",
+      });
+    });
+    it("should not populate nmf tags for things that were not nb tagged", () => {
+      item = instance.naiveBayesTag(item, { fields: ["text"] });
+      item = instance.conditionallyNmfTag(item, {});
+      assert.isTrue("nmf_tags" in item);
+      assert.isTrue(!("tag4" in item.nmf_tags));
+      assert.isTrue("nmf_tags_parent" in item);
+      assert.isTrue(!("tag4" in item.nmf_tags_parent));
+    });
+  });
+
+  describe("#acceptItemByFieldValue", () => {
+    it("should implement ==", () => {
+      assert.isTrue(
+        instance.acceptItemByFieldValue(item, {
+          field: "lhs",
+          op: "==",
+          rhsValue: 2,
+        }) !== null
+      );
+      assert.isTrue(
+        instance.acceptItemByFieldValue(item, {
+          field: "lhs",
+          op: "==",
+          rhsValue: 3,
+        }) === null
+      );
+      assert.isTrue(
+        instance.acceptItemByFieldValue(item, {
+          field: "lhs",
+          op: "==",
+          rhsField: "two",
+        }) !== null
+      );
+      assert.isTrue(
+        instance.acceptItemByFieldValue(item, {
+          field: "lhs",
+          op: "==",
+          rhsField: "three",
+        }) === null
+      );
+    });
+    it("should implement !=", () => {
+      assert.isTrue(
+        instance.acceptItemByFieldValue(item, {
+          field: "lhs",
+          op: "!=",
+          rhsValue: 2,
+        }) === null
+      );
+      assert.isTrue(
+        instance.acceptItemByFieldValue(item, {
+          field: "lhs",
+          op: "!=",
+          rhsValue: 3,
+        }) !== null
+      );
+    });
+    it("should implement < ", () => {
+      assert.isTrue(
+        instance.acceptItemByFieldValue(item, {
+          field: "lhs",
+          op: "<",
+          rhsValue: 1,
+        }) === null
+      );
+      assert.isTrue(
+        instance.acceptItemByFieldValue(item, {
+          field: "lhs",
+          op: "<",
+          rhsValue: 2,
+        }) === null
+      );
+      assert.isTrue(
+        instance.acceptItemByFieldValue(item, {
+          field: "lhs",
+          op: "<",
+          rhsValue: 3,
+        }) !== null
+      );
+    });
+    it("should implement <= ", () => {
+      assert.isTrue(
+        instance.acceptItemByFieldValue(item, {
+          field: "lhs",
+          op: "<=",
+          rhsValue: 1,
+        }) === null
+      );
+      assert.isTrue(
+        instance.acceptItemByFieldValue(item, {
+          field: "lhs",
+          op: "<=",
+          rhsValue: 2,
+        }) !== null
+      );
+      assert.isTrue(
+        instance.acceptItemByFieldValue(item, {
+          field: "lhs",
+          op: "<=",
+          rhsValue: 3,
+        }) !== null
+      );
+    });
+    it("should implement > ", () => {
+      assert.isTrue(
+        instance.acceptItemByFieldValue(item, {
+          field: "lhs",
+          op: ">",
+          rhsValue: 1,
+        }) !== null
+      );
+      assert.isTrue(
+        instance.acceptItemByFieldValue(item, {
+          field: "lhs",
+          op: ">",
+          rhsValue: 2,
+        }) === null
+      );
+      assert.isTrue(
+        instance.acceptItemByFieldValue(item, {
+          field: "lhs",
+          op: ">",
+          rhsValue: 3,
+        }) === null
+      );
+    });
+    it("should implement >= ", () => {
+      assert.isTrue(
+        instance.acceptItemByFieldValue(item, {
+          field: "lhs",
+          op: ">=",
+          rhsValue: 1,
+        }) !== null
+      );
+      assert.isTrue(
+        instance.acceptItemByFieldValue(item, {
+          field: "lhs",
+          op: ">=",
+          rhsValue: 2,
+        }) !== null
+      );
+      assert.isTrue(
+        instance.acceptItemByFieldValue(item, {
+          field: "lhs",
+          op: ">=",
+          rhsValue: 3,
+        }) === null
+      );
+    });
+    it("should skip items with missing fields", () => {
+      assert.isTrue(
+        instance.acceptItemByFieldValue(item, {
+          field: "no-left",
+          op: "==",
+          rhsValue: 1,
+        }) === null
+      );
+      assert.isTrue(
+        instance.acceptItemByFieldValue(item, {
+          field: "lhs",
+          op: "==",
+          rhsField: "no-right",
+        }) === null
+      );
+      assert.isTrue(
+        instance.acceptItemByFieldValue(item, { field: "lhs", op: "==" }) ===
+          null
+      );
+    });
+    it("should skip items with bogus operators", () => {
+      assert.isTrue(
+        instance.acceptItemByFieldValue(item, {
+          field: "lhs",
+          op: "bogus",
+          rhsField: "two",
+        }) === null
+      );
+    });
+  });
+
+  describe("#tokenizeUrl", () => {
+    it("should strip the leading www from a url", () => {
+      item = instance.tokenizeUrl(item, { field: "url", dest: "url_toks" });
+      assert.deepEqual(
+        [
+          "wonder",
+          "example",
+          "com",
+          "dir1",
+          "dir2a",
+          "dir2b",
+          "dir3",
+          "4",
+          "key1",
+          "key2",
+          "val2",
+          "key3",
+          "amp",
+          "3",
+          "4",
+        ],
+        item.url_toks
+      );
+    });
+    it("should tokenize the not strip the leading non-wwww token from a url", () => {
+      item = instance.tokenizeUrl(item, { field: "url2", dest: "url_toks" });
+      assert.deepEqual(
+        [
+          "wonder",
+          "example",
+          "com",
+          "dir1",
+          "dir2a",
+          "dir2b",
+          "dir3",
+          "4",
+          "key1",
+          "key2",
+          "val2",
+          "key3",
+          "amp",
+          "3",
+          "4",
+        ],
+        item.url_toks
+      );
+    });
+    it("should error for a missing url", () => {
+      item = instance.tokenizeUrl(item, { field: "missing", dest: "url_toks" });
+      assert.equal(item, null);
+    });
+  });
+
+  describe("#getUrlDomain", () => {
+    it("should get only the hostname skipping the www", () => {
+      item = instance.getUrlDomain(item, { field: "url", dest: "url_domain" });
+      assert.isTrue("url_domain" in item);
+      assert.deepEqual("wonder.example.com", item.url_domain);
+    });
+    it("should get only the hostname", () => {
+      item = instance.getUrlDomain(item, { field: "url2", dest: "url_domain" });
+      assert.isTrue("url_domain" in item);
+      assert.deepEqual("wonder.example.com", item.url_domain);
+    });
+    it("should get the hostname and 2 levels of directories", () => {
+      item = instance.getUrlDomain(item, {
+        field: "url",
+        path_length: 2,
+        dest: "url_plus_2",
+      });
+      assert.isTrue("url_plus_2" in item);
+      assert.deepEqual("wonder.example.com/dir1/dir2a-dir2b", item.url_plus_2);
+    });
+    it("should error for a missing url", () => {
+      item = instance.getUrlDomain(item, {
+        field: "missing",
+        dest: "url_domain",
+      });
+      assert.equal(item, null);
+    });
+  });
+
+  describe("#tokenizeField", () => {
+    it("should tokenize the field", () => {
+      item = instance.tokenizeField(item, { field: "text", dest: "toks" });
+      assert.isTrue("toks" in item);
+      assert.deepEqual(["this", "is", "a", "sentence"], item.toks);
+    });
+    it("should error for a missing field", () => {
+      item = instance.tokenizeField(item, { field: "missing", dest: "toks" });
+      assert.equal(item, null);
+    });
+    it("should error for a broken config", () => {
+      item = instance.tokenizeField(item, {});
+      assert.equal(item, null);
+    });
+  });
+
+  describe("#_typeOf", () => {
+    it("should know this is a map", () => {
+      assert.equal(instance._typeOf({}), "map");
+    });
+    it("should know this is an array", () => {
+      assert.equal(instance._typeOf([]), "array");
+    });
+    it("should know this is a string", () => {
+      assert.equal(instance._typeOf("blah"), "string");
+    });
+    it("should know this is a boolean", () => {
+      assert.equal(instance._typeOf(true), "boolean");
+    });
+
+    it("should know this is a null", () => {
+      assert.equal(instance._typeOf(null), "null");
+    });
+  });
+
+  describe("#_lookupScalar", () => {
+    it("should return the constant", () => {
+      assert.equal(instance._lookupScalar({}, 1, 0), 1);
+    });
+    it("should return the default", () => {
+      assert.equal(instance._lookupScalar({}, "blah", 42), 42);
+    });
+    it("should return the field's value", () => {
+      assert.equal(instance._lookupScalar({ blah: 11 }, "blah", 42), 11);
+    });
+  });
+
+  describe("#copyValue", () => {
+    it("should copy values", () => {
+      item = instance.copyValue(item, { src: "one", dest: "again" });
+      assert.isTrue("again" in item);
+      assert.equal(item.again, 1);
+      item.one = 100;
+      assert.equal(item.one, 100);
+      assert.equal(item.again, 1);
+    });
+    it("should handle maps corrects", () => {
+      item = instance.copyValue(item, { src: "map", dest: "again" });
+      assert.deepEqual(item.again, { a: 1, b: 2, c: 3 });
+      item.map.c = 100;
+      assert.deepEqual(item.again, { a: 1, b: 2, c: 3 });
+      item.map = 342;
+      assert.deepEqual(item.again, { a: 1, b: 2, c: 3 });
+    });
+    it("should error for a missing field", () => {
+      item = instance.copyValue(item, { src: "missing", dest: "toks" });
+      assert.equal(item, null);
+    });
+  });
+
+  describe("#keepTopK", () => {
+    it("should keep the 2 smallest", () => {
+      item = instance.keepTopK(item, { field: "map", k: 2, descending: false });
+      assert.equal(Object.keys(item.map).length, 2);
+      assert.isTrue("a" in item.map);
+      assert.equal(item.map.a, 1);
+      assert.isTrue("b" in item.map);
+      assert.equal(item.map.b, 2);
+      assert.isTrue(!("c" in item.map));
+    });
+    it("should keep the 2 largest", () => {
+      item = instance.keepTopK(item, { field: "map", k: 2, descending: true });
+      assert.equal(Object.keys(item.map).length, 2);
+      assert.isTrue(!("a" in item.map));
+      assert.isTrue("b" in item.map);
+      assert.equal(item.map.b, 2);
+      assert.isTrue("c" in item.map);
+      assert.equal(item.map.c, 3);
+    });
+    it("should still keep the 2 largest", () => {
+      item = instance.keepTopK(item, { field: "map", k: 2 });
+      assert.equal(Object.keys(item.map).length, 2);
+      assert.isTrue(!("a" in item.map));
+      assert.isTrue("b" in item.map);
+      assert.equal(item.map.b, 2);
+      assert.isTrue("c" in item.map);
+      assert.equal(item.map.c, 3);
+    });
+    it("should promote up nested fields", () => {
+      item = instance.keepTopK(item, { field: "tags", k: 2 });
+      assert.equal(Object.keys(item.tags).length, 2);
+      assert.deepEqual(item.tags, { bb: 5, bc: 6 });
+    });
+    it("should error for a missing field", () => {
+      item = instance.keepTopK(item, { field: "missing", k: 3 });
+      assert.equal(item, null);
+    });
+  });
+
+  describe("#scalarMultiply", () => {
+    it("should use constants", () => {
+      item = instance.scalarMultiply(item, { field: "map", k: 2 });
+      assert.equal(item.map.a, 2);
+      assert.equal(item.map.b, 4);
+      assert.equal(item.map.c, 6);
+    });
+    it("should use fields", () => {
+      item = instance.scalarMultiply(item, { field: "map", k: "three" });
+      assert.equal(item.map.a, 3);
+      assert.equal(item.map.b, 6);
+      assert.equal(item.map.c, 9);
+    });
+    it("should use default", () => {
+      item = instance.scalarMultiply(item, {
+        field: "map",
+        k: "missing",
+        dfault: 4,
+      });
+      assert.equal(item.map.a, 4);
+      assert.equal(item.map.b, 8);
+      assert.equal(item.map.c, 12);
+    });
+    it("should error for a missing field", () => {
+      item = instance.scalarMultiply(item, { field: "missing", k: 3 });
+      assert.equal(item, null);
+    });
+    it("should multiply numbers", () => {
+      item = instance.scalarMultiply(item, { field: "lhs", k: 2 });
+      assert.equal(item.lhs, 4);
+    });
+    it("should multiply arrays", () => {
+      item = instance.scalarMultiply(item, { field: "arr1", k: 2 });
+      assert.deepEqual(item.arr1, [4, 6, 8]);
+    });
+    it("should should error on strings", () => {
+      item = instance.scalarMultiply(item, { field: "foo", k: 2 });
+      assert.equal(item, null);
+    });
+  });
+
+  describe("#elementwiseMultiply", () => {
+    it("should handle maps", () => {
+      item = instance.elementwiseMultiply(item, {
+        left: "tags",
+        right: "map2",
+      });
+      assert.deepEqual(item.tags, {
+        a: { aa: 0, ab: 0, ac: 0 },
+        b: { ba: 8, bb: 10, bc: 12 },
+      });
+    });
+    it("should handle arrays of same length", () => {
+      item = instance.elementwiseMultiply(item, {
+        left: "arr1",
+        right: "arr2",
+      });
+      assert.deepEqual(item.arr1, [6, 12, 20]);
+    });
+    it("should error for arrays of different lengths", () => {
+      item = instance.elementwiseMultiply(item, {
+        left: "arr1",
+        right: "long",
+      });
+      assert.equal(item, null);
+    });
+    it("should error for a missing left", () => {
+      item = instance.elementwiseMultiply(item, {
+        left: "missing",
+        right: "arr2",
+      });
+      assert.equal(item, null);
+    });
+    it("should error for a missing right", () => {
+      item = instance.elementwiseMultiply(item, {
+        left: "arr1",
+        right: "missing",
+      });
+      assert.equal(item, null);
+    });
+    it("should handle numbers", () => {
+      item = instance.elementwiseMultiply(item, {
+        left: "three",
+        right: "two",
+      });
+      assert.equal(item.three, 6);
+    });
+    it("should error for mismatched types", () => {
+      item = instance.elementwiseMultiply(item, { left: "arr1", right: "two" });
+      assert.equal(item, null);
+    });
+    it("should error for strings", () => {
+      item = instance.elementwiseMultiply(item, { left: "foo", right: "bar" });
+      assert.equal(item, null);
+    });
+  });
+
+  describe("#vectorMultiply", () => {
+    it("should calculate dot products from maps", () => {
+      item = instance.vectorMultiply(item, {
+        left: "map",
+        right: "map2",
+        dest: "dot",
+      });
+      assert.equal(item.dot, 13);
+    });
+    it("should calculate dot products from arrays", () => {
+      item = instance.vectorMultiply(item, {
+        left: "arr1",
+        right: "arr2",
+        dest: "dot",
+      });
+      assert.equal(item.dot, 38);
+    });
+    it("should error for arrays of different lengths", () => {
+      item = instance.vectorMultiply(item, { left: "arr1", right: "long" });
+      assert.equal(item, null);
+    });
+    it("should error for a missing left", () => {
+      item = instance.vectorMultiply(item, { left: "missing", right: "arr2" });
+      assert.equal(item, null);
+    });
+    it("should error for a missing right", () => {
+      item = instance.vectorMultiply(item, { left: "arr1", right: "missing" });
+      assert.equal(item, null);
+    });
+    it("should error for mismatched types", () => {
+      item = instance.vectorMultiply(item, { left: "arr1", right: "two" });
+      assert.equal(item, null);
+    });
+    it("should error for strings", () => {
+      item = instance.vectorMultiply(item, { left: "foo", right: "bar" });
+      assert.equal(item, null);
+    });
+  });
+
+  describe("#scalarAdd", () => {
+    it("should error for a missing field", () => {
+      item = instance.scalarAdd(item, { field: "missing", k: 10 });
+      assert.equal(item, null);
+    });
+    it("should error for strings", () => {
+      item = instance.scalarAdd(item, { field: "foo", k: 10 });
+      assert.equal(item, null);
+    });
+    it("should work for numbers", () => {
+      item = instance.scalarAdd(item, { field: "one", k: 10 });
+      assert.equal(item.one, 11);
+    });
+    it("should add a constant to every cell on a map", () => {
+      item = instance.scalarAdd(item, { field: "map", k: 10 });
+      assert.deepEqual(item.map, { a: 11, b: 12, c: 13 });
+    });
+    it("should add a value from a field to every cell on a map", () => {
+      item = instance.scalarAdd(item, { field: "map", k: "qux" });
+      assert.deepEqual(item.map, { a: 43, b: 44, c: 45 });
+    });
+    it("should add a constant to every cell on an array", () => {
+      item = instance.scalarAdd(item, { field: "arr1", k: 10 });
+      assert.deepEqual(item.arr1, [12, 13, 14]);
+    });
+  });
+
+  describe("#vectorAdd", () => {
+    it("should calculate add vectors from maps", () => {
+      item = instance.vectorAdd(item, { left: "map", right: "map2" });
+      assert.equal(Object.keys(item.map).length, 4);
+      assert.isTrue("a" in item.map);
+      assert.equal(item.map.a, 1);
+      assert.isTrue("b" in item.map);
+      assert.equal(item.map.b, 4);
+      assert.isTrue("c" in item.map);
+      assert.equal(item.map.c, 6);
+      assert.isTrue("d" in item.map);
+      assert.equal(item.map.d, 4);
+    });
+    it("should work for missing left", () => {
+      item = instance.vectorAdd(item, { left: "missing", right: "arr2" });
+      assert.deepEqual(item.missing, [3, 4, 5]);
+    });
+    it("should error for missing right", () => {
+      item = instance.vectorAdd(item, { left: "arr2", right: "missing" });
+      assert.equal(item, null);
+    });
+    it("should error error for strings", () => {
+      item = instance.vectorAdd(item, { left: "foo", right: "bar" });
+      assert.equal(item, null);
+    });
+    it("should error for different types", () => {
+      item = instance.vectorAdd(item, { left: "arr2", right: "map" });
+      assert.equal(item, null);
+    });
+    it("should calculate add vectors from arrays", () => {
+      item = instance.vectorAdd(item, { left: "arr1", right: "arr2" });
+      assert.deepEqual(item.arr1, [5, 7, 9]);
+    });
+    it("should abort on different sized arrays", () => {
+      item = instance.vectorAdd(item, { left: "arr1", right: "long" });
+      assert.equal(item, null);
+    });
+    it("should calculate add vectors from arrays", () => {
+      item = instance.vectorAdd(item, { left: "arr1", right: "arr2" });
+      assert.deepEqual(item.arr1, [5, 7, 9]);
+    });
+  });
+
+  describe("#makeBoolean", () => {
+    it("should error for missing field", () => {
+      item = instance.makeBoolean(item, { field: "missing", threshold: 2 });
+      assert.equal(item, null);
+    });
+    it("should 0/1 a map", () => {
+      item = instance.makeBoolean(item, { field: "map", threshold: 2 });
+      assert.deepEqual(item.map, { a: 0, b: 0, c: 1 });
+    });
+    it("should a map of all 1s", () => {
+      item = instance.makeBoolean(item, { field: "map" });
+      assert.deepEqual(item.map, { a: 1, b: 1, c: 1 });
+    });
+    it("should -1/1 a map", () => {
+      item = instance.makeBoolean(item, {
+        field: "map",
+        threshold: 2,
+        keep_negative: true,
+      });
+      assert.deepEqual(item.map, { a: -1, b: -1, c: 1 });
+    });
+    it("should work an array", () => {
+      item = instance.makeBoolean(item, { field: "arr1", threshold: 3 });
+      assert.deepEqual(item.arr1, [0, 0, 1]);
+    });
+    it("should -1/1 an array", () => {
+      item = instance.makeBoolean(item, {
+        field: "arr1",
+        threshold: 3,
+        keep_negative: true,
+      });
+      assert.deepEqual(item.arr1, [-1, -1, 1]);
+    });
+    it("should 1 a high number", () => {
+      item = instance.makeBoolean(item, { field: "qux", threshold: 3 });
+      assert.equal(item.qux, 1);
+    });
+    it("should 0 a low number", () => {
+      item = instance.makeBoolean(item, { field: "qux", threshold: 70 });
+      assert.equal(item.qux, 0);
+    });
+    it("should -1 a low number", () => {
+      item = instance.makeBoolean(item, {
+        field: "qux",
+        threshold: 83,
+        keep_negative: true,
+      });
+      assert.equal(item.qux, -1);
+    });
+    it("should fail a string", () => {
+      item = instance.makeBoolean(item, { field: "foo", threshold: 3 });
+      assert.equal(item, null);
+    });
+  });
+
+  describe("#allowFields", () => {
+    it("should filter the keys out of a map", () => {
+      item = instance.allowFields(item, {
+        fields: ["foo", "missing", "bar"],
+      });
+      assert.deepEqual(item, { foo: "FOO", bar: "BAR" });
+    });
+  });
+
+  describe("#filterByValue", () => {
+    it("should fail on missing field", () => {
+      item = instance.filterByValue(item, { field: "missing", threshold: 2 });
+      assert.equal(item, null);
+    });
+    it("should filter the keys out of a map", () => {
+      item = instance.filterByValue(item, { field: "map", threshold: 2 });
+      assert.deepEqual(item.map, { c: 3 });
+    });
+  });
+
+  describe("#l2Normalize", () => {
+    it("should fail on missing field", () => {
+      item = instance.l2Normalize(item, { field: "missing" });
+      assert.equal(item, null);
+    });
+    it("should L2 normalize an array", () => {
+      item = instance.l2Normalize(item, { field: "arr1" });
+      assert.deepEqual(
+        item.arr1,
+        [0.3713906763541037, 0.5570860145311556, 0.7427813527082074]
+      );
+    });
+    it("should L2 normalize a map", () => {
+      item = instance.l2Normalize(item, { field: "map" });
+      assert.deepEqual(item.map, {
+        a: 0.2672612419124244,
+        b: 0.5345224838248488,
+        c: 0.8017837257372732,
+      });
+    });
+    it("should fail a string", () => {
+      item = instance.l2Normalize(item, { field: "foo" });
+      assert.equal(item, null);
+    });
+    it("should not bomb on a zero vector", () => {
+      item = instance.l2Normalize(item, { field: "zero" });
+      assert.deepEqual(item.zero, { a: 0, b: 0 });
+      item = instance.l2Normalize(item, { field: "zaro" });
+      assert.deepEqual(item.zaro, [0, 0]);
+    });
+  });
+
+  describe("#probNormalize", () => {
+    it("should fail on missing field", () => {
+      item = instance.probNormalize(item, { field: "missing" });
+      assert.equal(item, null);
+    });
+    it("should normalize an array to sum to 1", () => {
+      item = instance.probNormalize(item, { field: "arr1" });
+      assert.deepEqual(
+        item.arr1,
+        [0.2222222222222222, 0.3333333333333333, 0.4444444444444444]
+      );
+    });
+    it("should normalize a map to sum to 1", () => {
+      item = instance.probNormalize(item, { field: "map" });
+      assert.equal(Object.keys(item.map).length, 3);
+      assert.isTrue("a" in item.map);
+      assert.isTrue(Math.abs(item.map.a - 0.16667) <= EPSILON);
+      assert.isTrue("b" in item.map);
+      assert.isTrue(Math.abs(item.map.b - 0.33333) <= EPSILON);
+      assert.isTrue("c" in item.map);
+      assert.isTrue(Math.abs(item.map.c - 0.5) <= EPSILON);
+    });
+    it("should fail a string", () => {
+      item = instance.probNormalize(item, { field: "foo" });
+      assert.equal(item, null);
+    });
+    it("should not bomb on a zero vector", () => {
+      item = instance.probNormalize(item, { field: "zero" });
+      assert.deepEqual(item.zero, { a: 0, b: 0 });
+      item = instance.probNormalize(item, { field: "zaro" });
+      assert.deepEqual(item.zaro, [0, 0]);
+    });
+  });
+
+  describe("#scalarMultiplyTag", () => {
+    it("should fail on missing field", () => {
+      item = instance.scalarMultiplyTag(item, { field: "missing", k: 3 });
+      assert.equal(item, null);
+    });
+    it("should scalar multiply a nested map", () => {
+      item = instance.scalarMultiplyTag(item, {
+        field: "tags",
+        k: 3,
+        log_scale: false,
+      });
+      assert.isTrue(Math.abs(item.tags.a.aa - 0.3) <= EPSILON);
+      assert.isTrue(Math.abs(item.tags.a.ab - 0.6) <= EPSILON);
+      assert.isTrue(Math.abs(item.tags.a.ac - 0.9) <= EPSILON);
+      assert.isTrue(Math.abs(item.tags.b.ba - 12) <= EPSILON);
+      assert.isTrue(Math.abs(item.tags.b.bb - 15) <= EPSILON);
+      assert.isTrue(Math.abs(item.tags.b.bc - 18) <= EPSILON);
+    });
+    it("should scalar multiply a nested map with logrithms", () => {
+      item = instance.scalarMultiplyTag(item, {
+        field: "tags",
+        k: 3,
+        log_scale: true,
+      });
+      assert.isTrue(
+        Math.abs(item.tags.a.aa - Math.log(0.1 + 0.000001) * 3) <= EPSILON
+      );
+      assert.isTrue(
+        Math.abs(item.tags.a.ab - Math.log(0.2 + 0.000001) * 3) <= EPSILON
+      );
+      assert.isTrue(
+        Math.abs(item.tags.a.ac - Math.log(0.3 + 0.000001) * 3) <= EPSILON
+      );
+      assert.isTrue(
+        Math.abs(item.tags.b.ba - Math.log(4.0 + 0.000001) * 3) <= EPSILON
+      );
+      assert.isTrue(
+        Math.abs(item.tags.b.bb - Math.log(5.0 + 0.000001) * 3) <= EPSILON
+      );
+      assert.isTrue(
+        Math.abs(item.tags.b.bc - Math.log(6.0 + 0.000001) * 3) <= EPSILON
+      );
+    });
+    it("should fail a string", () => {
+      item = instance.scalarMultiplyTag(item, { field: "foo", k: 3 });
+      assert.equal(item, null);
+    });
+  });
+
+  describe("#setDefault", () => {
+    it("should store a missing value", () => {
+      item = instance.setDefault(item, { field: "missing", value: 1111 });
+      assert.equal(item.missing, 1111);
+    });
+    it("should not overwrite an existing value", () => {
+      item = instance.setDefault(item, { field: "lhs", value: 1111 });
+      assert.equal(item.lhs, 2);
+    });
+    it("should store a complex value", () => {
+      item = instance.setDefault(item, { field: "missing", value: { a: 1 } });
+      assert.deepEqual(item.missing, { a: 1 });
+    });
+  });
+
+  describe("#lookupValue", () => {
+    it("should promote a value", () => {
+      item = instance.lookupValue(item, {
+        haystack: "map",
+        needle: "c",
+        dest: "ccc",
+      });
+      assert.equal(item.ccc, 3);
+    });
+    it("should handle a missing haystack", () => {
+      item = instance.lookupValue(item, {
+        haystack: "missing",
+        needle: "c",
+        dest: "ccc",
+      });
+      assert.isTrue(!("ccc" in item));
+    });
+    it("should handle a missing needle", () => {
+      item = instance.lookupValue(item, {
+        haystack: "map",
+        needle: "missing",
+        dest: "ccc",
+      });
+      assert.isTrue(!("ccc" in item));
+    });
+  });
+
+  describe("#copyToMap", () => {
+    it("should copy a value to a map", () => {
+      item = instance.copyToMap(item, {
+        src: "qux",
+        dest_map: "map",
+        dest_key: "zzz",
+      });
+      assert.isTrue("zzz" in item.map);
+      assert.equal(item.map.zzz, item.qux);
+    });
+    it("should create a new map to hold the key", () => {
+      item = instance.copyToMap(item, {
+        src: "qux",
+        dest_map: "missing",
+        dest_key: "zzz",
+      });
+      assert.equal(Object.keys(item.missing).length, 1);
+      assert.equal(item.missing.zzz, item.qux);
+    });
+    it("should not create an empty map if the src is missing", () => {
+      item = instance.copyToMap(item, {
+        src: "missing",
+        dest_map: "no_map",
+        dest_key: "zzz",
+      });
+      assert.isTrue(!("no_map" in item));
+    });
+  });
+
+  describe("#applySoftmaxTags", () => {
+    it("should error on missing field", () => {
+      item = instance.applySoftmaxTags(item, { field: "missing" });
+      assert.equal(item, null);
+    });
+    it("should error on nonmaps", () => {
+      item = instance.applySoftmaxTags(item, { field: "arr1" });
+      assert.equal(item, null);
+    });
+    it("should error on unnested maps", () => {
+      item = instance.applySoftmaxTags(item, { field: "map" });
+      assert.equal(item, null);
+    });
+    it("should error on wrong nested maps", () => {
+      item = instance.applySoftmaxTags(item, { field: "bogus" });
+      assert.equal(item, null);
+    });
+    it("should apply softmax across the subtags", () => {
+      item = instance.applySoftmaxTags(item, { field: "tags" });
+      assert.isTrue("a" in item.tags);
+      assert.isTrue("aa" in item.tags.a);
+      assert.isTrue("ab" in item.tags.a);
+      assert.isTrue("ac" in item.tags.a);
+      assert.isTrue(Math.abs(item.tags.a.aa - 0.30061) <= EPSILON);
+      assert.isTrue(Math.abs(item.tags.a.ab - 0.33222) <= EPSILON);
+      assert.isTrue(Math.abs(item.tags.a.ac - 0.36717) <= EPSILON);
+
+      assert.isTrue("b" in item.tags);
+      assert.isTrue("ba" in item.tags.b);
+      assert.isTrue("bb" in item.tags.b);
+      assert.isTrue("bc" in item.tags.b);
+      assert.isTrue(Math.abs(item.tags.b.ba - 0.09003) <= EPSILON);
+      assert.isTrue(Math.abs(item.tags.b.bb - 0.24473) <= EPSILON);
+      assert.isTrue(Math.abs(item.tags.b.bc - 0.66524) <= EPSILON);
+    });
+  });
+
+  describe("#combinerAdd", () => {
+    it("should do nothing when right field is missing", () => {
+      let right = makeItem();
+      let combined = instance.combinerAdd(item, right, { field: "missing" });
+      assert.deepEqual(combined, item);
+    });
+    it("should handle missing left maps", () => {
+      let right = makeItem();
+      right.missingmap = { a: 5, b: -1, c: 3 };
+      let combined = instance.combinerAdd(item, right, { field: "missingmap" });
+      assert.deepEqual(combined.missingmap, { a: 5, b: -1, c: 3 });
+    });
+    it("should add equal sized maps", () => {
+      let right = makeItem();
+      let combined = instance.combinerAdd(item, right, { field: "map" });
+      assert.deepEqual(combined.map, { a: 2, b: 4, c: 6 });
+    });
+    it("should add long map to short map", () => {
+      let right = makeItem();
+      right.map.d = 999;
+      let combined = instance.combinerAdd(item, right, { field: "map" });
+      assert.deepEqual(combined.map, { a: 2, b: 4, c: 6, d: 999 });
+    });
+    it("should add short map to long map", () => {
+      let right = makeItem();
+      item.map.d = 999;
+      let combined = instance.combinerAdd(item, right, { field: "map" });
+      assert.deepEqual(combined.map, { a: 2, b: 4, c: 6, d: 999 });
+    });
+    it("should add equal sized arrays", () => {
+      let right = makeItem();
+      let combined = instance.combinerAdd(item, right, { field: "arr1" });
+      assert.deepEqual(combined.arr1, [4, 6, 8]);
+    });
+    it("should handle missing left arrays", () => {
+      let right = makeItem();
+      right.missingarray = [5, 1, 4];
+      let combined = instance.combinerAdd(item, right, {
+        field: "missingarray",
+      });
+      assert.deepEqual(combined.missingarray, [5, 1, 4]);
+    });
+    it("should add long array to short array", () => {
+      let right = makeItem();
+      right.arr1 = [2, 3, 4, 12];
+      let combined = instance.combinerAdd(item, right, { field: "arr1" });
+      assert.deepEqual(combined.arr1, [4, 6, 8, 12]);
+    });
+    it("should add short array to long array", () => {
+      let right = makeItem();
+      item.arr1 = [2, 3, 4, 12];
+      let combined = instance.combinerAdd(item, right, { field: "arr1" });
+      assert.deepEqual(combined.arr1, [4, 6, 8, 12]);
+    });
+    it("should handle missing left number", () => {
+      let right = makeItem();
+      right.missingnumber = 999;
+      let combined = instance.combinerAdd(item, right, {
+        field: "missingnumber",
+      });
+      assert.deepEqual(combined.missingnumber, 999);
+    });
+    it("should add numbers", () => {
+      let right = makeItem();
+      let combined = instance.combinerAdd(item, right, { field: "lhs" });
+      assert.equal(combined.lhs, 4);
+    });
+    it("should error on missing left, and right is a string", () => {
+      let right = makeItem();
+      right.error = "error";
+      let combined = instance.combinerAdd(item, right, { field: "error" });
+      assert.equal(combined, null);
+    });
+    it("should error on left string", () => {
+      let right = makeItem();
+      let combined = instance.combinerAdd(item, right, { field: "foo" });
+      assert.equal(combined, null);
+    });
+    it("should error on mismatch types", () => {
+      let right = makeItem();
+      right.lhs = [1, 2, 3];
+      let combined = instance.combinerAdd(item, right, { field: "lhs" });
+      assert.equal(combined, null);
+    });
+  });
+
+  describe("#combinerMax", () => {
+    it("should do nothing when right field is missing", () => {
+      let right = makeItem();
+      let combined = instance.combinerMax(item, right, { field: "missing" });
+      assert.deepEqual(combined, item);
+    });
+    it("should handle missing left maps", () => {
+      let right = makeItem();
+      right.missingmap = { a: 5, b: -1, c: 3 };
+      let combined = instance.combinerMax(item, right, { field: "missingmap" });
+      assert.deepEqual(combined.missingmap, { a: 5, b: -1, c: 3 });
+    });
+    it("should handle equal sized maps", () => {
+      let right = makeItem();
+      right.map = { a: 5, b: -1, c: 3 };
+      let combined = instance.combinerMax(item, right, { field: "map" });
+      assert.deepEqual(combined.map, { a: 5, b: 2, c: 3 });
+    });
+    it("should handle short map to long map", () => {
+      let right = makeItem();
+      right.map = { a: 5, b: -1, c: 3, d: 999 };
+      let combined = instance.combinerMax(item, right, { field: "map" });
+      assert.deepEqual(combined.map, { a: 5, b: 2, c: 3, d: 999 });
+    });
+    it("should handle long map to short map", () => {
+      let right = makeItem();
+      right.map = { a: 5, b: -1, c: 3 };
+      item.map.d = 999;
+      let combined = instance.combinerMax(item, right, { field: "map" });
+      assert.deepEqual(combined.map, { a: 5, b: 2, c: 3, d: 999 });
+    });
+    it("should handle equal sized arrays", () => {
+      let right = makeItem();
+      right.arr1 = [5, 1, 4];
+      let combined = instance.combinerMax(item, right, { field: "arr1" });
+      assert.deepEqual(combined.arr1, [5, 3, 4]);
+    });
+    it("should handle missing left arrays", () => {
+      let right = makeItem();
+      right.missingarray = [5, 1, 4];
+      let combined = instance.combinerMax(item, right, {
+        field: "missingarray",
+      });
+      assert.deepEqual(combined.missingarray, [5, 1, 4]);
+    });
+    it("should handle short array to long array", () => {
+      let right = makeItem();
+      right.arr1 = [5, 1, 4, 7];
+      let combined = instance.combinerMax(item, right, { field: "arr1" });
+      assert.deepEqual(combined.arr1, [5, 3, 4, 7]);
+    });
+    it("should handle long array to short array", () => {
+      let right = makeItem();
+      right.arr1 = [5, 1, 4];
+      item.arr1.push(7);
+      let combined = instance.combinerMax(item, right, { field: "arr1" });
+      assert.deepEqual(combined.arr1, [5, 3, 4, 7]);
+    });
+    it("should handle missing left number", () => {
+      let right = makeItem();
+      right.missingnumber = 999;
+      let combined = instance.combinerMax(item, right, {
+        field: "missingnumber",
+      });
+      assert.deepEqual(combined.missingnumber, 999);
+    });
+    it("should handle big number", () => {
+      let right = makeItem();
+      right.lhs = 99;
+      let combined = instance.combinerMax(item, right, { field: "lhs" });
+      assert.equal(combined.lhs, 99);
+    });
+    it("should handle small number", () => {
+      let right = makeItem();
+      item.lhs = 99;
+      let combined = instance.combinerMax(item, right, { field: "lhs" });
+      assert.equal(combined.lhs, 99);
+    });
+    it("should error on missing left, and right is a string", () => {
+      let right = makeItem();
+      right.error = "error";
+      let combined = instance.combinerMax(item, right, { field: "error" });
+      assert.equal(combined, null);
+    });
+    it("should error on left string", () => {
+      let right = makeItem();
+      let combined = instance.combinerMax(item, right, { field: "foo" });
+      assert.equal(combined, null);
+    });
+    it("should error on mismatch types", () => {
+      let right = makeItem();
+      right.lhs = [1, 2, 3];
+      let combined = instance.combinerMax(item, right, { field: "lhs" });
+      assert.equal(combined, null);
+    });
+  });
+
+  describe("#combinerCollectValues", () => {
+    it("should error on bogus operation", () => {
+      let right = makeItem();
+      right.url_domain = "maseratiusa.com/maserati";
+      right.time = 41;
+      let combined = instance.combinerCollectValues(item, right, {
+        left_field: "combined_map",
+        right_key_field: "url_domain",
+        right_value_field: "time",
+        operation: "missing",
+      });
+      assert.equal(combined, null);
+    });
+    it("should sum when missing left", () => {
+      let right = makeItem();
+      right.url_domain = "maseratiusa.com/maserati";
+      right.time = 41;
+      let combined = instance.combinerCollectValues(item, right, {
+        left_field: "combined_map",
+        right_key_field: "url_domain",
+        right_value_field: "time",
+        operation: "sum",
+      });
+      assert.deepEqual(combined.combined_map, {
+        "maseratiusa.com/maserati": 41,
+      });
+    });
+    it("should sum when missing right", () => {
+      let right = makeItem();
+      item.combined_map = { fake: 42 };
+      let combined = instance.combinerCollectValues(item, right, {
+        left_field: "combined_map",
+        right_key_field: "url_domain",
+        right_value_field: "time",
+        operation: "sum",
+      });
+      assert.deepEqual(combined.combined_map, { fake: 42 });
+    });
+    it("should sum when both", () => {
+      let right = makeItem();
+      right.url_domain = "maseratiusa.com/maserati";
+      right.time = 41;
+      item.combined_map = { fake: 42, "maseratiusa.com/maserati": 41 };
+      let combined = instance.combinerCollectValues(item, right, {
+        left_field: "combined_map",
+        right_key_field: "url_domain",
+        right_value_field: "time",
+        operation: "sum",
+      });
+      assert.deepEqual(combined.combined_map, {
+        fake: 42,
+        "maseratiusa.com/maserati": 82,
+      });
+    });
+
+    it("should max when missing left", () => {
+      let right = makeItem();
+      right.url_domain = "maseratiusa.com/maserati";
+      right.time = 41;
+      let combined = instance.combinerCollectValues(item, right, {
+        left_field: "combined_map",
+        right_key_field: "url_domain",
+        right_value_field: "time",
+        operation: "max",
+      });
+      assert.deepEqual(combined.combined_map, {
+        "maseratiusa.com/maserati": 41,
+      });
+    });
+    it("should max when missing right", () => {
+      let right = makeItem();
+      item.combined_map = { fake: 42 };
+      let combined = instance.combinerCollectValues(item, right, {
+        left_field: "combined_map",
+        right_key_field: "url_domain",
+        right_value_field: "time",
+        operation: "max",
+      });
+      assert.deepEqual(combined.combined_map, { fake: 42 });
+    });
+    it("should max when both (right)", () => {
+      let right = makeItem();
+      right.url_domain = "maseratiusa.com/maserati";
+      right.time = 99;
+      item.combined_map = { fake: 42, "maseratiusa.com/maserati": 41 };
+      let combined = instance.combinerCollectValues(item, right, {
+        left_field: "combined_map",
+        right_key_field: "url_domain",
+        right_value_field: "time",
+        operation: "max",
+      });
+      assert.deepEqual(combined.combined_map, {
+        fake: 42,
+        "maseratiusa.com/maserati": 99,
+      });
+    });
+    it("should max when both (left)", () => {
+      let right = makeItem();
+      right.url_domain = "maseratiusa.com/maserati";
+      right.time = -99;
+      item.combined_map = { fake: 42, "maseratiusa.com/maserati": 41 };
+      let combined = instance.combinerCollectValues(item, right, {
+        left_field: "combined_map",
+        right_key_field: "url_domain",
+        right_value_field: "time",
+        operation: "max",
+      });
+      assert.deepEqual(combined.combined_map, {
+        fake: 42,
+        "maseratiusa.com/maserati": 41,
+      });
+    });
+
+    it("should overwrite when missing left", () => {
+      let right = makeItem();
+      right.url_domain = "maseratiusa.com/maserati";
+      right.time = 41;
+      let combined = instance.combinerCollectValues(item, right, {
+        left_field: "combined_map",
+        right_key_field: "url_domain",
+        right_value_field: "time",
+        operation: "overwrite",
+      });
+      assert.deepEqual(combined.combined_map, {
+        "maseratiusa.com/maserati": 41,
+      });
+    });
+    it("should overwrite when missing right", () => {
+      let right = makeItem();
+      item.combined_map = { fake: 42 };
+      let combined = instance.combinerCollectValues(item, right, {
+        left_field: "combined_map",
+        right_key_field: "url_domain",
+        right_value_field: "time",
+        operation: "overwrite",
+      });
+      assert.deepEqual(combined.combined_map, { fake: 42 });
+    });
+    it("should overwrite when both", () => {
+      let right = makeItem();
+      right.url_domain = "maseratiusa.com/maserati";
+      right.time = 41;
+      item.combined_map = { fake: 42, "maseratiusa.com/maserati": 77 };
+      let combined = instance.combinerCollectValues(item, right, {
+        left_field: "combined_map",
+        right_key_field: "url_domain",
+        right_value_field: "time",
+        operation: "overwrite",
+      });
+      assert.deepEqual(combined.combined_map, {
+        fake: 42,
+        "maseratiusa.com/maserati": 41,
+      });
+    });
+
+    it("should count when missing left", () => {
+      let right = makeItem();
+      right.url_domain = "maseratiusa.com/maserati";
+      right.time = 41;
+      let combined = instance.combinerCollectValues(item, right, {
+        left_field: "combined_map",
+        right_key_field: "url_domain",
+        right_value_field: "time",
+        operation: "count",
+      });
+      assert.deepEqual(combined.combined_map, {
+        "maseratiusa.com/maserati": 1,
+      });
+    });
+    it("should count when missing right", () => {
+      let right = makeItem();
+      item.combined_map = { fake: 42 };
+      let combined = instance.combinerCollectValues(item, right, {
+        left_field: "combined_map",
+        right_key_field: "url_domain",
+        right_value_field: "time",
+        operation: "count",
+      });
+      assert.deepEqual(combined.combined_map, { fake: 42 });
+    });
+    it("should count when both", () => {
+      let right = makeItem();
+      right.url_domain = "maseratiusa.com/maserati";
+      right.time = 41;
+      item.combined_map = { fake: 42, "maseratiusa.com/maserati": 1 };
+      let combined = instance.combinerCollectValues(item, right, {
+        left_field: "combined_map",
+        right_key_field: "url_domain",
+        right_value_field: "time",
+        operation: "count",
+      });
+      assert.deepEqual(combined.combined_map, {
+        fake: 42,
+        "maseratiusa.com/maserati": 2,
+      });
+    });
+  });
+
+  describe("#executeRecipe", () => {
+    it("should handle working steps", () => {
+      let final = instance.executeRecipe({}, [
+        { function: "set_default", field: "foo", value: 1 },
+        { function: "set_default", field: "bar", value: 10 },
+      ]);
+      assert.equal(final.foo, 1);
+      assert.equal(final.bar, 10);
+    });
+    it("should handle unknown steps", () => {
+      let final = instance.executeRecipe({}, [
+        { function: "set_default", field: "foo", value: 1 },
+        { function: "missing" },
+        { function: "set_default", field: "bar", value: 10 },
+      ]);
+      assert.equal(final, null);
+    });
+    it("should handle erroring steps", () => {
+      let final = instance.executeRecipe({}, [
+        { function: "set_default", field: "foo", value: 1 },
+        {
+          function: "accept_item_by_field_value",
+          field: "missing",
+          op: "invalid",
+          rhsField: "moot",
+          rhsValue: "m00t",
+        },
+        { function: "set_default", field: "bar", value: 10 },
+      ]);
+      assert.equal(final, null);
+    });
+  });
+
+  describe("#executeCombinerRecipe", () => {
+    it("should handle working steps", () => {
+      let final = instance.executeCombinerRecipe(
+        { foo: 1, bar: 10 },
+        { foo: 1, bar: 10 },
+        [
+          { function: "combiner_add", field: "foo" },
+          { function: "combiner_add", field: "bar" },
+        ]
+      );
+      assert.equal(final.foo, 2);
+      assert.equal(final.bar, 20);
+    });
+    it("should handle unknown steps", () => {
+      let final = instance.executeCombinerRecipe(
+        { foo: 1, bar: 10 },
+        { foo: 1, bar: 10 },
+        [
+          { function: "combiner_add", field: "foo" },
+          { function: "missing" },
+          { function: "combiner_add", field: "bar" },
+        ]
+      );
+      assert.equal(final, null);
+    });
+    it("should handle erroring steps", () => {
+      let final = instance.executeCombinerRecipe(
+        { foo: 1, bar: 10, baz: 0 },
+        { foo: 1, bar: 10, baz: "hundred" },
+        [
+          { function: "combiner_add", field: "foo" },
+          { function: "combiner_add", field: "baz" },
+          { function: "combiner_add", field: "bar" },
+        ]
+      );
+      assert.equal(final, null);
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/PersonalityProvider/Tokenize.test.js b/browser/components/newtab/test/unit/lib/PersonalityProvider/Tokenize.test.js
new file mode 100644
index 0000000000..19e738d451
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/PersonalityProvider/Tokenize.test.js
@@ -0,0 +1,134 @@
+import {
+  tokenize,
+  toksToTfIdfVector,
+} from "lib/PersonalityProvider/Tokenize.mjs";
+
+const EPSILON = 0.00001;
+
+describe("TF-IDF Term Vectorizer", () => {
+  describe("#tokenize", () => {
+    let testCases = [
+      { input: "HELLO there", expected: ["hello", "there"] },
+      { input: "blah,,,blah,blah", expected: ["blah", "blah", "blah"] },
+      {
+        input: "Call Jenny: 967-5309",
+        expected: ["call", "jenny", "967", "5309"],
+      },
+      {
+        input: "Yo(what)[[hello]]{{jim}}}bob{1:2:1+2=$3",
+        expected: [
+          "yo",
+          "what",
+          "hello",
+          "jim",
+          "bob",
+          "1",
+          "2",
+          "1",
+          "2",
+          "3",
+        ],
+      },
+      { input: "čÄfė 80's", expected: ["čäfė", "80", "s"] },
+      { input: "我知道很多东西。", expected: ["我知道很多东西"] },
+    ];
+    let checkTokenization = tc => {
+      it(`${tc.input} should tokenize to ${tc.expected}`, () => {
+        assert.deepEqual(tc.expected, tokenize(tc.input));
+      });
+    };
+
+    for (let i = 0; i < testCases.length; i++) {
+      checkTokenization(testCases[i]);
+    }
+  });
+
+  describe("#tfidf", () => {
+    let vocab_idfs = {
+      deal: [221, 5.5058519847862275],
+      easy: [269, 5.5058519847862275],
+      tanks: [867, 5.601162164590552],
+      sites: [792, 5.957837108529285],
+      care: [153, 5.957837108529285],
+      needs: [596, 5.824305715904762],
+      finally: [334, 5.706522680248379],
+    };
+    let testCases = [
+      {
+        input: "Finally! Easy care for your tanks!",
+        expected: {
+          finally: [334, 0.5009816295853761],
+          easy: [269, 0.48336453811728713],
+          care: [153, 0.5230447876368227],
+          tanks: [867, 0.49173191907236774],
+        },
+      },
+      {
+        input: "Easy easy EASY",
+        expected: { easy: [269, 1.0] },
+      },
+      {
+        input: "Easy easy care",
+        expected: {
+          easy: [269, 0.8795205218806832],
+          care: [153, 0.4758609582543317],
+        },
+      },
+      {
+        input: "easy care",
+        expected: {
+          easy: [269, 0.6786999710383944],
+          care: [153, 0.7344156515982504],
+        },
+      },
+      {
+        input: "这个空间故意留空。",
+        expected: {
+          /* This space is left intentionally blank. */
+        },
+      },
+    ];
+    let checkTokenGeneration = tc => {
+      describe(`${tc.input} should have only vocabulary tokens`, () => {
+        let actual = toksToTfIdfVector(tokenize(tc.input), vocab_idfs);
+
+        it(`${tc.input} should generate exactly ${Object.keys(
+          tc.expected
+        )}`, () => {
+          let seen = {};
+          Object.keys(actual).forEach(actualTok => {
+            assert.isTrue(actualTok in tc.expected);
+            seen[actualTok] = true;
+          });
+          Object.keys(tc.expected).forEach(expectedTok => {
+            assert.isTrue(expectedTok in seen);
+          });
+        });
+
+        it(`${tc.input} should have the correct token ids`, () => {
+          Object.keys(actual).forEach(actualTok => {
+            assert.equal(tc.expected[actualTok][0], actual[actualTok][0]);
+          });
+        });
+      });
+    };
+
+    let checkTfIdfVector = tc => {
+      let actual = toksToTfIdfVector(tokenize(tc.input), vocab_idfs);
+      it(`${tc.input} should have the correct tf-idf`, () => {
+        Object.keys(actual).forEach(actualTok => {
+          let delta = Math.abs(
+            tc.expected[actualTok][1] - actual[actualTok][1]
+          );
+          assert.isTrue(delta <= EPSILON);
+        });
+      });
+    };
+
+    // run the tests
+    for (let i = 0; i < testCases.length; i++) {
+      checkTokenGeneration(testCases[i]);
+      checkTfIdfVector(testCases[i]);
+    }
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/PrefsFeed.test.js b/browser/components/newtab/test/unit/lib/PrefsFeed.test.js
new file mode 100644
index 0000000000..498c7198ab
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/PrefsFeed.test.js
@@ -0,0 +1,357 @@
+import {
+  actionCreators as ac,
+  actionTypes as at,
+} from "common/Actions.sys.mjs";
+import { GlobalOverrider } from "test/unit/utils";
+import { PrefsFeed } from "lib/PrefsFeed.sys.mjs";
+
+let overrider = new GlobalOverrider();
+
+describe("PrefsFeed", () => {
+  let feed;
+  let FAKE_PREFS;
+  let sandbox;
+  let ServicesStub;
+  beforeEach(() => {
+    sandbox = sinon.createSandbox();
+    FAKE_PREFS = new Map([
+      ["foo", 1],
+      ["bar", 2],
+      ["baz", { value: 1, skipBroadcast: true }],
+      ["qux", { value: 1, skipBroadcast: true, alsoToPreloaded: true }],
+    ]);
+    feed = new PrefsFeed(FAKE_PREFS);
+    const storage = {
+      getAll: sandbox.stub().resolves(),
+      set: sandbox.stub().resolves(),
+    };
+    ServicesStub = {
+      prefs: {
+        clearUserPref: sinon.spy(),
+        getStringPref: sinon.spy(),
+        getIntPref: sinon.spy(),
+        getBoolPref: sinon.spy(),
+      },
+      obs: {
+        removeObserver: sinon.spy(),
+        addObserver: sinon.spy(),
+      },
+    };
+    sinon.spy(feed, "_setPref");
+    feed.store = {
+      dispatch: sinon.spy(),
+      getState() {
+        return this.state;
+      },
+      dbStorage: { getDbTable: sandbox.stub().returns(storage) },
+    };
+    // Setup for tests that don't call `init`
+    feed._storage = storage;
+    feed._prefs = {
+      get: sinon.spy(item => FAKE_PREFS.get(item)),
+      set: sinon.spy((name, value) => FAKE_PREFS.set(name, value)),
+      observe: sinon.spy(),
+      observeBranch: sinon.spy(),
+      ignore: sinon.spy(),
+      ignoreBranch: sinon.spy(),
+      reset: sinon.stub(),
+      _branchStr: "branch.str.",
+    };
+    overrider.set({
+      PrivateBrowsingUtils: { enabled: true },
+      Services: ServicesStub,
+    });
+  });
+  afterEach(() => {
+    overrider.restore();
+    sandbox.restore();
+  });
+
+  it("should set a pref when a SET_PREF action is received", () => {
+    feed.onAction(ac.SetPref("foo", 2));
+    assert.calledWith(feed._prefs.set, "foo", 2);
+  });
+  it("should call clearUserPref with action CLEAR_PREF", () => {
+    feed.onAction({ type: at.CLEAR_PREF, data: { name: "pref.test" } });
+    assert.calledWith(ServicesStub.prefs.clearUserPref, "branch.str.pref.test");
+  });
+  it("should dispatch PREFS_INITIAL_VALUES on init with pref values and .isPrivateBrowsingEnabled", () => {
+    feed.onAction({ type: at.INIT });
+    assert.calledOnce(feed.store.dispatch);
+    assert.equal(
+      feed.store.dispatch.firstCall.args[0].type,
+      at.PREFS_INITIAL_VALUES
+    );
+    const [{ data }] = feed.store.dispatch.firstCall.args;
+    assert.equal(data.foo, 1);
+    assert.equal(data.bar, 2);
+    assert.isTrue(data.isPrivateBrowsingEnabled);
+  });
+  it("should dispatch PREFS_INITIAL_VALUES with a .featureConfig", () => {
+    sandbox.stub(global.NimbusFeatures.newtab, "getAllVariables").returns({
+      prefsButtonIcon: "icon-foo",
+    });
+    feed.onAction({ type: at.INIT });
+    assert.equal(
+      feed.store.dispatch.firstCall.args[0].type,
+      at.PREFS_INITIAL_VALUES
+    );
+    const [{ data }] = feed.store.dispatch.firstCall.args;
+    assert.deepEqual(data.featureConfig, { prefsButtonIcon: "icon-foo" });
+  });
+  it("should dispatch PREFS_INITIAL_VALUES with an empty object if no experiment is returned", () => {
+    sandbox.stub(global.NimbusFeatures.newtab, "getAllVariables").returns(null);
+    feed.onAction({ type: at.INIT });
+    assert.equal(
+      feed.store.dispatch.firstCall.args[0].type,
+      at.PREFS_INITIAL_VALUES
+    );
+    const [{ data }] = feed.store.dispatch.firstCall.args;
+    assert.deepEqual(data.featureConfig, {});
+  });
+  it("should add one branch observer on init", () => {
+    feed.onAction({ type: at.INIT });
+    assert.calledOnce(feed._prefs.observeBranch);
+    assert.calledWith(feed._prefs.observeBranch, feed);
+  });
+  it("should initialise the storage on init", () => {
+    feed.init();
+
+    assert.calledOnce(feed.store.dbStorage.getDbTable);
+    assert.calledWithExactly(feed.store.dbStorage.getDbTable, "sectionPrefs");
+  });
+  it("should handle region on init", () => {
+    feed.init();
+    assert.equal(feed.geo, "US");
+  });
+  it("should add region observer on init", () => {
+    sandbox.stub(global.Region, "home").get(() => "");
+    feed.init();
+    assert.equal(feed.geo, "");
+    assert.calledWith(
+      ServicesStub.obs.addObserver,
+      feed,
+      global.Region.REGION_TOPIC
+    );
+  });
+  it("should remove the branch observer on uninit", () => {
+    feed.onAction({ type: at.UNINIT });
+    assert.calledOnce(feed._prefs.ignoreBranch);
+    assert.calledWith(feed._prefs.ignoreBranch, feed);
+  });
+  it("should call removeObserver", () => {
+    feed.geo = "";
+    feed.uninit();
+    assert.calledWith(
+      ServicesStub.obs.removeObserver,
+      feed,
+      global.Region.REGION_TOPIC
+    );
+  });
+  it("should send a PREF_CHANGED action when onPrefChanged is called", () => {
+    feed.onPrefChanged("foo", 2);
+    assert.calledWith(
+      feed.store.dispatch,
+      ac.BroadcastToContent({
+        type: at.PREF_CHANGED,
+        data: { name: "foo", value: 2 },
+      })
+    );
+  });
+  it("should send a PREF_CHANGED actions when onPocketExperimentUpdated is called", () => {
+    sandbox
+      .stub(global.NimbusFeatures.pocketNewtab, "getAllVariables")
+      .returns({
+        prefsButtonIcon: "icon-new",
+      });
+    feed.onPocketExperimentUpdated();
+    assert.calledWith(
+      feed.store.dispatch,
+      ac.BroadcastToContent({
+        type: at.PREF_CHANGED,
+        data: {
+          name: "pocketConfig",
+          value: {
+            prefsButtonIcon: "icon-new",
+          },
+        },
+      })
+    );
+  });
+  it("should not send a PREF_CHANGED actions when onPocketExperimentUpdated is called during startup", () => {
+    sandbox
+      .stub(global.NimbusFeatures.pocketNewtab, "getAllVariables")
+      .returns({
+        prefsButtonIcon: "icon-new",
+      });
+    feed.onPocketExperimentUpdated({}, "feature-experiment-loaded");
+    assert.notCalled(feed.store.dispatch);
+    feed.onPocketExperimentUpdated({}, "feature-rollout-loaded");
+    assert.notCalled(feed.store.dispatch);
+  });
+  it("should send a PREF_CHANGED actions when onExperimentUpdated is called", () => {
+    sandbox.stub(global.NimbusFeatures.newtab, "getAllVariables").returns({
+      prefsButtonIcon: "icon-new",
+    });
+    feed.onExperimentUpdated();
+    assert.calledWith(
+      feed.store.dispatch,
+      ac.BroadcastToContent({
+        type: at.PREF_CHANGED,
+        data: {
+          name: "featureConfig",
+          value: {
+            prefsButtonIcon: "icon-new",
+          },
+        },
+      })
+    );
+  });
+
+  it("should remove all events on removeListeners", () => {
+    feed.geo = "";
+    sandbox.spy(global.NimbusFeatures.pocketNewtab, "offUpdate");
+    sandbox.spy(global.NimbusFeatures.newtab, "offUpdate");
+    feed.removeListeners();
+    assert.calledWith(
+      global.NimbusFeatures.pocketNewtab.offUpdate,
+      feed.onPocketExperimentUpdated
+    );
+    assert.calledWith(
+      global.NimbusFeatures.newtab.offUpdate,
+      feed.onExperimentUpdated
+    );
+    assert.calledWith(
+      ServicesStub.obs.removeObserver,
+      feed,
+      global.Region.REGION_TOPIC
+    );
+  });
+
+  it("should set storage pref on UPDATE_SECTION_PREFS", async () => {
+    await feed.onAction({
+      type: at.UPDATE_SECTION_PREFS,
+      data: { id: "topsites", value: { collapsed: false } },
+    });
+    assert.calledWith(feed._storage.set, "topsites", { collapsed: false });
+  });
+  it("should set storage pref with section prefix on UPDATE_SECTION_PREFS", async () => {
+    await feed.onAction({
+      type: at.UPDATE_SECTION_PREFS,
+      data: { id: "topstories", value: { collapsed: false } },
+    });
+    assert.calledWith(feed._storage.set, "feeds.section.topstories", {
+      collapsed: false,
+    });
+  });
+  it("should catch errors on UPDATE_SECTION_PREFS", async () => {
+    feed._storage.set.throws(new Error("foo"));
+    assert.doesNotThrow(async () => {
+      await feed.onAction({
+        type: at.UPDATE_SECTION_PREFS,
+        data: { id: "topstories", value: { collapsed: false } },
+      });
+    });
+  });
+  it("should send OnlyToMain pref update if config for pref has skipBroadcast: true", async () => {
+    feed.onPrefChanged("baz", { value: 2, skipBroadcast: true });
+    assert.calledWith(
+      feed.store.dispatch,
+      ac.OnlyToMain({
+        type: at.PREF_CHANGED,
+        data: { name: "baz", value: { value: 2, skipBroadcast: true } },
+      })
+    );
+  });
+  it("should send AlsoToPreloaded pref update if config for pref has skipBroadcast: true and alsoToPreloaded: true", async () => {
+    feed.onPrefChanged("qux", {
+      value: 2,
+      skipBroadcast: true,
+      alsoToPreloaded: true,
+    });
+    assert.calledWith(
+      feed.store.dispatch,
+      ac.AlsoToPreloaded({
+        type: at.PREF_CHANGED,
+        data: {
+          name: "qux",
+          value: { value: 2, skipBroadcast: true, alsoToPreloaded: true },
+        },
+      })
+    );
+  });
+  describe("#observe", () => {
+    it("should call dispatch from observe", () => {
+      feed.observe(undefined, global.Region.REGION_TOPIC);
+      assert.calledOnce(feed.store.dispatch);
+    });
+  });
+  describe("#_setStringPref", () => {
+    it("should call _setPref and getStringPref from _setStringPref", () => {
+      feed._setStringPref({}, "fake.pref", "default");
+      assert.calledOnce(feed._setPref);
+      assert.calledWith(
+        feed._setPref,
+        { "fake.pref": undefined },
+        "fake.pref",
+        "default"
+      );
+      assert.calledOnce(ServicesStub.prefs.getStringPref);
+      assert.calledWith(
+        ServicesStub.prefs.getStringPref,
+        "browser.newtabpage.activity-stream.fake.pref",
+        "default"
+      );
+    });
+  });
+  describe("#_setBoolPref", () => {
+    it("should call _setPref and getBoolPref from _setBoolPref", () => {
+      feed._setBoolPref({}, "fake.pref", false);
+      assert.calledOnce(feed._setPref);
+      assert.calledWith(
+        feed._setPref,
+        { "fake.pref": undefined },
+        "fake.pref",
+        false
+      );
+      assert.calledOnce(ServicesStub.prefs.getBoolPref);
+      assert.calledWith(
+        ServicesStub.prefs.getBoolPref,
+        "browser.newtabpage.activity-stream.fake.pref",
+        false
+      );
+    });
+  });
+  describe("#_setIntPref", () => {
+    it("should call _setPref and getIntPref from _setIntPref", () => {
+      feed._setIntPref({}, "fake.pref", 1);
+      assert.calledOnce(feed._setPref);
+      assert.calledWith(
+        feed._setPref,
+        { "fake.pref": undefined },
+        "fake.pref",
+        1
+      );
+      assert.calledOnce(ServicesStub.prefs.getIntPref);
+      assert.calledWith(
+        ServicesStub.prefs.getIntPref,
+        "browser.newtabpage.activity-stream.fake.pref",
+        1
+      );
+    });
+  });
+  describe("#_setPref", () => {
+    it("should set pref value with _setPref", () => {
+      const getPrefFunctionSpy = sinon.spy();
+      const values = {};
+      feed._setPref(values, "fake.pref", "default", getPrefFunctionSpy);
+      assert.deepEqual(values, { "fake.pref": undefined });
+      assert.calledOnce(getPrefFunctionSpy);
+      assert.calledWith(
+        getPrefFunctionSpy,
+        "browser.newtabpage.activity-stream.fake.pref",
+        "default"
+      );
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/RecommendationProvider.test.js b/browser/components/newtab/test/unit/lib/RecommendationProvider.test.js
new file mode 100644
index 0000000000..9e68f4869a
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/RecommendationProvider.test.js
@@ -0,0 +1,331 @@
+import {
+  actionCreators as ac,
+  actionTypes as at,
+} from "common/Actions.sys.mjs";
+import { RecommendationProvider } from "lib/RecommendationProvider.sys.mjs";
+import { combineReducers, createStore } from "redux";
+import { reducers } from "common/Reducers.sys.mjs";
+import { GlobalOverrider } from "test/unit/utils";
+
+import { PersonalityProvider } from "lib/PersonalityProvider/PersonalityProvider.sys.mjs";
+import { PersistentCache } from "lib/PersistentCache.sys.mjs";
+
+const PREF_PERSONALIZATION_ENABLED = "discoverystream.personalization.enabled";
+const PREF_PERSONALIZATION_MODEL_KEYS =
+  "discoverystream.personalization.modelKeys";
+describe("RecommendationProvider", () => {
+  let feed;
+  let sandbox;
+  let clock;
+  let globals;
+
+  beforeEach(() => {
+    globals = new GlobalOverrider();
+    globals.set({
+      PersistentCache,
+      PersonalityProvider,
+    });
+
+    sandbox = sinon.createSandbox();
+    clock = sinon.useFakeTimers();
+    feed = new RecommendationProvider();
+    feed.store = createStore(combineReducers(reducers), {});
+  });
+
+  afterEach(() => {
+    sandbox.restore();
+    clock.restore();
+    globals.restore();
+  });
+
+  describe("#setProvider", () => {
+    it("should setup proper provider with modelKeys", async () => {
+      feed.setProvider();
+
+      assert.equal(feed.provider.modelKeys, undefined);
+
+      feed.provider = null;
+      feed._modelKeys = "1234";
+
+      feed.setProvider();
+
+      assert.equal(feed.provider.modelKeys, "1234");
+      feed._modelKeys = "12345";
+
+      // Calling it again should not rebuild the provider.
+      feed.setProvider();
+      assert.equal(feed.provider.modelKeys, "1234");
+    });
+  });
+
+  describe("#calculateItemRelevanceScore", () => {
+    it("should use personalized score with provider", async () => {
+      const item = {};
+      feed.provider = {
+        calculateItemRelevanceScore: async () => 0.5,
+      };
+      await feed.calculateItemRelevanceScore(item);
+      assert.equal(item.score, 0.5);
+    });
+  });
+
+  describe("#teardown", () => {
+    it("should call provider.teardown ", () => {
+      sandbox.stub(global.Services.obs, "removeObserver").returns();
+      feed.loaded = true;
+      feed.provider = {
+        teardown: sandbox.stub().resolves(),
+      };
+      feed.teardown();
+      assert.calledOnce(feed.provider.teardown);
+      assert.calledOnce(global.Services.obs.removeObserver);
+      assert.calledWith(global.Services.obs.removeObserver, feed, "idle-daily");
+    });
+  });
+
+  describe("#resetState", () => {
+    it("should null affinityProviderV2 and affinityProvider", () => {
+      feed._modelKeys = {};
+      feed.provider = {};
+
+      feed.resetState();
+
+      assert.equal(feed._modelKeys, null);
+      assert.equal(feed.provider, null);
+    });
+  });
+
+  describe("#onAction: DISCOVERY_STREAM_CONFIG_CHANGE", () => {
+    it("should call teardown, resetState, and setVersion", async () => {
+      sandbox.spy(feed, "teardown");
+      sandbox.spy(feed, "resetState");
+      feed.onAction({
+        type: at.DISCOVERY_STREAM_CONFIG_CHANGE,
+      });
+      assert.calledOnce(feed.teardown);
+      assert.calledOnce(feed.resetState);
+    });
+  });
+
+  describe("#onAction: PREF_CHANGED", () => {
+    beforeEach(() => {
+      sandbox.spy(feed.store, "dispatch");
+    });
+    it("should dispatch to DISCOVERY_STREAM_CONFIG_RESET PREF_PERSONALIZATION_MODEL_KEYS", async () => {
+      feed.onAction({
+        type: at.PREF_CHANGED,
+        data: {
+          name: PREF_PERSONALIZATION_MODEL_KEYS,
+        },
+      });
+
+      assert.calledWith(
+        feed.store.dispatch,
+        ac.BroadcastToContent({
+          type: at.DISCOVERY_STREAM_CONFIG_RESET,
+        })
+      );
+    });
+  });
+
+  describe("#personalizationOverride", () => {
+    it("should dispatch setPref", async () => {
+      sandbox.spy(feed.store, "dispatch");
+      feed.store.getState = () => ({
+        Prefs: {
+          values: {
+            "discoverystream.personalization.enabled": true,
+          },
+        },
+      });
+
+      feed.personalizationOverride(true);
+
+      assert.calledWithMatch(feed.store.dispatch, {
+        data: {
+          name: "discoverystream.personalization.override",
+          value: true,
+        },
+        type: at.SET_PREF,
+      });
+    });
+    it("should dispatch CLEAR_PREF", async () => {
+      sandbox.spy(feed.store, "dispatch");
+      feed.store.getState = () => ({
+        Prefs: {
+          values: {
+            "discoverystream.personalization.enabled": true,
+            "discoverystream.personalization.override": true,
+          },
+        },
+      });
+
+      feed.personalizationOverride(false);
+
+      assert.calledWithMatch(feed.store.dispatch, {
+        data: {
+          name: "discoverystream.personalization.override",
+        },
+        type: at.CLEAR_PREF,
+      });
+    });
+  });
+
+  describe("#onAction: DISCOVERY_STREAM_DEV_IDLE_DAILY", () => {
+    it("should trigger idle-daily observer", async () => {
+      sandbox.stub(global.Services.obs, "notifyObservers").returns();
+      await feed.onAction({
+        type: at.DISCOVERY_STREAM_DEV_IDLE_DAILY,
+      });
+      assert.calledWith(
+        global.Services.obs.notifyObservers,
+        null,
+        "idle-daily"
+      );
+    });
+  });
+
+  describe("#onAction: INIT", () => {
+    it("should ", async () => {
+      sandbox.stub(feed, "enable").returns();
+      await feed.onAction({
+        type: at.INIT,
+      });
+      assert.calledOnce(feed.enable);
+      assert.calledWith(feed.enable, true);
+    });
+  });
+
+  describe("#onAction: DISCOVERY_STREAM_PERSONALIZATION_OVERRIDE", () => {
+    it("should ", async () => {
+      sandbox.stub(feed, "personalizationOverride").returns();
+      await feed.onAction({
+        type: at.DISCOVERY_STREAM_PERSONALIZATION_OVERRIDE,
+        data: { override: true },
+      });
+      assert.calledOnce(feed.personalizationOverride);
+      assert.calledWith(feed.personalizationOverride, true);
+    });
+  });
+
+  describe("#loadPersonalizationScoresCache", () => {
+    it("should create a personalization provider from cached scores", async () => {
+      sandbox.spy(feed.store, "dispatch");
+      sandbox.spy(feed.cache, "set");
+      feed.provider = {
+        init: async () => {},
+        getScores: () => "scores",
+      };
+      feed.store.getState = () => ({
+        Prefs: {
+          values: {
+            pocketConfig: {
+              recsPersonalized: true,
+              spocsPersonalized: true,
+            },
+            "discoverystream.personalization.enabled": true,
+            "feeds.section.topstories": true,
+            "feeds.system.topstories": true,
+          },
+        },
+      });
+      const fakeCache = {
+        personalization: {
+          scores: 123,
+          _timestamp: 456,
+        },
+      };
+      sandbox.stub(feed.cache, "get").returns(Promise.resolve(fakeCache));
+
+      await feed.loadPersonalizationScoresCache();
+
+      assert.equal(feed.personalizationLastUpdated, 456);
+    });
+  });
+
+  describe("#updatePersonalizationScores", () => {
+    beforeEach(() => {
+      sandbox.spy(feed.store, "dispatch");
+      sandbox.spy(feed.cache, "set");
+      sandbox.spy(feed, "setProvider");
+      feed.provider = {
+        init: async () => {},
+        getScores: () => "scores",
+      };
+    });
+    it("should update provider on updatePersonalizationScores", async () => {
+      feed.store.getState = () => ({
+        Prefs: {
+          values: {
+            pocketConfig: {
+              recsPersonalized: true,
+              spocsPersonalized: true,
+            },
+            "discoverystream.personalization.enabled": true,
+            "feeds.section.topstories": true,
+            "feeds.system.topstories": true,
+          },
+        },
+      });
+
+      await feed.updatePersonalizationScores();
+
+      assert.calledWith(
+        feed.store.dispatch,
+        ac.BroadcastToContent({
+          type: at.DISCOVERY_STREAM_PERSONALIZATION_LAST_UPDATED,
+          data: {
+            lastUpdated: 0,
+          },
+        })
+      );
+      assert.calledWith(feed.cache.set, "personalization", {
+        scores: "scores",
+        _timestamp: 0,
+      });
+    });
+    it("should not update provider on updatePersonalizationScores", async () => {
+      feed.store.getState = () => ({
+        Prefs: {
+          values: {
+            "discoverystream.spocs.personalized": true,
+            "discoverystream.recs.personalized": true,
+            "discoverystream.personalization.enabled": false,
+          },
+        },
+      });
+      await feed.updatePersonalizationScores();
+
+      assert.notCalled(feed.setProvider);
+    });
+  });
+
+  describe("#onAction: DISCOVERY_STREAM_PERSONALIZATION_TOGGLE", () => {
+    it("should fire SET_PREF with enabled", async () => {
+      sandbox.spy(feed.store, "dispatch");
+      feed.store.getState = () => ({
+        Prefs: {
+          values: {
+            [PREF_PERSONALIZATION_ENABLED]: false,
+          },
+        },
+      });
+
+      await feed.onAction({
+        type: at.DISCOVERY_STREAM_PERSONALIZATION_TOGGLE,
+      });
+      assert.calledWith(
+        feed.store.dispatch,
+        ac.SetPref(PREF_PERSONALIZATION_ENABLED, true)
+      );
+    });
+  });
+
+  describe("#observe", () => {
+    it("should call updatePersonalizationScores on idle daily", async () => {
+      sandbox.stub(feed, "updatePersonalizationScores").returns();
+      feed.observe(null, "idle-daily");
+      assert.calledOnce(feed.updatePersonalizationScores);
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/Screenshots.test.js b/browser/components/newtab/test/unit/lib/Screenshots.test.js
new file mode 100644
index 0000000000..a03f06890d
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/Screenshots.test.js
@@ -0,0 +1,209 @@
+"use strict";
+import { GlobalOverrider } from "test/unit/utils";
+import { Screenshots } from "lib/Screenshots.sys.mjs";
+
+const URL = "foo.com";
+const FAKE_THUMBNAIL_PATH = "fake/path/thumb.jpg";
+const FAKE_THUMBNAIL_THUMB =
+  "moz-page-thumb://thumbnail?url=http%3A%2F%2Ffoo.com%2F";
+
+describe("Screenshots", () => {
+  let globals;
+  let sandbox;
+  let fakeServices;
+  let testFile;
+
+  beforeEach(() => {
+    globals = new GlobalOverrider();
+    sandbox = globals.sandbox;
+    fakeServices = {
+      wm: {
+        getEnumerator() {
+          return Array(10);
+        },
+      },
+    };
+    globals.set("BackgroundPageThumbs", {
+      captureIfMissing: sandbox.spy(() => Promise.resolve()),
+    });
+    globals.set("PageThumbs", {
+      _store: sandbox.stub(),
+      getThumbnailPath: sandbox.spy(() => FAKE_THUMBNAIL_PATH),
+      getThumbnailURL: sandbox.spy(() => FAKE_THUMBNAIL_THUMB),
+    });
+    globals.set("PrivateBrowsingUtils", {
+      isWindowPrivate: sandbox.spy(() => false),
+    });
+    testFile = { size: 1 };
+    globals.set("Services", fakeServices);
+    globals.set(
+      "fetch",
+      sandbox.spy(() =>
+        Promise.resolve({ blob: () => Promise.resolve(testFile) })
+      )
+    );
+  });
+  afterEach(() => {
+    globals.restore();
+  });
+
+  describe("#getScreenshotForURL", () => {
+    it("should call BackgroundPageThumbs.captureIfMissing with the correct url", async () => {
+      await Screenshots.getScreenshotForURL(URL);
+      assert.calledWith(global.BackgroundPageThumbs.captureIfMissing, URL);
+    });
+    it("should call PageThumbs.getThumbnailPath with the correct url", async () => {
+      globals.set("gPrivilegedAboutProcessEnabled", false);
+      await Screenshots.getScreenshotForURL(URL);
+      assert.calledWith(global.PageThumbs.getThumbnailPath, URL);
+    });
+    it("should call fetch", async () => {
+      await Screenshots.getScreenshotForURL(URL);
+      assert.calledOnce(global.fetch);
+    });
+    it("should have the necessary keys in the response object", async () => {
+      const screenshot = await Screenshots.getScreenshotForURL(URL);
+
+      assert.notEqual(screenshot.path, undefined);
+      assert.notEqual(screenshot.data, undefined);
+    });
+    it("should get null if something goes wrong", async () => {
+      globals.set("BackgroundPageThumbs", {
+        captureIfMissing: () =>
+          Promise.reject(new Error("Cannot capture thumbnail")),
+      });
+
+      const screenshot = await Screenshots.getScreenshotForURL(URL);
+
+      assert.calledOnce(global.PageThumbs._store);
+      assert.equal(screenshot, null);
+    });
+    it("should get direct thumbnail url for privileged process", async () => {
+      globals.set("gPrivilegedAboutProcessEnabled", true);
+      await Screenshots.getScreenshotForURL(URL);
+      assert.calledWith(global.PageThumbs.getThumbnailURL, URL);
+    });
+    it("should get null without storing if existing thumbnail is empty", async () => {
+      testFile.size = 0;
+
+      const screenshot = await Screenshots.getScreenshotForURL(URL);
+
+      assert.notCalled(global.PageThumbs._store);
+      assert.equal(screenshot, null);
+    });
+  });
+
+  describe("#maybeCacheScreenshot", () => {
+    let link;
+    beforeEach(() => {
+      link = {
+        __sharedCache: {
+          updateLink: (prop, val) => {
+            link[prop] = val;
+          },
+        },
+      };
+    });
+    it("should call getScreenshotForURL", () => {
+      sandbox.stub(Screenshots, "getScreenshotForURL");
+      sandbox.stub(Screenshots, "_shouldGetScreenshots").returns(true);
+      Screenshots.maybeCacheScreenshot(
+        link,
+        "mozilla.com",
+        "image",
+        sinon.stub()
+      );
+
+      assert.calledOnce(Screenshots.getScreenshotForURL);
+      assert.calledWithExactly(Screenshots.getScreenshotForURL, "mozilla.com");
+    });
+    it("should not call getScreenshotForURL twice if a fetch is in progress", () => {
+      sandbox
+        .stub(Screenshots, "getScreenshotForURL")
+        .returns(new Promise(() => {}));
+      sandbox.stub(Screenshots, "_shouldGetScreenshots").returns(true);
+      Screenshots.maybeCacheScreenshot(
+        link,
+        "mozilla.com",
+        "image",
+        sinon.stub()
+      );
+      Screenshots.maybeCacheScreenshot(
+        link,
+        "mozilla.org",
+        "image",
+        sinon.stub()
+      );
+
+      assert.calledOnce(Screenshots.getScreenshotForURL);
+      assert.calledWithExactly(Screenshots.getScreenshotForURL, "mozilla.com");
+    });
+    it("should not call getScreenshotsForURL if property !== undefined", async () => {
+      sandbox
+        .stub(Screenshots, "getScreenshotForURL")
+        .returns(Promise.resolve(null));
+      sandbox.stub(Screenshots, "_shouldGetScreenshots").returns(true);
+      await Screenshots.maybeCacheScreenshot(
+        link,
+        "mozilla.com",
+        "image",
+        sinon.stub()
+      );
+      await Screenshots.maybeCacheScreenshot(
+        link,
+        "mozilla.org",
+        "image",
+        sinon.stub()
+      );
+
+      assert.calledOnce(Screenshots.getScreenshotForURL);
+      assert.calledWithExactly(Screenshots.getScreenshotForURL, "mozilla.com");
+    });
+    it("should check if we are in private browsing before getting screenshots", async () => {
+      sandbox.stub(Screenshots, "_shouldGetScreenshots").returns(true);
+      await Screenshots.maybeCacheScreenshot(
+        link,
+        "mozilla.com",
+        "image",
+        sinon.stub()
+      );
+
+      assert.calledOnce(Screenshots._shouldGetScreenshots);
+    });
+    it("should not get a screenshot if we are in private browsing", async () => {
+      sandbox.stub(Screenshots, "getScreenshotForURL");
+      sandbox.stub(Screenshots, "_shouldGetScreenshots").returns(false);
+      await Screenshots.maybeCacheScreenshot(
+        link,
+        "mozilla.com",
+        "image",
+        sinon.stub()
+      );
+
+      assert.notCalled(Screenshots.getScreenshotForURL);
+    });
+  });
+
+  describe("#_shouldGetScreenshots", () => {
+    beforeEach(() => {
+      let more = 2;
+      sandbox
+        .stub(global.Services.wm, "getEnumerator")
+        .callsFake(() => Array(Math.max(more--, 0)));
+    });
+    it("should use private browsing utils to determine if a window is private", () => {
+      Screenshots._shouldGetScreenshots();
+      assert.calledOnce(global.PrivateBrowsingUtils.isWindowPrivate);
+    });
+    it("should return true if there exists at least 1 non-private window", () => {
+      assert.isTrue(Screenshots._shouldGetScreenshots());
+    });
+    it("should return false if there exists private windows", () => {
+      global.PrivateBrowsingUtils = {
+        isWindowPrivate: sandbox.spy(() => true),
+      };
+      assert.isFalse(Screenshots._shouldGetScreenshots());
+      assert.calledTwice(global.PrivateBrowsingUtils.isWindowPrivate);
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/SectionsManager.test.js b/browser/components/newtab/test/unit/lib/SectionsManager.test.js
new file mode 100644
index 0000000000..b3a9abd70c
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/SectionsManager.test.js
@@ -0,0 +1,897 @@
+"use strict";
+import {
+  actionCreators as ac,
+  actionTypes as at,
+  CONTENT_MESSAGE_TYPE,
+  MAIN_MESSAGE_TYPE,
+  PRELOAD_MESSAGE_TYPE,
+} from "common/Actions.sys.mjs";
+import { EventEmitter, GlobalOverrider } from "test/unit/utils";
+import { SectionsFeed, SectionsManager } from "lib/SectionsManager.sys.mjs";
+
+const FAKE_ID = "FAKE_ID";
+const FAKE_OPTIONS = { icon: "FAKE_ICON", title: "FAKE_TITLE" };
+const FAKE_ROWS = [
+  { url: "1.example.com", type: "bookmark" },
+  { url: "2.example.com", type: "pocket" },
+  { url: "3.example.com", type: "history" },
+];
+const FAKE_TRENDING_ROWS = [{ url: "bar", type: "trending" }];
+const FAKE_URL = "2.example.com";
+const FAKE_CARD_OPTIONS = { title: "Some fake title" };
+
+describe("SectionsManager", () => {
+  let globals;
+  let fakeServices;
+  let fakePlacesUtils;
+  let sandbox;
+  let storage;
+
+  beforeEach(async () => {
+    sandbox = sinon.createSandbox();
+    globals = new GlobalOverrider();
+    fakeServices = {
+      prefs: {
+        getBoolPref: sandbox.stub(),
+        addObserver: sandbox.stub(),
+        removeObserver: sandbox.stub(),
+      },
+    };
+    fakePlacesUtils = {
+      history: { update: sinon.stub(), insert: sinon.stub() },
+    };
+    globals.set({
+      Services: fakeServices,
+      PlacesUtils: fakePlacesUtils,
+      NimbusFeatures: {
+        newtab: { getAllVariables: sandbox.stub() },
+        pocketNewtab: { getAllVariables: sandbox.stub() },
+      },
+    });
+    // Redecorate SectionsManager to remove any listeners that have been added
+    EventEmitter.decorate(SectionsManager);
+    storage = {
+      get: sandbox.stub().resolves(),
+      set: sandbox.stub().resolves(),
+    };
+  });
+
+  afterEach(() => {
+    globals.restore();
+    sandbox.restore();
+  });
+
+  describe("#init", () => {
+    it("should initialise the sections map with the built in sections", async () => {
+      SectionsManager.sections.clear();
+      SectionsManager.initialized = false;
+      await SectionsManager.init({}, storage);
+      assert.equal(SectionsManager.sections.size, 2);
+      assert.ok(SectionsManager.sections.has("topstories"));
+      assert.ok(SectionsManager.sections.has("highlights"));
+    });
+    it("should set .initialized to true", async () => {
+      SectionsManager.sections.clear();
+      SectionsManager.initialized = false;
+      await SectionsManager.init({}, storage);
+      assert.ok(SectionsManager.initialized);
+    });
+    it("should add observer for context menu prefs", async () => {
+      SectionsManager.CONTEXT_MENU_PREFS = { MENU_ITEM: "MENU_ITEM_PREF" };
+      await SectionsManager.init({}, storage);
+      assert.calledOnce(fakeServices.prefs.addObserver);
+      assert.calledWith(
+        fakeServices.prefs.addObserver,
+        "MENU_ITEM_PREF",
+        SectionsManager
+      );
+    });
+    it("should save the reference to `storage` passed in", async () => {
+      await SectionsManager.init({}, storage);
+
+      assert.equal(SectionsManager._storage, storage);
+    });
+  });
+  describe("#uninit", () => {
+    it("should remove observer for context menu prefs", () => {
+      SectionsManager.CONTEXT_MENU_PREFS = { MENU_ITEM: "MENU_ITEM_PREF" };
+      SectionsManager.initialized = true;
+      SectionsManager.uninit();
+      assert.calledOnce(fakeServices.prefs.removeObserver);
+      assert.calledWith(
+        fakeServices.prefs.removeObserver,
+        "MENU_ITEM_PREF",
+        SectionsManager
+      );
+      assert.isFalse(SectionsManager.initialized);
+    });
+  });
+  describe("#addBuiltInSection", () => {
+    it("should not report an error if options is undefined", async () => {
+      globals.sandbox.spy(global.console, "error");
+      SectionsManager._storage.get = sandbox.stub().returns(Promise.resolve());
+      await SectionsManager.addBuiltInSection(
+        "feeds.section.topstories",
+        undefined
+      );
+
+      assert.notCalled(console.error);
+    });
+    it("should report an error if options is malformed", async () => {
+      globals.sandbox.spy(global.console, "error");
+      SectionsManager._storage.get = sandbox.stub().returns(Promise.resolve());
+      await SectionsManager.addBuiltInSection(
+        "feeds.section.topstories",
+        "invalid"
+      );
+
+      assert.calledOnce(console.error);
+    });
+    it("should not throw if the indexedDB operation fails", async () => {
+      globals.sandbox.spy(global.console, "error");
+      storage.get = sandbox.stub().throws();
+      SectionsManager._storage = storage;
+
+      try {
+        await SectionsManager.addBuiltInSection("feeds.section.topstories");
+      } catch (e) {
+        assert.fail();
+      }
+
+      assert.calledOnce(storage.get);
+      assert.calledOnce(console.error);
+    });
+  });
+  describe("#updateSectionPrefs", () => {
+    it("should update the collapsed value of the section", async () => {
+      sandbox.stub(SectionsManager, "updateSection");
+      let topstories = SectionsManager.sections.get("topstories");
+      assert.isFalse(topstories.pref.collapsed);
+
+      await SectionsManager.updateSectionPrefs("topstories", {
+        collapsed: true,
+      });
+      topstories = SectionsManager.sections.get("topstories");
+
+      assert.isTrue(SectionsManager.updateSection.args[0][1].pref.collapsed);
+    });
+    it("should ignore invalid ids", async () => {
+      sandbox.stub(SectionsManager, "updateSection");
+      await SectionsManager.updateSectionPrefs("foo", { collapsed: true });
+
+      assert.notCalled(SectionsManager.updateSection);
+    });
+  });
+  describe("#addSection", () => {
+    it("should add the id to sections and emit an ADD_SECTION event", () => {
+      const spy = sinon.spy();
+      SectionsManager.on(SectionsManager.ADD_SECTION, spy);
+      SectionsManager.addSection(FAKE_ID, FAKE_OPTIONS);
+      assert.ok(SectionsManager.sections.has(FAKE_ID));
+      assert.calledOnce(spy);
+      assert.calledWith(
+        spy,
+        SectionsManager.ADD_SECTION,
+        FAKE_ID,
+        FAKE_OPTIONS
+      );
+    });
+  });
+  describe("#removeSection", () => {
+    it("should remove the id from sections and emit an REMOVE_SECTION event", () => {
+      // Ensure we start with the id in the set
+      assert.ok(SectionsManager.sections.has(FAKE_ID));
+      const spy = sinon.spy();
+      SectionsManager.on(SectionsManager.REMOVE_SECTION, spy);
+      SectionsManager.removeSection(FAKE_ID);
+      assert.notOk(SectionsManager.sections.has(FAKE_ID));
+      assert.calledOnce(spy);
+      assert.calledWith(spy, SectionsManager.REMOVE_SECTION, FAKE_ID);
+    });
+  });
+  describe("#enableSection", () => {
+    it("should call updateSection with {enabled: true}", () => {
+      sinon.spy(SectionsManager, "updateSection");
+      SectionsManager.addSection(FAKE_ID, FAKE_OPTIONS);
+      SectionsManager.enableSection(FAKE_ID);
+      assert.calledOnce(SectionsManager.updateSection);
+      assert.calledWith(
+        SectionsManager.updateSection,
+        FAKE_ID,
+        { enabled: true },
+        true
+      );
+      SectionsManager.updateSection.restore();
+    });
+    it("should emit an ENABLE_SECTION event", () => {
+      const spy = sinon.spy();
+      SectionsManager.on(SectionsManager.ENABLE_SECTION, spy);
+      SectionsManager.enableSection(FAKE_ID);
+      assert.calledOnce(spy);
+      assert.calledWith(spy, SectionsManager.ENABLE_SECTION, FAKE_ID);
+    });
+  });
+  describe("#disableSection", () => {
+    it("should call updateSection with {enabled: false, rows: [], initialized: false}", () => {
+      sinon.spy(SectionsManager, "updateSection");
+      SectionsManager.addSection(FAKE_ID, FAKE_OPTIONS);
+      SectionsManager.disableSection(FAKE_ID);
+      assert.calledOnce(SectionsManager.updateSection);
+      assert.calledWith(
+        SectionsManager.updateSection,
+        FAKE_ID,
+        { enabled: false, rows: [], initialized: false },
+        true
+      );
+      SectionsManager.updateSection.restore();
+    });
+    it("should emit a DISABLE_SECTION event", () => {
+      const spy = sinon.spy();
+      SectionsManager.on(SectionsManager.DISABLE_SECTION, spy);
+      SectionsManager.disableSection(FAKE_ID);
+      assert.calledOnce(spy);
+      assert.calledWith(spy, SectionsManager.DISABLE_SECTION, FAKE_ID);
+    });
+  });
+  describe("#updateSection", () => {
+    it("should emit an UPDATE_SECTION event with correct arguments", () => {
+      SectionsManager.addSection(FAKE_ID, FAKE_OPTIONS);
+      const spy = sinon.spy();
+      const dedupeConfigurations = [
+        { id: "topstories", dedupeFrom: ["highlights"] },
+      ];
+      SectionsManager.on(SectionsManager.UPDATE_SECTION, spy);
+      SectionsManager.updateSection(FAKE_ID, { rows: FAKE_ROWS }, true);
+      assert.calledOnce(spy);
+      assert.calledWith(
+        spy,
+        SectionsManager.UPDATE_SECTION,
+        FAKE_ID,
+        { rows: FAKE_ROWS, dedupeConfigurations },
+        true
+      );
+    });
+    it("should do nothing if the section doesn't exist", () => {
+      SectionsManager.removeSection(FAKE_ID);
+      const spy = sinon.spy();
+      SectionsManager.on(SectionsManager.UPDATE_SECTION, spy);
+      SectionsManager.updateSection(FAKE_ID, { rows: FAKE_ROWS }, true);
+      assert.notCalled(spy);
+    });
+    it("should update all sections", () => {
+      SectionsManager.sections.clear();
+      const updateSectionOrig = SectionsManager.updateSection;
+      SectionsManager.updateSection = sinon.spy();
+
+      SectionsManager.addSection("ID1", { title: "FAKE_TITLE_1" });
+      SectionsManager.addSection("ID2", { title: "FAKE_TITLE_2" });
+      SectionsManager.updateSections();
+
+      assert.calledTwice(SectionsManager.updateSection);
+      assert.calledWith(
+        SectionsManager.updateSection,
+        "ID1",
+        { title: "FAKE_TITLE_1" },
+        true
+      );
+      assert.calledWith(
+        SectionsManager.updateSection,
+        "ID2",
+        { title: "FAKE_TITLE_2" },
+        true
+      );
+      SectionsManager.updateSection = updateSectionOrig;
+    });
+    it("context menu pref change should update sections", async () => {
+      let observer;
+      const services = {
+        prefs: {
+          getBoolPref: sinon.spy(),
+          addObserver: (pref, o) => (observer = o),
+          removeObserver: sinon.spy(),
+        },
+      };
+      globals.set("Services", services);
+
+      SectionsManager.updateSections = sinon.spy();
+      SectionsManager.CONTEXT_MENU_PREFS = { MENU_ITEM: "MENU_ITEM_PREF" };
+      await SectionsManager.init({}, storage);
+      observer.observe("", "nsPref:changed", "MENU_ITEM_PREF");
+
+      assert.calledOnce(SectionsManager.updateSections);
+    });
+  });
+  describe("#_addCardTypeLinkMenuOptions", () => {
+    const addCardTypeLinkMenuOptionsOrig =
+      SectionsManager._addCardTypeLinkMenuOptions;
+    const contextMenuOptionsOrig =
+      SectionsManager.CONTEXT_MENU_OPTIONS_FOR_HIGHLIGHT_TYPES;
+    beforeEach(() => {
+      // Add a topstories section and a highlights section, with types for each card
+      SectionsManager.addSection("topstories", { FAKE_TRENDING_ROWS });
+      SectionsManager.addSection("highlights", { FAKE_ROWS });
+    });
+    it("should only call _addCardTypeLinkMenuOptions if the section update is for highlights", () => {
+      SectionsManager._addCardTypeLinkMenuOptions = sinon.spy();
+      SectionsManager.updateSection("topstories", { rows: FAKE_ROWS }, false);
+      assert.notCalled(SectionsManager._addCardTypeLinkMenuOptions);
+
+      SectionsManager.updateSection("highlights", { rows: FAKE_ROWS }, false);
+      assert.calledWith(SectionsManager._addCardTypeLinkMenuOptions, FAKE_ROWS);
+    });
+    it("should only call _addCardTypeLinkMenuOptions if the section update has rows", () => {
+      SectionsManager._addCardTypeLinkMenuOptions = sinon.spy();
+      SectionsManager.updateSection("highlights", {}, false);
+      assert.notCalled(SectionsManager._addCardTypeLinkMenuOptions);
+    });
+    it("should assign the correct context menu options based on the type of highlight", () => {
+      SectionsManager._addCardTypeLinkMenuOptions =
+        addCardTypeLinkMenuOptionsOrig;
+
+      SectionsManager.updateSection("highlights", { rows: FAKE_ROWS }, false);
+      const highlights = SectionsManager.sections.get("highlights").FAKE_ROWS;
+
+      // FAKE_ROWS was added in the following order: bookmark, pocket, history
+      assert.deepEqual(
+        highlights[0].contextMenuOptions,
+        SectionsManager.CONTEXT_MENU_OPTIONS_FOR_HIGHLIGHT_TYPES.bookmark
+      );
+      assert.deepEqual(
+        highlights[1].contextMenuOptions,
+        SectionsManager.CONTEXT_MENU_OPTIONS_FOR_HIGHLIGHT_TYPES.pocket
+      );
+      assert.deepEqual(
+        highlights[2].contextMenuOptions,
+        SectionsManager.CONTEXT_MENU_OPTIONS_FOR_HIGHLIGHT_TYPES.history
+      );
+    });
+    it("should throw an error if you are assigning a context menu to a non-existant highlight type", () => {
+      globals.sandbox.spy(global.console, "error");
+      SectionsManager.updateSection(
+        "highlights",
+        { rows: [{ url: "foo", type: "badtype" }] },
+        false
+      );
+      const highlights = SectionsManager.sections.get("highlights").rows;
+      assert.calledOnce(console.error);
+      assert.equal(highlights[0].contextMenuOptions, undefined);
+    });
+    it("should filter out context menu options that are in CONTEXT_MENU_PREFS", () => {
+      const services = {
+        prefs: {
+          getBoolPref: o =>
+            SectionsManager.CONTEXT_MENU_PREFS[o] !== "RemoveMe",
+          addObserver() {},
+          removeObserver() {},
+        },
+      };
+      globals.set("Services", services);
+      SectionsManager.CONTEXT_MENU_PREFS = { RemoveMe: "RemoveMe" };
+      SectionsManager.CONTEXT_MENU_OPTIONS_FOR_HIGHLIGHT_TYPES = {
+        bookmark: ["KeepMe", "RemoveMe"],
+        pocket: ["KeepMe", "RemoveMe"],
+        history: ["KeepMe", "RemoveMe"],
+      };
+      SectionsManager.updateSection("highlights", { rows: FAKE_ROWS }, false);
+      const highlights = SectionsManager.sections.get("highlights").FAKE_ROWS;
+
+      // Only keep context menu options that were not supposed to be removed based on CONTEXT_MENU_PREFS
+      assert.deepEqual(highlights[0].contextMenuOptions, ["KeepMe"]);
+      assert.deepEqual(highlights[1].contextMenuOptions, ["KeepMe"]);
+      assert.deepEqual(highlights[2].contextMenuOptions, ["KeepMe"]);
+      SectionsManager.CONTEXT_MENU_OPTIONS_FOR_HIGHLIGHT_TYPES =
+        contextMenuOptionsOrig;
+      globals.restore();
+    });
+  });
+  describe("#onceInitialized", () => {
+    it("should call the callback immediately if SectionsManager is initialised", () => {
+      SectionsManager.initialized = true;
+      const callback = sinon.spy();
+      SectionsManager.onceInitialized(callback);
+      assert.calledOnce(callback);
+    });
+    it("should bind the callback to .once(INIT) if SectionsManager is not initialised", () => {
+      SectionsManager.initialized = false;
+      sinon.spy(SectionsManager, "once");
+      const callback = () => {};
+      SectionsManager.onceInitialized(callback);
+      assert.calledOnce(SectionsManager.once);
+      assert.calledWith(SectionsManager.once, SectionsManager.INIT, callback);
+    });
+  });
+  describe("#updateSectionCard", () => {
+    it("should emit an UPDATE_SECTION_CARD event with correct arguments", () => {
+      SectionsManager.addSection(
+        FAKE_ID,
+        Object.assign({}, FAKE_OPTIONS, { rows: FAKE_ROWS })
+      );
+      const spy = sinon.spy();
+      SectionsManager.on(SectionsManager.UPDATE_SECTION_CARD, spy);
+      SectionsManager.updateSectionCard(
+        FAKE_ID,
+        FAKE_URL,
+        FAKE_CARD_OPTIONS,
+        true
+      );
+      assert.calledOnce(spy);
+      assert.calledWith(
+        spy,
+        SectionsManager.UPDATE_SECTION_CARD,
+        FAKE_ID,
+        FAKE_URL,
+        FAKE_CARD_OPTIONS,
+        true
+      );
+    });
+    it("should do nothing if the section doesn't exist", () => {
+      SectionsManager.removeSection(FAKE_ID);
+      const spy = sinon.spy();
+      SectionsManager.on(SectionsManager.UPDATE_SECTION_CARD, spy);
+      SectionsManager.updateSectionCard(
+        FAKE_ID,
+        FAKE_URL,
+        FAKE_CARD_OPTIONS,
+        true
+      );
+      assert.notCalled(spy);
+    });
+  });
+  describe("#removeSectionCard", () => {
+    it("should dispatch an SECTION_UPDATE action in which cards corresponding to the given url are removed", () => {
+      const rows = [{ url: "foo.com" }, { url: "bar.com" }];
+
+      SectionsManager.addSection(
+        FAKE_ID,
+        Object.assign({}, FAKE_OPTIONS, { rows })
+      );
+      const spy = sinon.spy();
+      SectionsManager.on(SectionsManager.UPDATE_SECTION, spy);
+      SectionsManager.removeSectionCard(FAKE_ID, "foo.com");
+
+      assert.calledOnce(spy);
+      assert.equal(spy.firstCall.args[1], FAKE_ID);
+      assert.deepEqual(spy.firstCall.args[2].rows, [{ url: "bar.com" }]);
+    });
+    it("should do nothing if the section doesn't exist", () => {
+      SectionsManager.removeSection(FAKE_ID);
+      const spy = sinon.spy();
+      SectionsManager.on(SectionsManager.UPDATE_SECTION, spy);
+      SectionsManager.removeSectionCard(FAKE_ID, "bar.com");
+      assert.notCalled(spy);
+    });
+  });
+  describe("#updateBookmarkMetadata", () => {
+    beforeEach(() => {
+      let rows = [
+        {
+          url: "bar",
+          title: "title",
+          description: "description",
+          image: "image",
+          type: "trending",
+        },
+      ];
+      SectionsManager.addSection("topstories", { rows });
+      // Simulate 2 sections.
+      rows = [
+        {
+          url: "foo",
+          title: "title",
+          description: "description",
+          image: "image",
+          type: "bookmark",
+        },
+      ];
+      SectionsManager.addSection("highlights", { rows });
+    });
+
+    it("shouldn't call PlacesUtils if URL is not in topstories", () => {
+      SectionsManager.updateBookmarkMetadata({ url: "foo" });
+
+      assert.notCalled(fakePlacesUtils.history.update);
+    });
+    it("should call PlacesUtils.history.update", () => {
+      SectionsManager.updateBookmarkMetadata({ url: "bar" });
+
+      assert.calledOnce(fakePlacesUtils.history.update);
+      assert.calledWithExactly(fakePlacesUtils.history.update, {
+        url: "bar",
+        title: "title",
+        description: "description",
+        previewImageURL: "image",
+      });
+    });
+    it("should call PlacesUtils.history.insert", () => {
+      SectionsManager.updateBookmarkMetadata({ url: "bar" });
+
+      assert.calledOnce(fakePlacesUtils.history.insert);
+      assert.calledWithExactly(fakePlacesUtils.history.insert, {
+        url: "bar",
+        title: "title",
+        visits: [{}],
+      });
+    });
+  });
+});
+
+describe("SectionsFeed", () => {
+  let feed;
+  let sandbox;
+  let storage;
+  let globals;
+
+  beforeEach(() => {
+    sandbox = sinon.createSandbox();
+    SectionsManager.sections.clear();
+    SectionsManager.initialized = false;
+    globals = new GlobalOverrider();
+    globals.set("NimbusFeatures", {
+      newtab: { getAllVariables: sandbox.stub() },
+      pocketNewtab: { getAllVariables: sandbox.stub() },
+    });
+    storage = {
+      get: sandbox.stub().resolves(),
+      set: sandbox.stub().resolves(),
+    };
+    feed = new SectionsFeed();
+    feed.store = { dispatch: sinon.spy() };
+    feed.store = {
+      dispatch: sinon.spy(),
+      getState() {
+        return this.state;
+      },
+      state: {
+        Prefs: {
+          values: {
+            sectionOrder: "topsites,topstories,highlights",
+            "feeds.topsites": true,
+          },
+        },
+        Sections: [{ initialized: false }],
+      },
+      dbStorage: { getDbTable: sandbox.stub().returns(storage) },
+    };
+  });
+  afterEach(() => {
+    feed.uninit();
+    globals.restore();
+  });
+  describe("#init", () => {
+    it("should create a SectionsFeed", () => {
+      assert.instanceOf(feed, SectionsFeed);
+    });
+    it("should bind appropriate listeners", () => {
+      sinon.spy(SectionsManager, "on");
+      feed.init();
+      assert.callCount(SectionsManager.on, 4);
+      for (const [event, listener] of [
+        [SectionsManager.ADD_SECTION, feed.onAddSection],
+        [SectionsManager.REMOVE_SECTION, feed.onRemoveSection],
+        [SectionsManager.UPDATE_SECTION, feed.onUpdateSection],
+        [SectionsManager.UPDATE_SECTION_CARD, feed.onUpdateSectionCard],
+      ]) {
+        assert.calledWith(SectionsManager.on, event, listener);
+      }
+    });
+    it("should call onAddSection for any already added sections in SectionsManager", async () => {
+      await SectionsManager.init({}, storage);
+      assert.ok(SectionsManager.sections.has("topstories"));
+      assert.ok(SectionsManager.sections.has("highlights"));
+      const topstories = SectionsManager.sections.get("topstories");
+      const highlights = SectionsManager.sections.get("highlights");
+      sinon.spy(feed, "onAddSection");
+      feed.init();
+      assert.calledTwice(feed.onAddSection);
+      assert.calledWith(
+        feed.onAddSection,
+        SectionsManager.ADD_SECTION,
+        "topstories",
+        topstories
+      );
+      assert.calledWith(
+        feed.onAddSection,
+        SectionsManager.ADD_SECTION,
+        "highlights",
+        highlights
+      );
+    });
+  });
+  describe("#uninit", () => {
+    it("should unbind all listeners", () => {
+      sinon.spy(SectionsManager, "off");
+      feed.init();
+      feed.uninit();
+      assert.callCount(SectionsManager.off, 4);
+      for (const [event, listener] of [
+        [SectionsManager.ADD_SECTION, feed.onAddSection],
+        [SectionsManager.REMOVE_SECTION, feed.onRemoveSection],
+        [SectionsManager.UPDATE_SECTION, feed.onUpdateSection],
+        [SectionsManager.UPDATE_SECTION_CARD, feed.onUpdateSectionCard],
+      ]) {
+        assert.calledWith(SectionsManager.off, event, listener);
+      }
+    });
+    it("should emit an UNINIT event and set SectionsManager.initialized to false", () => {
+      const spy = sinon.spy();
+      SectionsManager.on(SectionsManager.UNINIT, spy);
+      feed.init();
+      feed.uninit();
+      assert.calledOnce(spy);
+      assert.notOk(SectionsManager.initialized);
+    });
+  });
+  describe("#onAddSection", () => {
+    it("should broadcast a SECTION_REGISTER action with the correct data", () => {
+      feed.onAddSection(null, FAKE_ID, FAKE_OPTIONS);
+      const [action] = feed.store.dispatch.firstCall.args;
+      assert.equal(action.type, "SECTION_REGISTER");
+      assert.deepEqual(
+        action.data,
+        Object.assign({ id: FAKE_ID }, FAKE_OPTIONS)
+      );
+      assert.equal(action.meta.from, MAIN_MESSAGE_TYPE);
+      assert.equal(action.meta.to, CONTENT_MESSAGE_TYPE);
+    });
+    it("should prepend id to sectionOrder pref if not already included", () => {
+      feed.store.state.Sections = [
+        { id: "topstories", enabled: true },
+        { id: "highlights", enabled: true },
+      ];
+      feed.onAddSection(null, FAKE_ID, FAKE_OPTIONS);
+      assert.calledWith(feed.store.dispatch, {
+        data: {
+          name: "sectionOrder",
+          value: `${FAKE_ID},topsites,topstories,highlights`,
+        },
+        meta: { from: "ActivityStream:Content", to: "ActivityStream:Main" },
+        type: "SET_PREF",
+      });
+    });
+  });
+  describe("#onRemoveSection", () => {
+    it("should broadcast a SECTION_DEREGISTER action with the correct data", () => {
+      feed.onRemoveSection(null, FAKE_ID);
+      const [action] = feed.store.dispatch.firstCall.args;
+      assert.equal(action.type, "SECTION_DEREGISTER");
+      assert.deepEqual(action.data, FAKE_ID);
+      // Should be broadcast
+      assert.equal(action.meta.from, MAIN_MESSAGE_TYPE);
+      assert.equal(action.meta.to, CONTENT_MESSAGE_TYPE);
+    });
+  });
+  describe("#onUpdateSection", () => {
+    it("should do nothing if no options are provided", () => {
+      feed.onUpdateSection(null, FAKE_ID, null);
+      assert.notCalled(feed.store.dispatch);
+    });
+    it("should dispatch a SECTION_UPDATE action with the correct data", () => {
+      feed.onUpdateSection(null, FAKE_ID, { rows: FAKE_ROWS });
+      const [action] = feed.store.dispatch.firstCall.args;
+      assert.equal(action.type, "SECTION_UPDATE");
+      assert.deepEqual(action.data, { id: FAKE_ID, rows: FAKE_ROWS });
+      // Should be not broadcast by default, but should update the preloaded tab, so check meta
+      assert.equal(action.meta.from, MAIN_MESSAGE_TYPE);
+      assert.equal(action.meta.to, PRELOAD_MESSAGE_TYPE);
+    });
+    it("should broadcast the action only if shouldBroadcast is true", () => {
+      feed.onUpdateSection(null, FAKE_ID, { rows: FAKE_ROWS }, true);
+      const [action] = feed.store.dispatch.firstCall.args;
+      // Should be broadcast
+      assert.equal(action.meta.from, MAIN_MESSAGE_TYPE);
+      assert.equal(action.meta.to, CONTENT_MESSAGE_TYPE);
+    });
+  });
+  describe("#onUpdateSectionCard", () => {
+    it("should do nothing if no options are provided", () => {
+      feed.onUpdateSectionCard(null, FAKE_ID, FAKE_URL, null);
+      assert.notCalled(feed.store.dispatch);
+    });
+    it("should dispatch a SECTION_UPDATE_CARD action with the correct data", () => {
+      feed.onUpdateSectionCard(null, FAKE_ID, FAKE_URL, FAKE_CARD_OPTIONS);
+      const [action] = feed.store.dispatch.firstCall.args;
+      assert.equal(action.type, "SECTION_UPDATE_CARD");
+      assert.deepEqual(action.data, {
+        id: FAKE_ID,
+        url: FAKE_URL,
+        options: FAKE_CARD_OPTIONS,
+      });
+      // Should be not broadcast by default, but should update the preloaded tab, so check meta
+      assert.equal(action.meta.from, MAIN_MESSAGE_TYPE);
+      assert.equal(action.meta.to, PRELOAD_MESSAGE_TYPE);
+    });
+    it("should broadcast the action only if shouldBroadcast is true", () => {
+      feed.onUpdateSectionCard(
+        null,
+        FAKE_ID,
+        FAKE_URL,
+        FAKE_CARD_OPTIONS,
+        true
+      );
+      const [action] = feed.store.dispatch.firstCall.args;
+      // Should be broadcast
+      assert.equal(action.meta.from, MAIN_MESSAGE_TYPE);
+      assert.equal(action.meta.to, CONTENT_MESSAGE_TYPE);
+    });
+  });
+  describe("#onAction", () => {
+    it("should bind this.init to SectionsManager.INIT on INIT", () => {
+      sinon.spy(SectionsManager, "once");
+      feed.onAction({ type: "INIT" });
+      assert.calledOnce(SectionsManager.once);
+      assert.calledWith(SectionsManager.once, SectionsManager.INIT, feed.init);
+    });
+    it("should call SectionsManager.init on action PREFS_INITIAL_VALUES", () => {
+      sinon.spy(SectionsManager, "init");
+      feed.onAction({ type: "PREFS_INITIAL_VALUES", data: { foo: "bar" } });
+      assert.calledOnce(SectionsManager.init);
+      assert.calledWith(SectionsManager.init, { foo: "bar" });
+      assert.calledOnce(feed.store.dbStorage.getDbTable);
+      assert.calledWithExactly(feed.store.dbStorage.getDbTable, "sectionPrefs");
+    });
+    it("should call SectionsManager.addBuiltInSection on suitable PREF_CHANGED events", () => {
+      sinon.spy(SectionsManager, "addBuiltInSection");
+      feed.onAction({
+        type: "PREF_CHANGED",
+        data: { name: "feeds.section.topstories.options", value: "foo" },
+      });
+      assert.calledOnce(SectionsManager.addBuiltInSection);
+      assert.calledWith(
+        SectionsManager.addBuiltInSection,
+        "feeds.section.topstories",
+        "foo"
+      );
+    });
+    it("should fire SECTION_OPTIONS_UPDATED on suitable PREF_CHANGED events", async () => {
+      await feed.onAction({
+        type: "PREF_CHANGED",
+        data: { name: "feeds.section.topstories.options", value: "foo" },
+      });
+      assert.calledOnce(feed.store.dispatch);
+      const [action] = feed.store.dispatch.firstCall.args;
+      assert.equal(action.type, "SECTION_OPTIONS_CHANGED");
+      assert.equal(action.data, "topstories");
+    });
+    it("should call SectionsManager.disableSection on SECTION_DISABLE", () => {
+      sinon.spy(SectionsManager, "disableSection");
+      feed.onAction({ type: "SECTION_DISABLE", data: 1234 });
+      assert.calledOnce(SectionsManager.disableSection);
+      assert.calledWith(SectionsManager.disableSection, 1234);
+      SectionsManager.disableSection.restore();
+    });
+    it("should call SectionsManager.enableSection on SECTION_ENABLE", () => {
+      sinon.spy(SectionsManager, "enableSection");
+      feed.onAction({ type: "SECTION_ENABLE", data: 1234 });
+      assert.calledOnce(SectionsManager.enableSection);
+      assert.calledWith(SectionsManager.enableSection, 1234);
+      SectionsManager.enableSection.restore();
+    });
+    it("should call the feed's uninit on UNINIT", () => {
+      sinon.stub(feed, "uninit");
+
+      feed.onAction({ type: "UNINIT" });
+
+      assert.calledOnce(feed.uninit);
+    });
+    it("should emit a ACTION_DISPATCHED event and forward any action in ACTIONS_TO_PROXY if there are any sections", () => {
+      const spy = sinon.spy();
+      const allowedActions = SectionsManager.ACTIONS_TO_PROXY;
+      const disallowedActions = ["PREF_CHANGED", "OPEN_PRIVATE_WINDOW"];
+      feed.init();
+      SectionsManager.on(SectionsManager.ACTION_DISPATCHED, spy);
+      // Make sure we start with no sections - no event should be emitted
+      SectionsManager.sections.clear();
+      feed.onAction({ type: allowedActions[0] });
+      assert.notCalled(spy);
+      // Then add a section and check correct behaviour
+      SectionsManager.addSection(FAKE_ID, FAKE_OPTIONS);
+      for (const action of allowedActions.concat(disallowedActions)) {
+        feed.onAction({ type: action });
+      }
+      for (const action of allowedActions) {
+        assert.calledWith(spy, "ACTION_DISPATCHED", action);
+      }
+      for (const action of disallowedActions) {
+        assert.neverCalledWith(spy, "ACTION_DISPATCHED", action);
+      }
+    });
+    it("should call updateBookmarkMetadata on PLACES_BOOKMARK_ADDED", () => {
+      const stub = sinon.stub(SectionsManager, "updateBookmarkMetadata");
+
+      feed.onAction({ type: "PLACES_BOOKMARK_ADDED", data: {} });
+
+      assert.calledOnce(stub);
+    });
+    it("should call updateSectionPrefs on UPDATE_SECTION_PREFS", () => {
+      const stub = sinon.stub(SectionsManager, "updateSectionPrefs");
+
+      feed.onAction({ type: "UPDATE_SECTION_PREFS", data: {} });
+
+      assert.calledOnce(stub);
+    });
+    it("should call SectionManager.removeSectionCard on WEBEXT_DISMISS", () => {
+      const stub = sinon.stub(SectionsManager, "removeSectionCard");
+
+      feed.onAction(
+        ac.WebExtEvent(at.WEBEXT_DISMISS, { source: "Foo", url: "bar.com" })
+      );
+
+      assert.calledOnce(stub);
+      assert.calledWith(stub, "Foo", "bar.com");
+    });
+    it("should call the feed's moveSection on SECTION_MOVE", () => {
+      sinon.stub(feed, "moveSection");
+      const id = "topsites";
+      const direction = +1;
+      feed.onAction({ type: "SECTION_MOVE", data: { id, direction } });
+
+      assert.calledOnce(feed.moveSection);
+      assert.calledWith(feed.moveSection, id, direction);
+    });
+  });
+  describe("#moveSection", () => {
+    it("should Move Down correctly", () => {
+      feed.store.state.Sections = [
+        { id: "topstories", enabled: true },
+        { id: "highlights", enabled: true },
+      ];
+      feed.moveSection("topsites", +1);
+      assert.calledOnce(feed.store.dispatch);
+      assert.calledWith(feed.store.dispatch, {
+        data: { name: "sectionOrder", value: "topstories,topsites,highlights" },
+        meta: { from: "ActivityStream:Content", to: "ActivityStream:Main" },
+        type: "SET_PREF",
+      });
+      feed.store.dispatch.resetHistory();
+      feed.moveSection("topstories", +1);
+      assert.calledOnce(feed.store.dispatch);
+      assert.calledWith(feed.store.dispatch, {
+        data: { name: "sectionOrder", value: "topsites,highlights,topstories" },
+        meta: { from: "ActivityStream:Content", to: "ActivityStream:Main" },
+        type: "SET_PREF",
+      });
+    });
+    it("should Move Up correctly", () => {
+      feed.store.state.Sections = [
+        { id: "topstories", enabled: true },
+        { id: "highlights", enabled: true },
+      ];
+      feed.moveSection("topstories", -1);
+      assert.calledOnce(feed.store.dispatch);
+      assert.calledWith(feed.store.dispatch, {
+        data: { name: "sectionOrder", value: "topstories,topsites,highlights" },
+        meta: { from: "ActivityStream:Content", to: "ActivityStream:Main" },
+        type: "SET_PREF",
+      });
+      feed.store.dispatch.resetHistory();
+      feed.moveSection("highlights", -1);
+      assert.calledOnce(feed.store.dispatch);
+      assert.calledWith(feed.store.dispatch, {
+        data: { name: "sectionOrder", value: "topsites,highlights,topstories" },
+        meta: { from: "ActivityStream:Content", to: "ActivityStream:Main" },
+        type: "SET_PREF",
+      });
+    });
+    it("should skip over sections that aren't enabled", () => {
+      feed.store.state.Sections = [
+        { id: "topstories", enabled: false },
+        { id: "highlights", enabled: true },
+      ];
+      feed.moveSection("highlights", -1);
+      assert.calledOnce(feed.store.dispatch);
+      assert.calledWith(feed.store.dispatch, {
+        data: { name: "sectionOrder", value: "highlights,topsites,topstories" },
+        meta: { from: "ActivityStream:Content", to: "ActivityStream:Main" },
+        type: "SET_PREF",
+      });
+      feed.store.dispatch.resetHistory();
+      feed.moveSection("topsites", +1);
+      assert.calledOnce(feed.store.dispatch);
+      assert.calledWith(feed.store.dispatch, {
+        data: { name: "sectionOrder", value: "topstories,highlights,topsites" },
+        meta: { from: "ActivityStream:Content", to: "ActivityStream:Main" },
+        type: "SET_PREF",
+      });
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/ShortUrl.test.js b/browser/components/newtab/test/unit/lib/ShortUrl.test.js
new file mode 100644
index 0000000000..201e5226fd
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/ShortUrl.test.js
@@ -0,0 +1,104 @@
+import { GlobalOverrider } from "test/unit/utils";
+import { shortURL } from "lib/ShortURL.sys.mjs";
+
+const puny = "xn--kpry57d";
+const idn = "台灣";
+
+describe("shortURL", () => {
+  let globals;
+  let IDNStub;
+  let getPublicSuffixFromHostStub;
+
+  beforeEach(() => {
+    IDNStub = sinon.stub().callsFake(host => host.replace(puny, idn));
+    getPublicSuffixFromHostStub = sinon.stub().returns("com");
+
+    globals = new GlobalOverrider();
+    globals.set("IDNService", { convertToDisplayIDN: IDNStub });
+    globals.set("Services", {
+      eTLD: { getPublicSuffixFromHost: getPublicSuffixFromHostStub },
+    });
+  });
+
+  afterEach(() => {
+    globals.restore();
+  });
+
+  it("should return a blank string if url is falsey", () => {
+    assert.equal(shortURL({ url: false }), "");
+    assert.equal(shortURL({ url: "" }), "");
+    assert.equal(shortURL({}), "");
+  });
+
+  it("should return the 'url' if not a valid url", () => {
+    const checkInvalid = url => assert.equal(shortURL({ url }), url);
+    checkInvalid(true);
+    checkInvalid("something");
+    checkInvalid("http:");
+    checkInvalid("http::double");
+    checkInvalid("http://badport:65536/");
+  });
+
+  it("should remove the eTLD", () => {
+    assert.equal(shortURL({ url: "http://com.blah.com" }), "com.blah");
+  });
+
+  it("should convert host to idn when calling shortURL", () => {
+    assert.equal(shortURL({ url: `http://${puny}.blah.com` }), `${idn}.blah`);
+  });
+
+  it("should get the hostname from .url", () => {
+    assert.equal(shortURL({ url: "http://bar.com" }), "bar");
+  });
+
+  it("should not strip out www if not first subdomain", () => {
+    assert.equal(shortURL({ url: "http://foo.www.com" }), "foo.www");
+  });
+
+  it("should convert to lowercase", () => {
+    assert.equal(shortURL({ url: "HTTP://FOO.COM" }), "foo");
+  });
+
+  it("should not include the port", () => {
+    assert.equal(shortURL({ url: "http://foo.com:8888" }), "foo");
+  });
+
+  it("should return hostname for localhost", () => {
+    getPublicSuffixFromHostStub.throws("insufficient domain levels");
+
+    assert.equal(shortURL({ url: "http://localhost:8000/" }), "localhost");
+  });
+
+  it("should return hostname for ip address", () => {
+    getPublicSuffixFromHostStub.throws("host is ip address");
+
+    assert.equal(shortURL({ url: "http://127.0.0.1/foo" }), "127.0.0.1");
+  });
+
+  it("should return etld for www.gov.uk (www-only non-etld)", () => {
+    getPublicSuffixFromHostStub.returns("gov.uk");
+
+    assert.equal(
+      shortURL({ url: "https://www.gov.uk/countersigning" }),
+      "gov.uk"
+    );
+  });
+
+  it("should return idn etld for www-only non-etld", () => {
+    getPublicSuffixFromHostStub.returns(puny);
+
+    assert.equal(shortURL({ url: `https://www.${puny}/foo` }), idn);
+  });
+
+  it("should return not the protocol for file:", () => {
+    assert.equal(shortURL({ url: "file:///foo/bar.txt" }), "/foo/bar.txt");
+  });
+
+  it("should return not the protocol for about:", () => {
+    assert.equal(shortURL({ url: "about:newtab" }), "newtab");
+  });
+
+  it("should fall back to full url as a last resort", () => {
+    assert.equal(shortURL({ url: "about:" }), "about:");
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/SiteClassifier.test.js b/browser/components/newtab/test/unit/lib/SiteClassifier.test.js
new file mode 100644
index 0000000000..cd97707e9b
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/SiteClassifier.test.js
@@ -0,0 +1,252 @@
+import { classifySite } from "lib/SiteClassifier.sys.mjs";
+
+const FAKE_CLASSIFIER_DATA = [
+  {
+    type: "hostname-and-params-match",
+    criteria: [
+      {
+        hostname: "hostnameandparams.com",
+        params: [
+          {
+            key: "param1",
+            value: "val1",
+          },
+        ],
+      },
+    ],
+    weight: 300,
+  },
+  {
+    type: "url-match",
+    criteria: [{ url: "https://fullurl.com/must/match" }],
+    weight: 400,
+  },
+  {
+    type: "params-match",
+    criteria: [
+      {
+        params: [
+          {
+            key: "param1",
+            value: "val1",
+          },
+          {
+            key: "param2",
+            value: "val2",
+          },
+        ],
+      },
+    ],
+    weight: 200,
+  },
+  {
+    type: "params-prefix-match",
+    criteria: [
+      {
+        params: [
+          {
+            key: "client",
+            prefix: "fir",
+          },
+        ],
+      },
+    ],
+    weight: 200,
+  },
+  {
+    type: "has-params",
+    criteria: [
+      {
+        params: [{ key: "has-param1" }, { key: "has-param2" }],
+      },
+    ],
+    weight: 100,
+  },
+  {
+    type: "search-engine",
+    criteria: [
+      { sld: "google" },
+      { hostname: "bing.com" },
+      { hostname: "duckduckgo.com" },
+    ],
+    weight: 1,
+  },
+  {
+    type: "news-portal",
+    criteria: [
+      { hostname: "yahoo.com" },
+      { hostname: "aol.com" },
+      { hostname: "msn.com" },
+    ],
+    weight: 1,
+  },
+  {
+    type: "social-media",
+    criteria: [{ hostname: "facebook.com" }, { hostname: "twitter.com" }],
+    weight: 1,
+  },
+  {
+    type: "ecommerce",
+    criteria: [{ sld: "amazon" }, { hostname: "ebay.com" }],
+    weight: 1,
+  },
+];
+
+describe("SiteClassifier", () => {
+  function RemoteSettings() {
+    return {
+      get() {
+        return Promise.resolve(FAKE_CLASSIFIER_DATA);
+      },
+    };
+  }
+
+  it("should return the right category", async () => {
+    assert.equal(
+      "hostname-and-params-match",
+      await classifySite(
+        "https://hostnameandparams.com?param1=val1",
+        RemoteSettings
+      )
+    );
+    assert.equal(
+      "other",
+      await classifySite(
+        "https://hostnameandparams.com?param1=val",
+        RemoteSettings
+      )
+    );
+    assert.equal(
+      "other",
+      await classifySite(
+        "https://hostnameandparams.com?param=val1",
+        RemoteSettings
+      )
+    );
+    assert.equal(
+      "other",
+      await classifySite("https://hostnameandparams.com", RemoteSettings)
+    );
+    assert.equal(
+      "other",
+      await classifySite("https://params.com?param1=val1", RemoteSettings)
+    );
+
+    assert.equal(
+      "url-match",
+      await classifySite("https://fullurl.com/must/match", RemoteSettings)
+    );
+    assert.equal(
+      "other",
+      await classifySite("http://fullurl.com/must/match", RemoteSettings)
+    );
+
+    assert.equal(
+      "params-match",
+      await classifySite(
+        "https://example.com?param1=val1&param2=val2",
+        RemoteSettings
+      )
+    );
+    assert.equal(
+      "params-match",
+      await classifySite(
+        "https://example.com?param1=val1&param2=val2&other=other",
+        RemoteSettings
+      )
+    );
+    assert.equal(
+      "other",
+      await classifySite(
+        "https://example.com?param1=val2&param2=val1",
+        RemoteSettings
+      )
+    );
+    assert.equal(
+      "other",
+      await classifySite("https://example.com?param1&param2", RemoteSettings)
+    );
+
+    assert.equal(
+      "params-prefix-match",
+      await classifySite("https://search.com?client=firefox", RemoteSettings)
+    );
+    assert.equal(
+      "params-prefix-match",
+      await classifySite("https://search.com?client=fir", RemoteSettings)
+    );
+    assert.equal(
+      "other",
+      await classifySite(
+        "https://search.com?client=mozillafirefox",
+        RemoteSettings
+      )
+    );
+
+    assert.equal(
+      "has-params",
+      await classifySite(
+        "https://example.com?has-param1=val1&has-param2=val2",
+        RemoteSettings
+      )
+    );
+    assert.equal(
+      "has-params",
+      await classifySite(
+        "https://example.com?has-param1&has-param2",
+        RemoteSettings
+      )
+    );
+    assert.equal(
+      "has-params",
+      await classifySite(
+        "https://example.com?has-param1&has-param2&other=other",
+        RemoteSettings
+      )
+    );
+    assert.equal(
+      "other",
+      await classifySite("https://example.com?has-param1", RemoteSettings)
+    );
+    assert.equal(
+      "other",
+      await classifySite("https://example.com?has-param2", RemoteSettings)
+    );
+
+    assert.equal(
+      "search-engine",
+      await classifySite("https://google.com", RemoteSettings)
+    );
+    assert.equal(
+      "search-engine",
+      await classifySite("https://google.de", RemoteSettings)
+    );
+    assert.equal(
+      "search-engine",
+      await classifySite("http://bing.com/?q=firefox", RemoteSettings)
+    );
+
+    assert.equal(
+      "news-portal",
+      await classifySite("https://yahoo.com", RemoteSettings)
+    );
+
+    assert.equal(
+      "social-media",
+      await classifySite("http://twitter.com/firefox", RemoteSettings)
+    );
+
+    assert.equal(
+      "ecommerce",
+      await classifySite("https://amazon.com", RemoteSettings)
+    );
+    assert.equal(
+      "ecommerce",
+      await classifySite("https://amazon.ca", RemoteSettings)
+    );
+    assert.equal(
+      "ecommerce",
+      await classifySite("https://ebay.com", RemoteSettings)
+    );
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/SystemTickFeed.test.js b/browser/components/newtab/test/unit/lib/SystemTickFeed.test.js
new file mode 100644
index 0000000000..a0789b182e
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/SystemTickFeed.test.js
@@ -0,0 +1,79 @@
+import {
+  SYSTEM_TICK_INTERVAL,
+  SystemTickFeed,
+} from "lib/SystemTickFeed.sys.mjs";
+import { actionTypes as at } from "common/Actions.sys.mjs";
+import { GlobalOverrider } from "test/unit/utils";
+
+describe("System Tick Feed", () => {
+  let globals;
+  let instance;
+  let clock;
+
+  beforeEach(() => {
+    globals = new GlobalOverrider();
+    clock = sinon.useFakeTimers();
+
+    instance = new SystemTickFeed();
+    instance.store = {
+      getState() {
+        return {};
+      },
+      dispatch() {},
+    };
+  });
+  afterEach(() => {
+    globals.restore();
+    clock.restore();
+  });
+  it("should create a SystemTickFeed", () => {
+    assert.instanceOf(instance, SystemTickFeed);
+  });
+  it("should fire SYSTEM_TICK events at configured interval", () => {
+    globals.set("ChromeUtils", {
+      idleDispatch: f => f(),
+    });
+    let expectation = sinon
+      .mock(instance.store)
+      .expects("dispatch")
+      .twice()
+      .withExactArgs({ type: at.SYSTEM_TICK });
+
+    instance.onAction({ type: at.INIT });
+    clock.tick(SYSTEM_TICK_INTERVAL * 2);
+    expectation.verify();
+  });
+  it("should not fire SYSTEM_TICK events after UNINIT", () => {
+    let expectation = sinon.mock(instance.store).expects("dispatch").never();
+
+    instance.onAction({ type: at.UNINIT });
+    clock.tick(SYSTEM_TICK_INTERVAL * 2);
+    expectation.verify();
+  });
+  it("should not fire SYSTEM_TICK events while the user is away", () => {
+    let expectation = sinon.mock(instance.store).expects("dispatch").never();
+
+    instance.onAction({ type: at.INIT });
+    instance._idleService = { idleTime: SYSTEM_TICK_INTERVAL + 1 };
+    clock.tick(SYSTEM_TICK_INTERVAL * 3);
+    expectation.verify();
+    instance.onAction({ type: at.UNINIT });
+  });
+  it("should fire SYSTEM_TICK immediately when the user is active again", () => {
+    globals.set("ChromeUtils", {
+      idleDispatch: f => f(),
+    });
+    let expectation = sinon
+      .mock(instance.store)
+      .expects("dispatch")
+      .once()
+      .withExactArgs({ type: at.SYSTEM_TICK });
+
+    instance.onAction({ type: at.INIT });
+    instance._idleService = { idleTime: SYSTEM_TICK_INTERVAL + 1 };
+    clock.tick(SYSTEM_TICK_INTERVAL * 3);
+    instance.observe();
+    expectation.verify();
+    instance.onAction({ type: at.UNINIT });
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/TippyTopProvider.test.js b/browser/components/newtab/test/unit/lib/TippyTopProvider.test.js
new file mode 100644
index 0000000000..661a6b7b83
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/TippyTopProvider.test.js
@@ -0,0 +1,121 @@
+import { GlobalOverrider } from "test/unit/utils";
+import { TippyTopProvider } from "lib/TippyTopProvider.sys.mjs";
+
+describe("TippyTopProvider", () => {
+  let instance;
+  let globals;
+  beforeEach(async () => {
+    globals = new GlobalOverrider();
+    let fetchStub = globals.sandbox.stub();
+    globals.set("fetch", fetchStub);
+    fetchStub.resolves({
+      ok: true,
+      status: 200,
+      json: () =>
+        Promise.resolve([
+          {
+            domains: ["facebook.com"],
+            image_url: "images/facebook-com.png",
+            favicon_url: "images/facebook-com.png",
+            background_color: "#3b5998",
+          },
+          {
+            domains: ["gmail.com", "mail.google.com"],
+            image_url: "images/gmail-com.png",
+            favicon_url: "images/gmail-com.png",
+            background_color: "#000000",
+          },
+        ]),
+    });
+    instance = new TippyTopProvider();
+    await instance.init();
+  });
+  it("should provide an icon for facebook.com", () => {
+    const site = instance.processSite({ url: "https://facebook.com" });
+    assert.equal(
+      site.tippyTopIcon,
+      "chrome://activity-stream/content/data/content/tippytop/images/facebook-com.png"
+    );
+    assert.equal(
+      site.smallFavicon,
+      "chrome://activity-stream/content/data/content/tippytop/images/facebook-com.png"
+    );
+    assert.equal(site.backgroundColor, "#3b5998");
+  });
+  it("should provide an icon for www.facebook.com", () => {
+    const site = instance.processSite({ url: "https://www.facebook.com" });
+    assert.equal(
+      site.tippyTopIcon,
+      "chrome://activity-stream/content/data/content/tippytop/images/facebook-com.png"
+    );
+    assert.equal(
+      site.smallFavicon,
+      "chrome://activity-stream/content/data/content/tippytop/images/facebook-com.png"
+    );
+    assert.equal(site.backgroundColor, "#3b5998");
+  });
+  it("should not provide an icon for other.facebook.com", () => {
+    const site = instance.processSite({ url: "https://other.facebook.com" });
+    assert.isUndefined(site.tippyTopIcon);
+  });
+  it("should provide an icon for other.facebook.com with stripping", () => {
+    const site = instance.processSite(
+      { url: "https://other.facebook.com" },
+      "*"
+    );
+    assert.equal(
+      site.tippyTopIcon,
+      "chrome://activity-stream/content/data/content/tippytop/images/facebook-com.png"
+    );
+  });
+  it("should provide an icon for facebook.com/foobar", () => {
+    const site = instance.processSite({ url: "https://facebook.com/foobar" });
+    assert.equal(
+      site.tippyTopIcon,
+      "chrome://activity-stream/content/data/content/tippytop/images/facebook-com.png"
+    );
+    assert.equal(
+      site.smallFavicon,
+      "chrome://activity-stream/content/data/content/tippytop/images/facebook-com.png"
+    );
+    assert.equal(site.backgroundColor, "#3b5998");
+  });
+  it("should provide an icon for gmail.com", () => {
+    const site = instance.processSite({ url: "https://gmail.com" });
+    assert.equal(
+      site.tippyTopIcon,
+      "chrome://activity-stream/content/data/content/tippytop/images/gmail-com.png"
+    );
+    assert.equal(
+      site.smallFavicon,
+      "chrome://activity-stream/content/data/content/tippytop/images/gmail-com.png"
+    );
+    assert.equal(site.backgroundColor, "#000000");
+  });
+  it("should provide an icon for mail.google.com", () => {
+    const site = instance.processSite({ url: "https://mail.google.com" });
+    assert.equal(
+      site.tippyTopIcon,
+      "chrome://activity-stream/content/data/content/tippytop/images/gmail-com.png"
+    );
+    assert.equal(
+      site.smallFavicon,
+      "chrome://activity-stream/content/data/content/tippytop/images/gmail-com.png"
+    );
+    assert.equal(site.backgroundColor, "#000000");
+  });
+  it("should handle garbage URLs gracefully", () => {
+    const site = instance.processSite({ url: "garbagejlfkdsa" });
+    assert.isUndefined(site.tippyTopIcon);
+    assert.isUndefined(site.backgroundColor);
+  });
+  it("should handle error when fetching and parsing manifest", async () => {
+    globals = new GlobalOverrider();
+    let fetchStub = globals.sandbox.stub();
+    globals.set("fetch", fetchStub);
+    fetchStub.rejects("whaaaa");
+    instance = new TippyTopProvider();
+    await instance.init();
+    instance.processSite({ url: "https://facebook.com" });
+  });
+});
diff --git a/browser/components/newtab/test/unit/lib/UTEventReporting.test.js b/browser/components/newtab/test/unit/lib/UTEventReporting.test.js
new file mode 100644
index 0000000000..6255568438
--- /dev/null
+++ b/browser/components/newtab/test/unit/lib/UTEventReporting.test.js
@@ -0,0 +1,115 @@
+import { UTSessionPing, UTUserEventPing } from "test/schemas/pings";
+import { GlobalOverrider } from "test/unit/utils";
+import { UTEventReporting } from "lib/UTEventReporting.sys.mjs";
+
+const FAKE_EVENT_PING_PC = {
+  event: "CLICK",
+  source: "TOP_SITES",
+  addon_version: "123",
+  user_prefs: 63,
+  session_id: "abc",
+  page: "about:newtab",
+  action_position: 5,
+  locale: "en-US",
+};
+const FAKE_SESSION_PING_PC = {
+  session_duration: 1234,
+  addon_version: "123",
+  user_prefs: 63,
+  session_id: "abc",
+  page: "about:newtab",
+  locale: "en-US",
+};
+const FAKE_EVENT_PING_UT = [
+  "activity_stream",
+  "event",
+  "CLICK",
+  "TOP_SITES",
+  {
+    addon_version: "123",
+    user_prefs: "63",
+    session_id: "abc",
+    page: "about:newtab",
+    action_position: "5",
+  },
+];
+const FAKE_SESSION_PING_UT = [
+  "activity_stream",
+  "end",
+  "session",
+  "1234",
+  {
+    addon_version: "123",
+    user_prefs: "63",
+    session_id: "abc",
+    page: "about:newtab",
+  },
+];
+
+describe("UTEventReporting", () => {
+  let globals;
+  let sandbox;
+  let utEvents;
+
+  beforeEach(() => {
+    globals = new GlobalOverrider();
+    sandbox = globals.sandbox;
+    sandbox.stub(global.Services.telemetry, "setEventRecordingEnabled");
+    sandbox.stub(global.Services.telemetry, "recordEvent");
+
+    utEvents = new UTEventReporting();
+  });
+
+  afterEach(() => {
+    globals.restore();
+  });
+
+  describe("#sendUserEvent()", () => {
+    it("should queue up the correct data to send to Events Telemetry", async () => {
+      utEvents.sendUserEvent(FAKE_EVENT_PING_PC);
+      assert.calledWithExactly(
+        global.Services.telemetry.recordEvent,
+        ...FAKE_EVENT_PING_UT
+      );
+
+      let ping = global.Services.telemetry.recordEvent.firstCall.args;
+      assert.validate(ping, UTUserEventPing);
+    });
+  });
+
+  describe("#sendSessionEndEvent()", () => {
+    it("should queue up the correct data to send to Events Telemetry", async () => {
+      utEvents.sendSessionEndEvent(FAKE_SESSION_PING_PC);
+      assert.calledWithExactly(
+        global.Services.telemetry.recordEvent,
+        ...FAKE_SESSION_PING_UT
+      );
+
+      let ping = global.Services.telemetry.recordEvent.firstCall.args;
+      assert.validate(ping, UTSessionPing);
+    });
+  });
+
+  describe("#uninit()", () => {
+    it("should call setEventRecordingEnabled with a false value", () => {
+      assert.equal(
+        global.Services.telemetry.setEventRecordingEnabled.firstCall.args[0],
+        "activity_stream"
+      );
+      assert.equal(
+        global.Services.telemetry.setEventRecordingEnabled.firstCall.args[1],
+        true
+      );
+
+      utEvents.uninit();
+      assert.equal(
+        global.Services.telemetry.setEventRecordingEnabled.secondCall.args[0],
+        "activity_stream"
+      );
+      assert.equal(
+        global.Services.telemetry.setEventRecordingEnabled.secondCall.args[1],
+        false
+      );
+    });
+  });
+});
diff --git a/browser/components/newtab/test/unit/unit-entry.js b/browser/components/newtab/test/unit/unit-entry.js
new file mode 100644
index 0000000000..5b32269ca8
--- /dev/null
+++ b/browser/components/newtab/test/unit/unit-entry.js
@@ -0,0 +1,733 @@
+import {
+  EventEmitter,
+  FakePrefs,
+  FakensIPrefService,
+  GlobalOverrider,
+  FakeConsoleAPI,
+  FakeLogger,
+} from "test/unit/utils";
+import Adapter from "enzyme-adapter-react-16";
+import { chaiAssertions } from "test/schemas/pings";
+import enzyme from "enzyme";
+
+enzyme.configure({ adapter: new Adapter() });
+
+// Cause React warnings to make tests that trigger them fail
+const origConsoleError = console.error;
+console.error = function (msg, ...args) {
+  origConsoleError.apply(console, [msg, ...args]);
+
+  if (
+    /(Invalid prop|Failed prop type|Check the render method|React Intl)/.test(
+      msg
+    )
+  ) {
+    throw new Error(msg);
+  }
+};
+
+const req = require.context(".", true, /\.test\.jsx?$/);
+const files = req.keys();
+
+// This exposes sinon assertions to chai.assert
+sinon.assert.expose(assert, { prefix: "" });
+
+chai.use(chaiAssertions);
+
+const overrider = new GlobalOverrider();
+
+const RemoteSettings = name => ({
+  get: () => {
+    if (name === "attachment") {
+      return Promise.resolve([{ attachment: {} }]);
+    }
+    return Promise.resolve([]);
+  },
+  on: () => {},
+  off: () => {},
+});
+RemoteSettings.pollChanges = () => {};
+
+class JSWindowActorParent {
+  sendAsyncMessage(name, data) {
+    return { name, data };
+  }
+}
+
+class JSWindowActorChild {
+  sendAsyncMessage(name, data) {
+    return { name, data };
+  }
+
+  sendQuery(name, data) {
+    return Promise.resolve({ name, data });
+  }
+
+  get contentWindow() {
+    return {
+      Promise,
+    };
+  }
+}
+
+// Detect plain object passed to lazy getter APIs, and set its prototype to
+// global object, and return the global object for further modification.
+// Returns the object if it's not plain object.
+//
+// This is a workaround to make the existing testharness and testcase keep
+// working even after lazy getters are moved to plain `lazy` object.
+const cachedPlainObject = new Set();
+function updateGlobalOrObject(object) {
+  // Given this function modifies the prototype, and the following
+  // condition doesn't meet on the second call, cache the result.
+  if (cachedPlainObject.has(object)) {
+    return global;
+  }
+
+  if (Object.getPrototypeOf(object).constructor.name !== "Object") {
+    return object;
+  }
+
+  cachedPlainObject.add(object);
+  Object.setPrototypeOf(object, global);
+  return global;
+}
+
+const TEST_GLOBAL = {
+  JSWindowActorParent,
+  JSWindowActorChild,
+  AboutReaderParent: {
+    addMessageListener: (messageName, listener) => {},
+    removeMessageListener: (messageName, listener) => {},
+  },
+  AboutWelcomeTelemetry: class {
+    submitGleanPingForPing() {}
+  },
+  AddonManager: {
+    getActiveAddons() {
+      return Promise.resolve({ addons: [], fullData: false });
+    },
+  },
+  AppConstants: {
+    MOZILLA_OFFICIAL: true,
+    MOZ_APP_VERSION: "69.0a1",
+    isChinaRepack() {
+      return false;
+    },
+    isPlatformAndVersionAtMost() {
+      return false;
+    },
+    platform: "win",
+  },
+  ASRouterPreferences: {
+    console: new FakeConsoleAPI({
+      maxLogLevel: "off", // set this to "debug" or "all" to get more ASRouter logging in tests
+      prefix: "ASRouter",
+    }),
+  },
+  AWScreenUtils: {
+    evaluateTargetingAndRemoveScreens() {
+      return true;
+    },
+    async removeScreens() {
+      return true;
+    },
+    evaluateScreenTargeting() {
+      return true;
+    },
+  },
+  BrowserUtils: {
+    sendToDeviceEmailsSupported() {
+      return true;
+    },
+  },
+  UpdateUtils: { getUpdateChannel() {} },
+  BasePromiseWorker: class {
+    constructor() {
+      this.ExceptionHandlers = [];
+    }
+    post() {}
+  },
+  browserSearchRegion: "US",
+  BrowserWindowTracker: { getTopWindow() {} },
+  ChromeUtils: {
+    defineLazyGetter(object, name, f) {
+      updateGlobalOrObject(object)[name] = f();
+    },
+    defineModuleGetter: updateGlobalOrObject,
+    defineESModuleGetters: updateGlobalOrObject,
+    generateQI() {
+      return {};
+    },
+    import() {
+      return global;
+    },
+    importESModule() {
+      return global;
+    },
+  },
+  ClientEnvironment: {
+    get userId() {
+      return "foo123";
+    },
+  },
+  Components: {
+    Constructor(classId) {
+      switch (classId) {
+        case "@mozilla.org/referrer-info;1":
+          return function (referrerPolicy, sendReferrer, originalReferrer) {
+            this.referrerPolicy = referrerPolicy;
+            this.sendReferrer = sendReferrer;
+            this.originalReferrer = originalReferrer;
+          };
+      }
+      return function () {};
+    },
+    isSuccessCode: () => true,
+  },
+  ConsoleAPI: FakeConsoleAPI,
+  // NB: These are functions/constructors
+  // eslint-disable-next-line object-shorthand
+  ContentSearchUIController: function () {},
+  // eslint-disable-next-line object-shorthand
+  ContentSearchHandoffUIController: function () {},
+  Cc: {
+    "@mozilla.org/browser/nav-bookmarks-service;1": {
+      addObserver() {},
+      getService() {
+        return this;
+      },
+      removeObserver() {},
+      SOURCES: {},
+      TYPE_BOOKMARK: {},
+    },
+    "@mozilla.org/browser/nav-history-service;1": {
+      addObserver() {},
+      executeQuery() {},
+      getNewQuery() {},
+      getNewQueryOptions() {},
+      getService() {
+        return this;
+      },
+      insert() {},
+      markPageAsTyped() {},
+      removeObserver() {},
+    },
+    "@mozilla.org/io/string-input-stream;1": {
+      createInstance() {
+        return {};
+      },
+    },
+    "@mozilla.org/security/hash;1": {
+      createInstance() {
+        return {
+          init() {},
+          updateFromStream() {},
+          finish() {
+            return "0";
+          },
+        };
+      },
+    },
+    "@mozilla.org/updates/update-checker;1": { createInstance() {} },
+    "@mozilla.org/widget/useridleservice;1": {
+      getService() {
+        return {
+          idleTime: 0,
+          addIdleObserver() {},
+          removeIdleObserver() {},
+        };
+      },
+    },
+    "@mozilla.org/streamConverters;1": {
+      getService() {
+        return this;
+      },
+    },
+    "@mozilla.org/network/stream-loader;1": {
+      createInstance() {
+        return {};
+      },
+    },
+  },
+  Ci: {
+    nsICryptoHash: {},
+    nsIReferrerInfo: { UNSAFE_URL: 5 },
+    nsITimer: { TYPE_ONE_SHOT: 1 },
+    nsIWebProgressListener: { LOCATION_CHANGE_SAME_DOCUMENT: 1 },
+    nsIDOMWindow: Object,
+    nsITrackingDBService: {
+      TRACKERS_ID: 1,
+      TRACKING_COOKIES_ID: 2,
+      CRYPTOMINERS_ID: 3,
+      FINGERPRINTERS_ID: 4,
+      SOCIAL_ID: 5,
+    },
+    nsICookieBannerService: {
+      MODE_DISABLED: 0,
+      MODE_REJECT: 1,
+      MODE_REJECT_OR_ACCEPT: 2,
+      MODE_UNSET: 3,
+    },
+  },
+  Cu: {
+    importGlobalProperties() {},
+    now: () => window.performance.now(),
+    cloneInto: o => JSON.parse(JSON.stringify(o)),
+  },
+  console: {
+    ...console,
+    error() {},
+  },
+  dump() {},
+  EveryWindow: {
+    registerCallback: (id, init, uninit) => {},
+    unregisterCallback: id => {},
+  },
+  setTimeout: window.setTimeout.bind(window),
+  clearTimeout: window.clearTimeout.bind(window),
+  fetch() {},
+  // eslint-disable-next-line object-shorthand
+  Image: function () {}, // NB: This is a function/constructor
+  IOUtils: {
+    writeJSON() {
+      return Promise.resolve(0);
+    },
+    readJSON() {
+      return Promise.resolve({});
+    },
+    read() {
+      return Promise.resolve(new Uint8Array());
+    },
+    makeDirectory() {
+      return Promise.resolve(0);
+    },
+    write() {
+      return Promise.resolve(0);
+    },
+    exists() {
+      return Promise.resolve(0);
+    },
+    remove() {
+      return Promise.resolve(0);
+    },
+    stat() {
+      return Promise.resolve(0);
+    },
+  },
+  NewTabUtils: {
+    activityStreamProvider: {
+      getTopFrecentSites: () => [],
+      executePlacesQuery: async (sql, options) => ({ sql, options }),
+    },
+  },
+  OS: {
+    File: {
+      writeAtomic() {},
+      makeDir() {},
+      stat() {},
+      Error: {},
+      read() {},
+      exists() {},
+      remove() {},
+      removeEmptyDir() {},
+    },
+    Path: {
+      join() {
+        return "/";
+      },
+    },
+    Constants: {
+      Path: {
+        localProfileDir: "/",
+      },
+    },
+  },
+  PathUtils: {
+    join(...parts) {
+      return parts[parts.length - 1];
+    },
+    joinRelative(...parts) {
+      return parts[parts.length - 1];
+    },
+    getProfileDir() {
+      return Promise.resolve("/");
+    },
+    getLocalProfileDir() {
+      return Promise.resolve("/");
+    },
+  },
+  PlacesUtils: {
+    get bookmarks() {
+      return TEST_GLOBAL.Cc["@mozilla.org/browser/nav-bookmarks-service;1"];
+    },
+    get history() {
+      return TEST_GLOBAL.Cc["@mozilla.org/browser/nav-history-service;1"];
+    },
+    observers: {
+      addListener() {},
+      removeListener() {},
+    },
+  },
+  Preferences: FakePrefs,
+  PrivateBrowsingUtils: {
+    isBrowserPrivate: () => false,
+    isWindowPrivate: () => false,
+    permanentPrivateBrowsing: false,
+  },
+  DownloadsViewUI: {
+    getDisplayName: () => "filename.ext",
+    getSizeWithUnits: () => "1.5 MB",
+  },
+  FileUtils: {
+    // eslint-disable-next-line object-shorthand
+    File: function () {}, // NB: This is a function/constructor
+  },
+  Region: {
+    home: "US",
+    REGION_TOPIC: "browser-region-updated",
+  },
+  Services: {
+    dirsvc: {
+      get: () => ({ parent: { parent: { path: "appPath" } } }),
+    },
+    env: {
+      set: () => undefined,
+    },
+    locale: {
+      get appLocaleAsBCP47() {
+        return "en-US";
+      },
+      negotiateLanguages() {},
+    },
+    urlFormatter: { formatURL: str => str, formatURLPref: str => str },
+    mm: {
+      addMessageListener: (msg, cb) => this.receiveMessage(),
+      removeMessageListener() {},
+    },
+    obs: {
+      addObserver() {},
+      removeObserver() {},
+      notifyObservers() {},
+    },
+    telemetry: {
+      setEventRecordingEnabled: () => {},
+      recordEvent: eventDetails => {},
+      scalarSet: () => {},
+      keyedScalarAdd: () => {},
+    },
+    uuid: {
+      generateUUID() {
+        return "{foo-123-foo}";
+      },
+    },
+    console: { logStringMessage: () => {} },
+    prefs: new FakensIPrefService(),
+    tm: {
+      dispatchToMainThread: cb => cb(),
+      idleDispatchToMainThread: cb => cb(),
+    },
+    eTLD: {
+      getBaseDomain({ spec }) {
+        return spec.match(/\/([^/]+)/)[1];
+      },
+      getBaseDomainFromHost(host) {
+        return host.match(/.*?(\w+\.\w+)$/)[1];
+      },
+      getPublicSuffix() {},
+    },
+    io: {
+      newURI: spec => ({
+        mutate: () => ({
+          setRef: ref => ({
+            finalize: () => ({
+              ref,
+              spec,
+            }),
+          }),
+        }),
+        spec,
+      }),
+    },
+    search: {
+      init() {
+        return Promise.resolve();
+      },
+      getVisibleEngines: () =>
+        Promise.resolve([{ identifier: "google" }, { identifier: "bing" }]),
+      defaultEngine: {
+        identifier: "google",
+        searchForm:
+          "https://www.google.com/search?q=&ie=utf-8&oe=utf-8&client=firefox-b",
+        aliases: ["@google"],
+      },
+      defaultPrivateEngine: {
+        identifier: "bing",
+        searchForm: "https://www.bing.com",
+        aliases: ["@bing"],
+      },
+      getEngineByAlias: async () => null,
+    },
+    scriptSecurityManager: {
+      createNullPrincipal() {},
+      getSystemPrincipal() {},
+    },
+    wm: {
+      getMostRecentWindow: () => window,
+      getMostRecentBrowserWindow: () => window,
+      getEnumerator: () => [],
+    },
+    ww: { registerNotification() {}, unregisterNotification() {} },
+    appinfo: { appBuildID: "20180710100040", version: "69.0a1" },
+    scriptloader: { loadSubScript: () => {} },
+    startup: {
+      getStartupInfo() {
+        return {
+          process: {
+            getTime() {
+              return 1588010448000;
+            },
+          },
+        };
+      },
+    },
+  },
+  XPCOMUtils: {
+    defineLazyGlobalGetters: updateGlobalOrObject,
+    defineLazyModuleGetters: updateGlobalOrObject,
+    defineLazyServiceGetter: updateGlobalOrObject,
+    defineLazyServiceGetters: updateGlobalOrObject,
+    defineLazyPreferenceGetter(object, name) {
+      updateGlobalOrObject(object)[name] = "";
+    },
+    generateQI() {
+      return {};
+    },
+  },
+  EventEmitter,
+  ShellService: {
+    doesAppNeedPin: () => false,
+    isDefaultBrowser: () => true,
+  },
+  FilterExpressions: {
+    eval() {
+      return Promise.resolve(false);
+    },
+  },
+  RemoteSettings,
+  Localization: class {
+    async formatMessages(stringsIds) {
+      return Promise.resolve(
+        stringsIds.map(({ id, args }) => ({ value: { string_id: id, args } }))
+      );
+    }
+    async formatValue(stringId) {
+      return Promise.resolve(stringId);
+    }
+  },
+  FxAccountsConfig: {
+    promiseConnectAccountURI(id) {
+      return Promise.resolve(id);
+    },
+  },
+  FX_MONITOR_OAUTH_CLIENT_ID: "fake_client_id",
+  ExperimentAPI: {
+    getExperiment() {},
+    getExperimentMetaData() {},
+    getRolloutMetaData() {},
+  },
+  NimbusFeatures: {
+    glean: {
+      getVariable() {},
+    },
+    newtab: {
+      getVariable() {},
+      getAllVariables() {},
+      onUpdate() {},
+      offUpdate() {},
+    },
+    pocketNewtab: {
+      getVariable() {},
+      getAllVariables() {},
+      onUpdate() {},
+      offUpdate() {},
+    },
+    cookieBannerHandling: {
+      getVariable() {},
+    },
+  },
+  TelemetryEnvironment: {
+    setExperimentActive() {},
+    currentEnvironment: {
+      profile: {
+        creationDate: 16587,
+      },
+      settings: {},
+    },
+  },
+  TelemetryStopwatch: {
+    start: () => {},
+    finish: () => {},
+  },
+  Sampling: {
+    ratioSample(seed, ratios) {
+      return Promise.resolve(0);
+    },
+  },
+  BrowserHandler: {
+    get kiosk() {
+      return false;
+    },
+  },
+  TelemetrySession: {
+    getMetadata(reason) {
+      return {
+        reason,
+        sessionId: "fake_session_id",
+      };
+    },
+  },
+  PageThumbs: {
+    addExpirationFilter() {},
+    removeExpirationFilter() {},
+  },
+  Logger: FakeLogger,
+  getFxAccountsSingleton() {},
+  AboutNewTab: {},
+  Glean: {
+    newtab: {
+      opened: {
+        record() {},
+      },
+      closed: {
+        record() {},
+      },
+      locale: {
+        set() {},
+      },
+      newtabCategory: {
+        set() {},
+      },
+      homepageCategory: {
+        set() {},
+      },
+      blockedSponsors: {
+        set() {},
+      },
+      sovAllocation: {
+        set() {},
+      },
+    },
+    newtabSearch: {
+      enabled: {
+        set() {},
+      },
+    },
+    newtabHandoffPreference: {
+      enabled: {
+        set() {},
+      },
+    },
+    pocket: {
+      enabled: {
+        set() {},
+      },
+      impression: {
+        record() {},
+      },
+      isSignedIn: {
+        set() {},
+      },
+      sponsoredStoriesEnabled: {
+        set() {},
+      },
+      click: {
+        record() {},
+      },
+      save: {
+        record() {},
+      },
+      topicClick: {
+        record() {},
+      },
+      shim: {
+        set() {},
+      },
+    },
+    topsites: {
+      enabled: {
+        set() {},
+      },
+      sponsoredEnabled: {
+        set() {},
+      },
+      impression: {
+        record() {},
+      },
+      click: {
+        record() {},
+      },
+      rows: {
+        set() {},
+      },
+      showPrivacyClick: {
+        record() {},
+      },
+      dismiss: {
+        record() {},
+      },
+      prefChanged: {
+        record() {},
+      },
+      sponsoredTilesConfigured: {
+        set() {},
+      },
+      sponsoredTilesReceived: {
+        set() {},
+      },
+    },
+    topSites: {
+      pingType: {
+        set() {},
+      },
+      position: {
+        set() {},
+      },
+      source: {
+        set() {},
+      },
+      tileId: {
+        set() {},
+      },
+      reportingUrl: {
+        set() {},
+      },
+      advertiser: {
+        set() {},
+      },
+      contextId: {
+        set() {},
+      },
+    },
+  },
+  GleanPings: {
+    newtab: {
+      submit() {},
+    },
+    topSites: {
+      submit() {},
+    },
+    spoc: {
+      submit() {},
+    },
+  },
+  Utils: {
+    SERVER_URL: "bogus://foo",
+  },
+};
+overrider.set(TEST_GLOBAL);
+
+describe("activity-stream", () => {
+  after(() => overrider.restore());
+  files.forEach(file => req(file));
+});
diff --git a/browser/components/newtab/test/unit/utils.js b/browser/components/newtab/test/unit/utils.js
new file mode 100644
index 0000000000..22069b8635
--- /dev/null
+++ b/browser/components/newtab/test/unit/utils.js
@@ -0,0 +1,406 @@
+/**
+ * GlobalOverrider - Utility that allows you to override properties on the global object.
+ *                   See unit-entry.js for example usage.
+ */
+export class GlobalOverrider {
+  constructor() {
+    this.originalGlobals = new Map();
+    this.sandbox = sinon.createSandbox();
+  }
+
+  /**
+   * _override - Internal method to override properties on the global object.
+   *             The first time a given key is overridden, we cache the original
+   *             value in this.originalGlobals so that later it can be restored.
+   *
+   * @param  {string} key The identifier of the property
+   * @param  {any} value The value to which the property should be reassigned
+   */
+  _override(key, value) {
+    if (!this.originalGlobals.has(key)) {
+      this.originalGlobals.set(key, global[key]);
+    }
+    global[key] = value;
+  }
+
+  /**
+   * set - Override a given property, or all properties on an object
+   *
+   * @param  {string|object} key If a string, the identifier of the property
+   *                             If an object, a number of properties and values to which they should be reassigned.
+   * @param  {any} value The value to which the property should be reassigned
+   * @return {type}       description
+   */
+  set(key, value) {
+    if (!value && typeof key === "object") {
+      const overrides = key;
+      Object.keys(overrides).forEach(k => this._override(k, overrides[k]));
+    } else {
+      this._override(key, value);
+    }
+    return value;
+  }
+
+  /**
+   * reset - Reset the global sandbox, so all state on spies, stubs etc. is cleared.
+   *         You probably want to call this after each test.
+   */
+  reset() {
+    this.sandbox.reset();
+  }
+
+  /**
+   * restore - Restore the global sandbox and reset all overriden properties to
+   *           their original values. You should call this after all tests have completed.
+   */
+  restore() {
+    this.sandbox.restore();
+    this.originalGlobals.forEach((value, key) => {
+      global[key] = value;
+    });
+  }
+}
+
+/**
+ * A map of mocked preference names and values, used by `FakensIPrefBranch`,
+ * `FakensIPrefService`, and `FakePrefs`.
+ *
+ * Tests should add entries to this map for any preferences they'd like to set,
+ * and remove any entries during teardown for preferences that shouldn't be
+ * shared between tests.
+ */
+export const FAKE_GLOBAL_PREFS = new Map();
+
+/**
+ * Very simple fake for the most basic semantics of nsIPrefBranch. Lots of
+ * things aren't yet supported.  Feel free to add them in.
+ *
+ * @param {Object} args - optional arguments
+ * @param {Function} args.initHook - if present, will be called back
+ *                   inside the constructor. Typically used from tests
+ *                   to save off a pointer to the created instance so that
+ *                   stubs and spies can be inspected by the test code.
+ */
+export class FakensIPrefBranch {
+  PREF_INVALID = "invalid";
+  PREF_INT = "integer";
+  PREF_BOOL = "boolean";
+  PREF_STRING = "string";
+
+  constructor(args) {
+    if (args) {
+      if ("initHook" in args) {
+        args.initHook.call(this);
+      }
+      if (args.defaultBranch) {
+        this.prefs = new Map();
+      } else {
+        this.prefs = FAKE_GLOBAL_PREFS;
+      }
+    } else {
+      this.prefs = FAKE_GLOBAL_PREFS;
+    }
+    this._prefBranch = {};
+    this.observers = new Map();
+  }
+  addObserver(prefix, callback) {
+    this.observers.set(prefix, callback);
+  }
+  removeObserver(prefix, callback) {
+    this.observers.delete(prefix, callback);
+  }
+  setStringPref(prefName, value) {
+    this.set(prefName, value);
+  }
+  getStringPref(prefName, defaultValue) {
+    return this.get(prefName, defaultValue);
+  }
+  setBoolPref(prefName, value) {
+    this.set(prefName, value);
+  }
+  getBoolPref(prefName) {
+    return this.get(prefName);
+  }
+  setIntPref(prefName, value) {
+    this.set(prefName, value);
+  }
+  getIntPref(prefName) {
+    return this.get(prefName);
+  }
+  setCharPref(prefName, value) {
+    this.set(prefName, value);
+  }
+  getCharPref(prefName) {
+    return this.get(prefName);
+  }
+  clearUserPref(prefName) {
+    this.prefs.delete(prefName);
+  }
+  get(prefName, defaultValue) {
+    let value = this.prefs.get(prefName);
+    return typeof value === "undefined" ? defaultValue : value;
+  }
+  getPrefType(prefName) {
+    let value = this.prefs.get(prefName);
+    switch (typeof value) {
+      case "number":
+        return this.PREF_INT;
+
+      case "boolean":
+        return this.PREF_BOOL;
+
+      case "string":
+        return this.PREF_STRING;
+
+      default:
+        return this.PREF_INVALID;
+    }
+  }
+  set(prefName, value) {
+    this.prefs.set(prefName, value);
+
+    // Trigger all observers for prefixes of the changed pref name. This matches
+    // the semantics of `nsIPrefBranch`.
+    let observerPrefixes = [...this.observers.keys()].filter(prefix =>
+      prefName.startsWith(prefix)
+    );
+    for (let observerPrefix of observerPrefixes) {
+      this.observers.get(observerPrefix)("", "", prefName);
+    }
+  }
+  getChildList(prefix) {
+    return [...this.prefs.keys()].filter(prefName =>
+      prefName.startsWith(prefix)
+    );
+  }
+  prefHasUserValue(prefName) {
+    return this.prefs.has(prefName);
+  }
+  prefIsLocked(prefName) {
+    return false;
+  }
+}
+
+/**
+ * A fake `Services.prefs` implementation that extends `FakensIPrefBranch`
+ * with methods specific to `nsIPrefService`.
+ */
+export class FakensIPrefService extends FakensIPrefBranch {
+  getBranch() {}
+  getDefaultBranch(prefix) {
+    return {
+      setBoolPref() {},
+      setIntPref() {},
+      setStringPref() {},
+      clearUserPref() {},
+    };
+  }
+}
+
+/**
+ * Very simple fake for the most basic semantics of Preferences.sys.mjs.
+ * Extends FakensIPrefBranch.
+ */
+export class FakePrefs extends FakensIPrefBranch {
+  observe(prefName, callback) {
+    super.addObserver(prefName, callback);
+  }
+  ignore(prefName, callback) {
+    super.removeObserver(prefName, callback);
+  }
+  observeBranch(listener) {}
+  ignoreBranch(listener) {}
+  set(prefName, value) {
+    this.prefs.set(prefName, value);
+
+    // Trigger observers for just the changed pref name, not any of its
+    // prefixes. This matches the semantics of `Preferences.sys.mjs`.
+    if (this.observers.has(prefName)) {
+      this.observers.get(prefName)(value);
+    }
+  }
+}
+
+/**
+ * Slimmed down version of toolkit/modules/EventEmitter.sys.mjs
+ */
+export function EventEmitter() {}
+EventEmitter.decorate = function (objectToDecorate) {
+  let emitter = new EventEmitter();
+  objectToDecorate.on = emitter.on.bind(emitter);
+  objectToDecorate.off = emitter.off.bind(emitter);
+  objectToDecorate.once = emitter.once.bind(emitter);
+  objectToDecorate.emit = emitter.emit.bind(emitter);
+};
+EventEmitter.prototype = {
+  on(event, listener) {
+    if (!this._eventEmitterListeners) {
+      this._eventEmitterListeners = new Map();
+    }
+    if (!this._eventEmitterListeners.has(event)) {
+      this._eventEmitterListeners.set(event, []);
+    }
+    this._eventEmitterListeners.get(event).push(listener);
+  },
+  off(event, listener) {
+    if (!this._eventEmitterListeners) {
+      return;
+    }
+    let listeners = this._eventEmitterListeners.get(event);
+    if (listeners) {
+      this._eventEmitterListeners.set(
+        event,
+        listeners.filter(
+          l => l !== listener && l._originalListener !== listener
+        )
+      );
+    }
+  },
+  once(event, listener) {
+    return new Promise(resolve => {
+      let handler = (_, first, ...rest) => {
+        this.off(event, handler);
+        if (listener) {
+          listener(event, first, ...rest);
+        }
+        resolve(first);
+      };
+
+      handler._originalListener = listener;
+      this.on(event, handler);
+    });
+  },
+  // All arguments to this method will be sent to listeners
+  emit(event, ...args) {
+    if (
+      !this._eventEmitterListeners ||
+      !this._eventEmitterListeners.has(event)
+    ) {
+      return;
+    }
+    let originalListeners = this._eventEmitterListeners.get(event);
+    for (let listener of this._eventEmitterListeners.get(event)) {
+      // If the object was destroyed during event emission, stop
+      // emitting.
+      if (!this._eventEmitterListeners) {
+        break;
+      }
+      // If listeners were removed during emission, make sure the
+      // event handler we're going to fire wasn't removed.
+      if (
+        originalListeners === this._eventEmitterListeners.get(event) ||
+        this._eventEmitterListeners.get(event).some(l => l === listener)
+      ) {
+        try {
+          listener(event, ...args);
+        } catch (ex) {
+          // error with a listener
+        }
+      }
+    }
+  },
+};
+
+export function FakePerformance() {}
+FakePerformance.prototype = {
+  marks: new Map(),
+  now() {
+    return window.performance.now();
+  },
+  timing: { navigationStart: 222222.123 },
+  get timeOrigin() {
+    return 10000.234;
+  },
+  // XXX assumes type == "mark"
+  getEntriesByName(name, type) {
+    if (this.marks.has(name)) {
+      return this.marks.get(name);
+    }
+    return [];
+  },
+  callsToMark: 0,
+
+  /**
+   * @note The "startTime" for each mark is simply the number of times mark
+   * has been called in this object.
+   */
+  mark(name) {
+    let markObj = {
+      name,
+      entryType: "mark",
+      startTime: ++this.callsToMark,
+      duration: 0,
+    };
+
+    if (this.marks.has(name)) {
+      this.marks.get(name).push(markObj);
+      return;
+    }
+
+    this.marks.set(name, [markObj]);
+  },
+};
+
+/**
+ * addNumberReducer - a simple dummy reducer for testing that adds a number
+ */
+export function addNumberReducer(prevState = 0, action) {
+  return action.type === "ADD" ? prevState + action.data : prevState;
+}
+
+export class FakeConsoleAPI {
+  static LOG_LEVELS = {
+    all: Number.MIN_VALUE,
+    debug: 2,
+    log: 3,
+    info: 3,
+    clear: 3,
+    trace: 3,
+    timeEnd: 3,
+    time: 3,
+    assert: 3,
+    group: 3,
+    groupEnd: 3,
+    profile: 3,
+    profileEnd: 3,
+    dir: 3,
+    dirxml: 3,
+    warn: 4,
+    error: 5,
+    off: Number.MAX_VALUE,
+  };
+
+  constructor({ prefix = "", maxLogLevel = "all" } = {}) {
+    this.prefix = prefix;
+    this.prefixStr = prefix ? `${prefix}: ` : "";
+    this.maxLogLevel = maxLogLevel;
+
+    for (const level of Object.keys(FakeConsoleAPI.LOG_LEVELS)) {
+      // eslint-disable-next-line no-console
+      if (typeof console[level] === "function") {
+        this[level] = this.shouldLog(level)
+          ? this._log.bind(this, level)
+          : () => {};
+      }
+    }
+  }
+  shouldLog(level) {
+    return (
+      FakeConsoleAPI.LOG_LEVELS[this.maxLogLevel] <=
+      FakeConsoleAPI.LOG_LEVELS[level]
+    );
+  }
+  _log(level, ...args) {
+    console[level](this.prefixStr, ...args); // eslint-disable-line no-console
+  }
+}
+
+export class FakeLogger extends FakeConsoleAPI {
+  constructor() {
+    super({
+      // Don't use a prefix because the first instance gets cached and reused by
+      // other consumers that would otherwise pass their own identifying prefix.
+      maxLogLevel: "off", // Change this to "debug" or "all" to get more logging in tests
+    });
+  }
+}