1 files changed, 86 insertions, 0 deletions
diff --git a/devtools/client/memory/test/browser/browser_memory_diff_01.js b/devtools/client/memory/test/browser/browser_memory_diff_01.js
new file mode 100644
index 0000000000..7b6487565f
--- /dev/null
+++ b/devtools/client/memory/test/browser/browser_memory_diff_01.js
@@ -0,0 +1,86 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Test diffing.
+
+"use strict";
+
+const {
+  diffingState,
+  treeMapState,
+} = require("resource://devtools/client/memory/constants.js");
+
+const TEST_URL =
+  "http://example.com/browser/devtools/client/memory/test/browser/doc_steady_allocation.html";
+
+this.test = makeMemoryTest(TEST_URL, async function ({ tab, panel }) {
+  const store = panel.panelWin.gStore;
+  const { getState } = store;
+  const doc = panel.panelWin.document;
+
+  ok(!getState().diffing, "Not diffing by default.");
+
+  // Take two snapshots.
+  const takeSnapshotButton = doc.getElementById("take-snapshot");
+  EventUtils.synthesizeMouseAtCenter(takeSnapshotButton, {}, panel.panelWin);
+  await waitForTime(1000);
+  EventUtils.synthesizeMouseAtCenter(takeSnapshotButton, {}, panel.panelWin);
+
+  // Enable diffing mode.
+  const diffButton = doc.getElementById("diff-snapshots");
+  EventUtils.synthesizeMouseAtCenter(diffButton, {}, panel.panelWin);
+  await waitUntilState(
+    store,
+    state => !!state.diffing && state.diffing.state === diffingState.SELECTING
+  );
+  ok(true, "Clicking the diffing button put us into the diffing state.");
+  is(getDisplayedSnapshotStatus(doc), "Select the baseline snapshot");
+
+  await waitUntilState(
+    store,
+    state =>
+      state.snapshots.length === 2 &&
+      state.snapshots[0].treeMap &&
+      state.snapshots[1].treeMap &&
+      state.snapshots[0].treeMap.state === treeMapState.SAVED &&
+      state.snapshots[1].treeMap.state === treeMapState.SAVED
+  );
+
+  const listItems = [...doc.querySelectorAll(".snapshot-list-item")];
+  is(listItems.length, 2, "Should have two snapshot list items");
+
+  // Select the first snapshot.
+  EventUtils.synthesizeMouseAtCenter(listItems[0], {}, panel.panelWin);
+  await waitUntilState(
+    store,
+    state =>
+      state.diffing.state === diffingState.SELECTING &&
+      state.diffing.firstSnapshotId
+  );
+  is(
+    getDisplayedSnapshotStatus(doc),
+    "Select the snapshot to compare to the baseline"
+  );
+
+  // Select the second snapshot.
+  EventUtils.synthesizeMouseAtCenter(listItems[1], {}, panel.panelWin);
+  await waitUntilState(
+    store,
+    state => state.diffing.state === diffingState.TAKING_DIFF
+  );
+  ok(true, "Selecting two snapshots for diffing triggers computing the diff");
+
+  // .startsWith because the ellipsis is lost in translation.
+  ok(getDisplayedSnapshotStatus(doc).startsWith("Computing difference"));
+
+  await waitUntilState(
+    store,
+    state => state.diffing.state === diffingState.TOOK_DIFF
+  );
+  ok(true, "And that diff is computed successfully");
+  is(getDisplayedSnapshotStatus(doc), null, "No status text anymore");
+  ok(
+    doc.querySelector(".heap-tree-item"),
+    "And instead we should be showing the tree"
+  );
+});