Adding upstream version 124.0.1.upstream/124.0.1

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

25 files changed, 1604 insertions, 0 deletions

diff --git a/devtools/client/debugger/src/utils/tests/DevToolsUtils.spec.js b/devtools/client/debugger/src/utils/tests/DevToolsUtils.spec.js
new file mode 100644
index 0000000000..be405d8628
--- /dev/null
+++ b/devtools/client/debugger/src/utils/tests/DevToolsUtils.spec.js
@@ -0,0 +1,41 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+import { reportException, executeSoon } from "../DevToolsUtils.js";
+
+describe("DevToolsUtils", () => {
+  describe("reportException", () => {
+    beforeEach(() => {
+      global.console = { error: jest.fn() };
+    });
+
+    it("calls console.error", () => {
+      reportException("caller", ["you broke it"]);
+      expect(console.error).toHaveBeenCalled();
+    });
+
+    it("returns a description of caller and exception text", () => {
+      const who = "who",
+        exception = "this is an error",
+        msgTxt = " threw an exception: ";
+
+      reportException(who, [exception]);
+
+      expect(console.error).toHaveBeenCalledWith(`${who}${msgTxt}`, [
+        exception,
+      ]);
+    });
+  });
+
+  describe("executeSoon", () => {
+    it("calls setTimeout with 0 ms", () => {
+      global.setTimeout = jest.fn();
+      const fnc = () => {};
+
+      executeSoon(fnc);
+
+      expect(setTimeout).toHaveBeenCalledWith(fnc, 0);
+    });
+  });
+});
diff --git a/devtools/client/debugger/src/utils/tests/__snapshots__/expressions.spec.js.snap b/devtools/client/debugger/src/utils/tests/__snapshots__/expressions.spec.js.snap
new file mode 100644
index 0000000000..a0d6b17bf6
--- /dev/null
+++ b/devtools/client/debugger/src/utils/tests/__snapshots__/expressions.spec.js.snap
@@ -0,0 +1,25 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`expressions wrap expression should wrap an expression 1`] = `
+"try {
+ foo
+} catch (e) {
+ e
+}"
+`;
+
+exports[`expressions wrap expression should wrap expression with a comment 1`] = `
+"try {
+ foo // yo yo
+} catch (e) {
+ e
+}"
+`;
+
+exports[`expressions wrap expression should wrap quotes 1`] = `
+"try {
+ \\"2\\"
+} catch (e) {
+ e
+}"
+`;
diff --git a/devtools/client/debugger/src/utils/tests/__snapshots__/function.spec.js.snap b/devtools/client/debugger/src/utils/tests/__snapshots__/function.spec.js.snap
new file mode 100644
index 0000000000..8d83a48d3b
--- /dev/null
+++ b/devtools/client/debugger/src/utils/tests/__snapshots__/function.spec.js.snap
@@ -0,0 +1,25 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`function findFunctionText finds class function 1`] = `
+"bar() {
+ 2 + 2;
+}"
+`;
+
+exports[`function findFunctionText finds function 1`] = `
+"async function exSlowFoo() {
+ return \\"yay in a bit\\";
+}"
+`;
+
+exports[`function findFunctionText finds function signature 1`] = `
+"async function exSlowFoo() {
+ return \\"yay in a bit\\";
+}"
+`;
+
+exports[`function findFunctionText finds property function 1`] = `
+"function name() {
+ 2 + 2;
+}"
+`;
diff --git a/devtools/client/debugger/src/utils/tests/__snapshots__/indentation.spec.js.snap b/devtools/client/debugger/src/utils/tests/__snapshots__/indentation.spec.js.snap
new file mode 100644
index 0000000000..883d48a7ff
--- /dev/null
+++ b/devtools/client/debugger/src/utils/tests/__snapshots__/indentation.spec.js.snap
@@ -0,0 +1,27 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`indentation mad indentation 1`] = `
+"try {
+console.log(\\"yo\\")
+} catch (e) {
+console.log(\\"yo\\")
+ }"
+`;
+
+exports[`indentation one function 1`] = `
+"function foo() {
+ console.log(\\"yo\\")
+}"
+`;
+
+exports[`indentation one line 1`] = `"foo"`;
+
+exports[`indentation simple 1`] = `"foo"`;
+
+exports[`indentation try catch 1`] = `
+"try {
+ console.log(\\"yo\\")
+} catch (e) {
+ console.log(\\"yo\\")
+}"
+`;
diff --git a/devtools/client/debugger/src/utils/tests/assert.spec.js b/devtools/client/debugger/src/utils/tests/assert.spec.js
new file mode 100644
index 0000000000..031665c5d3
--- /dev/null
+++ b/devtools/client/debugger/src/utils/tests/assert.spec.js
@@ -0,0 +1,30 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+import assert from "../assert.js";
+
+let testAssertMessageHead, testAssertMessage;
+
+describe("assert", () => {
+  beforeEach(() => {
+    testAssertMessageHead = "Assertion failure: ";
+    testAssertMessage = "Test assert.js Message";
+  });
+
+  describe("when condition is truthy", () => {
+    it("does not throw an Error", () => {
+      expect(() => {
+        assert(true, testAssertMessage);
+      }).not.toThrow();
+    });
+  });
+
+  describe("when condition is falsy", () => {
+    it("throws an Error displaying the passed message", () => {
+      expect(() => {
+        assert(false, testAssertMessage);
+      }).toThrow(new Error(testAssertMessageHead + testAssertMessage));
+    });
+  });
+});
diff --git a/devtools/client/debugger/src/utils/tests/build-query.spec.js b/devtools/client/debugger/src/utils/tests/build-query.spec.js
new file mode 100644
index 0000000000..dbd0eba4a4
--- /dev/null
+++ b/devtools/client/debugger/src/utils/tests/build-query.spec.js
@@ -0,0 +1,256 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+import buildQuery from "../build-query";
+
+describe("build-query", () => {
+  it("case-sensitive, whole-word, regex search", () => {
+    const query = buildQuery(
+      "hi.*",
+      {
+        caseSensitive: true,
+        wholeWord: true,
+        regexMatch: true,
+      },
+      {}
+    );
+
+    expect(query.source).toBe("\\bhi.*\\b");
+    expect(query.flags).toBe("");
+    expect(query.ignoreCase).toBe(false);
+  });
+
+  it("case-sensitive, whole-word, regex search, global", () => {
+    const query = buildQuery(
+      "hi.*",
+      {
+        caseSensitive: true,
+        wholeWord: true,
+        regexMatch: true,
+      },
+      { isGlobal: true }
+    );
+
+    expect(query.source).toBe("\\bhi.*\\b");
+    expect(query.flags).toBe("g");
+    expect(query.ignoreCase).toBe(false);
+  });
+
+  it("case-insensitive, non-whole, string search", () => {
+    const query = buildQuery(
+      "hi",
+      {
+        caseSensitive: false,
+        wholeWord: false,
+        regexMatch: false,
+      },
+      {}
+    );
+
+    expect(query.source).toBe("hi");
+    expect(query.flags).toBe("i");
+    expect(query.ignoreCase).toBe(true);
+  });
+
+  it("case-insensitive, non-whole, string search, global", () => {
+    const query = buildQuery(
+      "hi",
+      {
+        caseSensitive: false,
+        wholeWord: false,
+        regexMatch: false,
+      },
+      { isGlobal: true }
+    );
+
+    expect(query.source).toBe("hi");
+    expect(query.flags).toBe("gi");
+    expect(query.ignoreCase).toBe(true);
+  });
+
+  it("case-sensitive string search", () => {
+    const query = buildQuery(
+      "hi",
+      {
+        caseSensitive: true,
+        wholeWord: false,
+        regexMatch: false,
+      },
+      {}
+    );
+
+    expect(query.source).toBe("hi");
+    expect(query.flags).toBe("");
+    expect(query.ignoreCase).toBe(false);
+  });
+
+  it("string search with wholeWord", () => {
+    const query = buildQuery(
+      "hi",
+      {
+        caseSensitive: false,
+        wholeWord: true,
+        regexMatch: false,
+      },
+      {}
+    );
+
+    expect(query.source).toBe("\\bhi\\b");
+    expect(query.flags).toBe("i");
+    expect(query.ignoreCase).toBe(true);
+  });
+
+  it("case-insensitive, regex search", () => {
+    const query = buildQuery(
+      "hi.*",
+      {
+        caseSensitive: false,
+        wholeWord: false,
+        regexMatch: true,
+      },
+      {}
+    );
+
+    expect(query.source).toBe("hi.*");
+    expect(query.flags).toBe("i");
+    expect(query.global).toBe(false);
+    expect(query.ignoreCase).toBe(true);
+  });
+
+  it("string search with wholeWord and case sensitivity", () => {
+    const query = buildQuery(
+      "hi",
+      {
+        caseSensitive: true,
+        wholeWord: true,
+        regexMatch: false,
+      },
+      {}
+    );
+
+    expect(query.source).toBe("\\bhi\\b");
+    expect(query.flags).toBe("");
+    expect(query.global).toBe(false);
+    expect(query.ignoreCase).toBe(false);
+  });
+
+  it("string search with wholeWord and case sensitivity, global", () => {
+    const query = buildQuery(
+      "hi",
+      {
+        caseSensitive: true,
+        wholeWord: true,
+        regexMatch: false,
+      },
+      { isGlobal: true }
+    );
+
+    expect(query.source).toBe("\\bhi\\b");
+    expect(query.flags).toBe("g");
+    expect(query.global).toBe(true);
+    expect(query.ignoreCase).toBe(false);
+  });
+
+  it("string search with regex chars escaped", () => {
+    const query = buildQuery(
+      "hi.*",
+      {
+        caseSensitive: true,
+        wholeWord: true,
+        regexMatch: false,
+      },
+      {}
+    );
+
+    expect(query.source).toBe("\\bhi\\.\\*\\b");
+    expect(query.flags).toBe("");
+    expect(query.global).toBe(false);
+    expect(query.ignoreCase).toBe(false);
+  });
+
+  it("string search with regex chars escaped, global", () => {
+    const query = buildQuery(
+      "hi.*",
+      {
+        caseSensitive: true,
+        wholeWord: true,
+        regexMatch: false,
+      },
+      { isGlobal: true }
+    );
+
+    expect(query.source).toBe("\\bhi\\.\\*\\b");
+    expect(query.flags).toBe("g");
+    expect(query.global).toBe(true);
+    expect(query.ignoreCase).toBe(false);
+  });
+
+  it("ignore spaces w/o spaces", () => {
+    const query = buildQuery(
+      "hi",
+      {
+        caseSensitive: true,
+        wholeWord: false,
+        regexMatch: false,
+      },
+      { ignoreSpaces: true }
+    );
+
+    expect(query.source).toBe("hi");
+    expect(query.flags).toBe("");
+    expect(query.global).toBe(false);
+    expect(query.ignoreCase).toBe(false);
+  });
+
+  it("ignore spaces w/o spaces, global", () => {
+    const query = buildQuery(
+      "hi",
+      {
+        caseSensitive: true,
+        wholeWord: false,
+        regexMatch: false,
+      },
+      { isGlobal: true, ignoreSpaces: true }
+    );
+
+    expect(query.source).toBe("hi");
+    expect(query.flags).toBe("g");
+    expect(query.global).toBe(true);
+    expect(query.ignoreCase).toBe(false);
+  });
+
+  it("ignore spaces w/ spaces", () => {
+    const query = buildQuery(
+      "  ",
+      {
+        caseSensitive: true,
+        wholeWord: false,
+        regexMatch: false,
+      },
+      { ignoreSpaces: true }
+    );
+
+    expect(query.source).toBe("(?!\\s*.*)");
+    expect(query.flags).toBe("");
+    expect(query.global).toBe(false);
+    expect(query.ignoreCase).toBe(false);
+  });
+
+  it("ignore spaces w/ spaces, global", () => {
+    const query = buildQuery(
+      "  ",
+      {
+        caseSensitive: true,
+        wholeWord: false,
+        regexMatch: false,
+      },
+      { isGlobal: true, ignoreSpaces: true }
+    );
+
+    expect(query.source).toBe("(?!\\s*.*)");
+    expect(query.flags).toBe("g");
+    expect(query.global).toBe(true);
+    expect(query.ignoreCase).toBe(false);
+  });
+});
diff --git a/devtools/client/debugger/src/utils/tests/clipboard.spec.js b/devtools/client/debugger/src/utils/tests/clipboard.spec.js
new file mode 100644
index 0000000000..dcba730149
--- /dev/null
+++ b/devtools/client/debugger/src/utils/tests/clipboard.spec.js
@@ -0,0 +1,45 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+import { copyToTheClipboard } from "../clipboard";
+
+let clipboardTestCopyString, expectedCopyEvent;
+const addEventListener = jest.fn();
+const execCommand = jest.fn();
+const removeEventListener = jest.fn();
+
+describe("copyToTheClipboard()", () => {
+  beforeEach(() => {
+    expectedCopyEvent = "copy";
+    clipboardTestCopyString = "content intended for clipboard";
+
+    global.document.addEventListener = addEventListener;
+    global.document.execCommand = execCommand;
+    global.document.removeEventListener = removeEventListener;
+  });
+
+  it("listens for 'copy' event", () => {
+    copyToTheClipboard(clipboardTestCopyString);
+
+    expect(document.addEventListener).toHaveBeenCalledWith(
+      expectedCopyEvent,
+      expect.anything()
+    );
+  });
+
+  it("calls document.execCommand() with 'copy' command", () => {
+    copyToTheClipboard(clipboardTestCopyString);
+
+    expect(execCommand).toHaveBeenCalledWith(expectedCopyEvent, false, null);
+  });
+
+  it("removes event listener for 'copy' event", () => {
+    copyToTheClipboard(clipboardTestCopyString);
+
+    expect(document.removeEventListener).toHaveBeenCalledWith(
+      expectedCopyEvent,
+      expect.anything()
+    );
+  });
+});
diff --git a/devtools/client/debugger/src/utils/tests/expressions.spec.js b/devtools/client/debugger/src/utils/tests/expressions.spec.js
new file mode 100644
index 0000000000..b7c91c4e07
--- /dev/null
+++ b/devtools/client/debugger/src/utils/tests/expressions.spec.js
@@ -0,0 +1,67 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+import {
+  wrapExpression,
+  getExpressionResultGripAndFront,
+} from "../expressions";
+import { makeMockExpression } from "../test-mockup";
+
+function createError(type, preview) {
+  return makeMockExpression({
+    result: { getGrip: () => ({ class: type, isError: true, preview }) },
+  });
+}
+
+describe("expressions", () => {
+  describe("wrap expression", () => {
+    it("should wrap an expression", () => {
+      expect(wrapExpression("foo")).toMatchSnapshot();
+    });
+
+    it("should wrap expression with a comment", () => {
+      expect(wrapExpression("foo // yo yo")).toMatchSnapshot();
+    });
+
+    it("should wrap quotes", () => {
+      expect(wrapExpression('"2"')).toMatchSnapshot();
+    });
+  });
+
+  describe("sanitize input", () => {
+    it("sanitizes quotes", () => {
+      expect('foo"').toEqual('foo"');
+    });
+
+    it("sanitizes 2 quotes", () => {
+      expect('"3"').toEqual('"3"');
+    });
+
+    it("evaluates \\u{61} as a", () => {
+      expect("\u{61}").toEqual("a");
+    });
+
+    it("evaluates N\\u{61}N as NaN", () => {
+      expect("N\u{61}N").toEqual("NaN");
+    });
+  });
+
+  describe("getValue", () => {
+    it("Reference Errors should be shown as (unavailable)", () => {
+      const { expressionResultGrip } = getExpressionResultGripAndFront(
+        createError("ReferenceError", { name: "ReferenceError" })
+      );
+      expect(expressionResultGrip).toEqual({
+        unavailable: true,
+      });
+    });
+
+    it("Errors messages should be shown", () => {
+      const { expressionResultGrip } = getExpressionResultGripAndFront(
+        createError("Error", { name: "Foo", message: "YO" })
+      );
+      expect(expressionResultGrip).toEqual("Foo: YO");
+    });
+  });
+});
diff --git a/devtools/client/debugger/src/utils/tests/function.spec.js b/devtools/client/debugger/src/utils/tests/function.spec.js
new file mode 100644
index 0000000000..db77736ab5
--- /dev/null
+++ b/devtools/client/debugger/src/utils/tests/function.spec.js
@@ -0,0 +1,61 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+import { findFunctionText } from "../function";
+
+import { getFunctionSymbols } from "../../workers/parser/getSymbols";
+import { populateOriginalSource } from "../../workers/parser/tests/helpers";
+
+describe("function", () => {
+  describe("findFunctionText", () => {
+    it("finds function", () => {
+      const source = populateOriginalSource("func");
+      const functions = getFunctionSymbols(source.id);
+      const text = findFunctionText(14, source, source.content, { functions });
+      expect(text).toMatchSnapshot();
+    });
+
+    it("finds function signature", () => {
+      const source = populateOriginalSource("func");
+      const functions = getFunctionSymbols(source.id);
+
+      const text = findFunctionText(13, source, source.content, { functions });
+      expect(text).toMatchSnapshot();
+    });
+
+    it("misses function closing brace", () => {
+      const source = populateOriginalSource("func");
+      const functions = getFunctionSymbols(source.id);
+
+      const text = findFunctionText(15, source, source.content, { functions });
+
+      // TODO: we should try and match the closing bracket.
+      expect(text).toEqual(null);
+    });
+
+    it("finds property function", () => {
+      const source = populateOriginalSource("func");
+      const functions = getFunctionSymbols(source.id);
+
+      const text = findFunctionText(29, source, source.content, { functions });
+      expect(text).toMatchSnapshot();
+    });
+
+    it("finds class function", () => {
+      const source = populateOriginalSource("func");
+      const functions = getFunctionSymbols(source.id);
+
+      const text = findFunctionText(33, source, source.content, { functions });
+      expect(text).toMatchSnapshot();
+    });
+
+    it("cant find function", () => {
+      const source = populateOriginalSource("func");
+      const functions = getFunctionSymbols(source.id);
+
+      const text = findFunctionText(20, source, source.content, { functions });
+      expect(text).toEqual(null);
+    });
+  });
+});
diff --git a/devtools/client/debugger/src/utils/tests/indentation.spec.js b/devtools/client/debugger/src/utils/tests/indentation.spec.js
new file mode 100644
index 0000000000..5ee7419371
--- /dev/null
+++ b/devtools/client/debugger/src/utils/tests/indentation.spec.js
@@ -0,0 +1,61 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+import { correctIndentation, getIndentation } from "../indentation";
+
+describe("indentation", () => {
+  it("simple", () => {
+    expect(
+      correctIndentation(`
+      foo
+    `)
+    ).toMatchSnapshot();
+  });
+
+  it("one line", () => {
+    expect(correctIndentation("foo")).toMatchSnapshot();
+  });
+
+  it("one function", () => {
+    const text = `
+      function foo() {
+        console.log("yo")
+      }
+    `;
+
+    expect(correctIndentation(text)).toMatchSnapshot();
+  });
+
+  it("try catch", () => {
+    const text = `
+      try {
+        console.log("yo")
+      } catch (e) {
+        console.log("yo")
+      }
+    `;
+
+    expect(correctIndentation(text)).toMatchSnapshot();
+  });
+
+  it("mad indentation", () => {
+    const text = `
+      try {
+        console.log("yo")
+      } catch (e) {
+        console.log("yo")
+          }
+    `;
+
+    expect(correctIndentation(text)).toMatchSnapshot();
+  });
+});
+
+describe("indentation length", () => {
+  it("leading spaces", () => {
+    const line = "                console.log('Hello World');";
+
+    expect(getIndentation(line)).toEqual(16);
+  });
+});
diff --git a/devtools/client/debugger/src/utils/tests/isMinified.spec.js b/devtools/client/debugger/src/utils/tests/isMinified.spec.js
new file mode 100644
index 0000000000..1c49f96737
--- /dev/null
+++ b/devtools/client/debugger/src/utils/tests/isMinified.spec.js
@@ -0,0 +1,18 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+import { isMinified } from "../isMinified";
+import { makeMockSourceWithContent } from "../test-mockup";
+
+describe("isMinified", () => {
+  it("no indents", () => {
+    const sourceWithContent = makeMockSourceWithContent(
+      undefined,
+      undefined,
+      undefined,
+      "function base(boo) {\n}"
+    );
+    expect(isMinified(sourceWithContent, sourceWithContent.content)).toBe(true);
+  });
+});
diff --git a/devtools/client/debugger/src/utils/tests/location.spec.js b/devtools/client/debugger/src/utils/tests/location.spec.js
new file mode 100644
index 0000000000..2be71f3cae
--- /dev/null
+++ b/devtools/client/debugger/src/utils/tests/location.spec.js
@@ -0,0 +1,31 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+import { sortSelectedLocations } from "../location";
+
+function loc(line, column) {
+  return {
+    location: { sourceId: "foo", line, column },
+    generatedLocation: { sourceId: "foo", line, column },
+  };
+}
+describe("location.spec.js", () => {
+  it("sorts lines", () => {
+    const a = loc(3, 5);
+    const b = loc(1, 10);
+    expect(sortSelectedLocations([a, b], { id: "foo" })).toEqual([b, a]);
+  });
+
+  it("sorts columns", () => {
+    const a = loc(3, 10);
+    const b = loc(3, 5);
+    expect(sortSelectedLocations([a, b], { id: "foo" })).toEqual([b, a]);
+  });
+
+  it("prioritizes undefined columns", () => {
+    const a = loc(3, 10);
+    const b = loc(3, undefined);
+    expect(sortSelectedLocations([a, b], { id: "foo" })).toEqual([b, a]);
+  });
+});
diff --git a/devtools/client/debugger/src/utils/tests/log.spec.js b/devtools/client/debugger/src/utils/tests/log.spec.js
new file mode 100644
index 0000000000..ea7e4ca4d2
--- /dev/null
+++ b/devtools/client/debugger/src/utils/tests/log.spec.js
@@ -0,0 +1,35 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+import { prefs } from "../prefs";
+import { log } from "../log.js";
+
+let logArgFirst, logArgSecond, logArgArray;
+
+describe("log()", () => {
+  beforeEach(() => {
+    logArgFirst = "my info";
+    logArgSecond = "my other info";
+    logArgArray = [logArgFirst, logArgSecond];
+    global.console = { log: jest.fn() };
+  });
+
+  afterEach(() => {
+    prefs.logging = false;
+  });
+
+  describe("when logging pref is true", () => {
+    it("prints arguments", () => {
+      prefs.logging = true;
+      log(logArgArray);
+
+      expect(global.console.log).toHaveBeenCalledWith(logArgArray);
+    });
+
+    it("does not print by default", () => {
+      log(logArgArray);
+      expect(global.console.log).not.toHaveBeenCalled();
+    });
+  });
+});
diff --git a/devtools/client/debugger/src/utils/tests/memoize.spec.js b/devtools/client/debugger/src/utils/tests/memoize.spec.js
new file mode 100644
index 0000000000..fb72958516
--- /dev/null
+++ b/devtools/client/debugger/src/utils/tests/memoize.spec.js
@@ -0,0 +1,48 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+import memoize from "../memoize";
+
+const a = { number: 3 };
+const b = { number: 4 };
+const c = { number: 5 };
+const d = { number: 6 };
+
+function add(...numberObjects) {
+  return numberObjects.reduce((prev, cur) => prev + cur.number, 0);
+}
+
+describe("memozie", () => {
+  it("should work for one arg as key", () => {
+    const mAdd = memoize(add);
+    mAdd(a);
+    expect(mAdd(a)).toEqual(3);
+    mAdd(b);
+    expect(mAdd(b)).toEqual(4);
+  });
+
+  it("should only be called once", () => {
+    const spy = jest.fn(() => 2);
+    const mAdd = memoize(spy);
+
+    mAdd(a);
+    mAdd(a);
+    mAdd(a);
+    expect(spy).toHaveBeenCalledTimes(1);
+  });
+
+  it("should work for two args as key", () => {
+    const mAdd = memoize(add);
+    expect(mAdd(a, b)).toEqual(7);
+    expect(mAdd(a, b)).toEqual(7);
+    expect(mAdd(a, c)).toEqual(8);
+  });
+
+  it("should work with many args as key", () => {
+    const mAdd = memoize(add);
+    expect(mAdd(a, b, c)).toEqual(12);
+    expect(mAdd(a, b, d)).toEqual(13);
+    expect(mAdd(a, b, c)).toEqual(12);
+  });
+});
diff --git a/devtools/client/debugger/src/utils/tests/memoizeLast.spec.js b/devtools/client/debugger/src/utils/tests/memoizeLast.spec.js
new file mode 100644
index 0000000000..a5622510e3
--- /dev/null
+++ b/devtools/client/debugger/src/utils/tests/memoizeLast.spec.js
@@ -0,0 +1,31 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+import { memoizeLast } from "../memoizeLast";
+
+const a = { number: 3 };
+const b = { number: 4 };
+
+function add(...numberObjects) {
+  return numberObjects.reduce((prev, cur) => prev + cur.number, 0);
+}
+
+describe("memozie", () => {
+  it("should re-calculate when a value changes", () => {
+    const mAdd = memoizeLast(add);
+    mAdd(a);
+    expect(mAdd(a)).toEqual(3);
+    mAdd(b);
+    expect(mAdd(b)).toEqual(4);
+  });
+
+  it("should only run once", () => {
+    const mockAdd = jest.fn(add);
+    const mAdd = memoizeLast(mockAdd);
+    mAdd(a);
+    mAdd(a);
+
+    expect(mockAdd.mock.calls[0]).toEqual([{ number: 3 }]);
+  });
+});
diff --git a/devtools/client/debugger/src/utils/tests/path.spec.js b/devtools/client/debugger/src/utils/tests/path.spec.js
new file mode 100644
index 0000000000..58bdf046f0
--- /dev/null
+++ b/devtools/client/debugger/src/utils/tests/path.spec.js
@@ -0,0 +1,49 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+import { basename, dirname, isURL, isAbsolute, join } from "../path";
+
+const fullTestURL = "https://www.example.com/some/endpoint";
+const absoluteTestPath = "/some/absolute/path/to/resource";
+const aTestName = "name";
+
+describe("basename()", () => {
+  it("returns the basename of the path", () => {
+    expect(basename(fullTestURL)).toBe("endpoint");
+  });
+});
+
+describe("dirname()", () => {
+  it("returns the current directory in a path", () => {
+    expect(dirname(fullTestURL)).toBe("https://www.example.com/some");
+  });
+});
+
+describe("isURL()", () => {
+  it("returns true if a string contains characters denoting a scheme", () => {
+    expect(isURL(fullTestURL)).toBe(true);
+  });
+
+  it("returns false if string does not denote a scheme", () => {
+    expect(isURL(absoluteTestPath)).toBe(false);
+  });
+});
+
+describe("isAbsolute()", () => {
+  it("returns true if a string begins with a slash", () => {
+    expect(isAbsolute(absoluteTestPath)).toBe(true);
+  });
+
+  it("returns false if a string does not begin with a slash", () => {
+    expect(isAbsolute(fullTestURL)).toBe(false);
+  });
+});
+
+describe("join()", () => {
+  it("concatenates a base path and a directory name", () => {
+    expect(join(absoluteTestPath, aTestName)).toBe(
+      "/some/absolute/path/to/resource/name"
+    );
+  });
+});
diff --git a/devtools/client/debugger/src/utils/tests/quick-open.spec.js b/devtools/client/debugger/src/utils/tests/quick-open.spec.js
new file mode 100644
index 0000000000..66cceb6825
--- /dev/null
+++ b/devtools/client/debugger/src/utils/tests/quick-open.spec.js
@@ -0,0 +1,35 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+import cases from "jest-in-case";
+import { parseQuickOpenQuery, parseLineColumn } from "../quick-open";
+
+cases(
+  "parseQuickOpenQuery utility",
+  ({ type, query }) => expect(parseQuickOpenQuery(query)).toEqual(type),
+  [
+    { name: "empty query defaults to sources", type: "sources", query: "" },
+    { name: "sources query", type: "sources", query: "test" },
+    { name: "functions query", type: "functions", query: "@test" },
+    { name: "variables query", type: "variables", query: "#test" },
+    { name: "goto line", type: "goto", query: ":30" },
+    { name: "goto line:column", type: "goto", query: ":30:60" },
+    { name: "goto source line", type: "gotoSource", query: "test:30:60" },
+    { name: "shortcuts", type: "shortcuts", query: "?" },
+  ]
+);
+
+cases(
+  "parseLineColumn utility",
+  ({ query, location }) => expect(parseLineColumn(query)).toEqual(location),
+  [
+    { name: "empty query", query: "", location: null },
+    { name: "just line", query: ":30", location: { line: 30 } },
+    {
+      name: "line and column",
+      query: ":30:90",
+      location: { column: 89, line: 30 },
+    },
+  ]
+);
diff --git a/devtools/client/debugger/src/utils/tests/result-list.spec.js b/devtools/client/debugger/src/utils/tests/result-list.spec.js
new file mode 100644
index 0000000000..dcbaf421c5
--- /dev/null
+++ b/devtools/client/debugger/src/utils/tests/result-list.spec.js
@@ -0,0 +1,32 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+import { scrollList } from "../result-list.js";
+
+describe("scrollList", () => {
+  beforeEach(() => {
+    jest.useFakeTimers();
+  });
+
+  /* eslint-disable jest/expect-expect */
+  it("just returns if element not found", () => {
+    const li = document.createElement("li");
+    scrollList([li], 1);
+  });
+  /* eslint-enable jest/expect-expect */
+
+  it("calls scrollIntoView", () => {
+    const ul = document.createElement("ul");
+    const li = document.createElement("li");
+
+    li.scrollIntoView = jest.fn();
+    ul.appendChild(li);
+
+    scrollList([li], 0);
+
+    jest.runAllTimers();
+
+    expect(li.scrollIntoView).toHaveBeenCalled();
+  });
+});
diff --git a/devtools/client/debugger/src/utils/tests/source.spec.js b/devtools/client/debugger/src/utils/tests/source.spec.js
new file mode 100644
index 0000000000..484c8ce570
--- /dev/null
+++ b/devtools/client/debugger/src/utils/tests/source.spec.js
@@ -0,0 +1,367 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+import {
+  getFilename,
+  getTruncatedFileName,
+  getFileURL,
+  getDisplayPath,
+  getSourceLineCount,
+  isJavaScript,
+  isDescendantOfRoot,
+  removeThreadActorId,
+  isUrlExtension,
+  getLineText,
+} from "../source.js";
+
+import {
+  makeMockSource,
+  makeMockSourceWithContent,
+  makeMockSourceAndContent,
+  makeMockWasmSourceWithContent,
+  makeMockThread,
+  makeFullfilledMockSourceContent,
+} from "../test-mockup";
+import { isFulfilled } from "../async-value.js";
+
+describe("sources", () => {
+  const unicode = "\u6e2c";
+  const encodedUnicode = encodeURIComponent(unicode);
+
+  describe("getFilename", () => {
+    it("should give us a default of (index)", () => {
+      expect(
+        getFilename(makeMockSource("http://localhost.com:7999/increment/"))
+      ).toBe("(index)");
+    });
+    it("should give us the filename", () => {
+      expect(
+        getFilename(
+          makeMockSource("http://localhost.com:7999/increment/hello.html")
+        )
+      ).toBe("hello.html");
+    });
+    it("should give us the readable Unicode filename if encoded", () => {
+      expect(
+        getFilename(
+          makeMockSource(
+            `http://localhost.com:7999/increment/${encodedUnicode}.html`
+          )
+        )
+      ).toBe(`${unicode}.html`);
+    });
+    it("should give us the filename excluding the query strings", () => {
+      expect(
+        getFilename(
+          makeMockSource(
+            "http://localhost.com:7999/increment/hello.html?query_strings"
+          )
+        )
+      ).toBe("hello.html");
+    });
+    it("should give us the proper filename for pretty files", () => {
+      expect(
+        getFilename(
+          makeMockSource(
+            "http://localhost.com:7999/increment/hello.html:formatted"
+          )
+        )
+      ).toBe("hello.html");
+    });
+  });
+
+  describe("getTruncatedFileName", () => {
+    it("should truncate the file name when it is more than 30 chars", () => {
+      expect(
+        getTruncatedFileName(
+          makeMockSource(
+            "really-really-really-really-really-really-long-name.html"
+          ),
+          "",
+          30
+        )
+      ).toBe("really-really…long-name.html");
+    });
+    it("should first decode the filename and then truncate it", () => {
+      expect(
+        getTruncatedFileName(
+          makeMockSource(`${encodedUnicode.repeat(30)}.html`),
+          "",
+          30
+        )
+      ).toBe("測測測測測測測測測測測測測…測測測測測測測測測.html");
+    });
+  });
+
+  describe("getDisplayPath", () => {
+    it("should give us the path for files with same name", () => {
+      const sources = [
+        makeMockSource("http://localhost.com:7999/increment/xyz/hello.html"),
+        makeMockSource("http://localhost.com:7999/increment/abc/hello.html"),
+        makeMockSource("http://localhost.com:7999/increment/hello.html"),
+      ];
+      expect(
+        getDisplayPath(
+          makeMockSource("http://localhost.com:7999/increment/abc/hello.html"),
+          sources
+        )
+      ).toBe("abc");
+    });
+
+    it(`should give us the path for files with same name
+      in directories with same name`, () => {
+      const sources = [
+        makeMockSource(
+          "http://localhost.com:7999/increment/xyz/web/hello.html"
+        ),
+        makeMockSource(
+          "http://localhost.com:7999/increment/abc/web/hello.html"
+        ),
+        makeMockSource("http://localhost.com:7999/increment/hello.html"),
+      ];
+      expect(
+        getDisplayPath(
+          makeMockSource(
+            "http://localhost.com:7999/increment/abc/web/hello.html"
+          ),
+          sources
+        )
+      ).toBe("abc/web");
+    });
+
+    it("should give no path for files with unique name", () => {
+      const sources = [
+        makeMockSource("http://localhost.com:7999/increment/xyz.html"),
+        makeMockSource("http://localhost.com:7999/increment/abc.html"),
+        makeMockSource("http://localhost.com:7999/increment/hello.html"),
+      ];
+      expect(
+        getDisplayPath(
+          makeMockSource("http://localhost.com:7999/increment/abc/web.html"),
+          sources
+        )
+      ).toBe(undefined);
+    });
+    it("should not show display path for pretty file", () => {
+      const sources = [
+        makeMockSource("http://localhost.com:7999/increment/abc/web/hell.html"),
+        makeMockSource(
+          "http://localhost.com:7999/increment/abc/web/hello.html"
+        ),
+        makeMockSource(
+          "http://localhost.com:7999/increment/xyz.html:formatted"
+        ),
+      ];
+      expect(
+        getDisplayPath(
+          makeMockSource(
+            "http://localhost.com:7999/increment/abc/web/hello.html:formatted"
+          ),
+          sources
+        )
+      ).toBe(undefined);
+    });
+    it(`should give us the path for files with same name when both
+      are pretty and different path`, () => {
+      const sources = [
+        makeMockSource(
+          "http://localhost.com:7999/increment/xyz/web/hello.html:formatted"
+        ),
+        makeMockSource(
+          "http://localhost.com:7999/increment/abc/web/hello.html:formatted"
+        ),
+        makeMockSource(
+          "http://localhost.com:7999/increment/hello.html:formatted"
+        ),
+      ];
+      expect(
+        getDisplayPath(
+          makeMockSource(
+            "http://localhost.com:7999/increment/abc/web/hello.html:formatted"
+          ),
+          sources
+        )
+      ).toBe("abc/web");
+    });
+  });
+
+  describe("getFileURL", () => {
+    it("should give us the file url", () => {
+      expect(
+        getFileURL(
+          makeMockSource("http://localhost.com:7999/increment/hello.html")
+        )
+      ).toBe("http://localhost.com:7999/increment/hello.html");
+    });
+    it("should truncate the file url when it is more than 50 chars", () => {
+      expect(
+        getFileURL(
+          makeMockSource("http://localhost-long.com:7999/increment/hello.html")
+        )
+      ).toBe("…ttp://localhost-long.com:7999/increment/hello.html");
+    });
+    it("should first decode the file URL and then truncate it", () => {
+      expect(
+        getFileURL(makeMockSource(`http://${encodedUnicode.repeat(39)}.html`))
+      ).toBe(`…ttp://${unicode.repeat(39)}.html`);
+    });
+  });
+
+  describe("isJavaScript", () => {
+    it("is not JavaScript", () => {
+      {
+        const source = makeMockSourceAndContent("foo.html", undefined, "");
+        expect(isJavaScript(source, source.content)).toBe(false);
+      }
+      {
+        const source = makeMockSourceAndContent(
+          undefined,
+          undefined,
+          "text/html"
+        );
+        expect(isJavaScript(source, source.content)).toBe(false);
+      }
+    });
+
+    it("is JavaScript", () => {
+      {
+        const source = makeMockSourceAndContent("foo.js");
+        expect(isJavaScript(source, source.content)).toBe(true);
+      }
+      {
+        const source = makeMockSourceAndContent("bar.jsm");
+        expect(isJavaScript(source, source.content)).toBe(true);
+      }
+      {
+        const source = makeMockSourceAndContent(
+          undefined,
+          undefined,
+          "text/javascript"
+        );
+        expect(isJavaScript(source, source.content)).toBe(true);
+      }
+      {
+        const source = makeMockSourceAndContent(
+          undefined,
+          undefined,
+          "application/javascript"
+        );
+        expect(isJavaScript(source, source.content)).toBe(true);
+      }
+    });
+  });
+
+  describe("getSourceLineCount", () => {
+    it("should give us the amount bytes for wasm source", () => {
+      const { content } = makeMockWasmSourceWithContent({
+        binary: "\x00asm\x01\x00\x00\x00",
+      });
+      expect(getSourceLineCount(content.value)).toEqual(8);
+    });
+
+    it("should give us the amout of lines for js source", () => {
+      const { content } = makeMockSourceWithContent(
+        undefined,
+        undefined,
+        "text/javascript",
+        "function foo(){\n}"
+      );
+      if (!content || !isFulfilled(content)) {
+        throw new Error("Unexpected content value");
+      }
+      expect(getSourceLineCount(content.value)).toEqual(2);
+    });
+  });
+
+  describe("isDescendantOfRoot", () => {
+    const threads = [
+      makeMockThread({ actor: "server0.conn1.child1/thread19" }),
+    ];
+
+    it("should detect normal source urls", () => {
+      const source = makeMockSource(
+        "resource://activity-stream/vendor/react.js"
+      );
+      const rootWithoutThreadActor = removeThreadActorId(
+        "resource://activity-stream",
+        threads
+      );
+      expect(isDescendantOfRoot(source, rootWithoutThreadActor)).toBe(true);
+    });
+
+    it("should detect source urls under chrome:// as root", () => {
+      const source = makeMockSource(
+        "chrome://browser/content/contentSearchUI.js"
+      );
+      const rootWithoutThreadActor = removeThreadActorId("chrome://", threads);
+      expect(isDescendantOfRoot(source, rootWithoutThreadActor)).toBe(true);
+    });
+
+    it("should detect source urls if root is a thread actor Id", () => {
+      const source = makeMockSource(
+        "resource://activity-stream/vendor/react-dom.js"
+      );
+      const rootWithoutThreadActor = removeThreadActorId(
+        "server0.conn1.child1/thread19",
+        threads
+      );
+      expect(isDescendantOfRoot(source, rootWithoutThreadActor)).toBe(true);
+    });
+  });
+
+  describe("isUrlExtension", () => {
+    it("should detect mozilla extension", () => {
+      expect(isUrlExtension("moz-extension://id/js/content.js")).toBe(true);
+    });
+    it("should detect chrome extension", () => {
+      expect(isUrlExtension("chrome-extension://id/js/content.js")).toBe(true);
+    });
+    it("should return false for non-extension assets", () => {
+      expect(isUrlExtension("https://example.org/init.js")).toBe(false);
+    });
+  });
+
+  describe("getLineText", () => {
+    it("first line", () => {
+      const text = getLineText(
+        "fake-source",
+        makeFullfilledMockSourceContent("aaa\nbbb\nccc"),
+        1
+      );
+
+      expect(text).toEqual("aaa");
+    });
+
+    it("last line", () => {
+      const text = getLineText(
+        "fake-source",
+        makeFullfilledMockSourceContent("aaa\nbbb\nccc"),
+        3
+      );
+
+      expect(text).toEqual("ccc");
+    });
+
+    it("one line", () => {
+      const text = getLineText(
+        "fake-source",
+        makeFullfilledMockSourceContent("aaa"),
+        1
+      );
+
+      expect(text).toEqual("aaa");
+    });
+
+    it("bad line", () => {
+      const text = getLineText(
+        "fake-source",
+        makeFullfilledMockSourceContent("aaa\nbbb\nccc"),
+
+        5
+      );
+
+      expect(text).toEqual("");
+    });
+  });
+});
diff --git a/devtools/client/debugger/src/utils/tests/telemetry.spec.js b/devtools/client/debugger/src/utils/tests/telemetry.spec.js
new file mode 100644
index 0000000000..7223641afd
--- /dev/null
+++ b/devtools/client/debugger/src/utils/tests/telemetry.spec.js
@@ -0,0 +1,13 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+import { recordEvent } from "../telemetry";
+
+describe("telemetry.recordEvent()", () => {
+  it("Receives the correct telemetry information", () => {
+    recordEvent("foo", { bar: 1 });
+
+    expect(window.dbg._telemetry.events.foo).toStrictEqual([{ bar: 1 }]);
+  });
+});
diff --git a/devtools/client/debugger/src/utils/tests/text.spec.js b/devtools/client/debugger/src/utils/tests/text.spec.js
new file mode 100644
index 0000000000..5786bc6232
--- /dev/null
+++ b/devtools/client/debugger/src/utils/tests/text.spec.js
@@ -0,0 +1,20 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+import { truncateMiddleText } from "../text";
+
+describe("text", () => {
+  it("should truncate the text in the middle", () => {
+    const sourceText = "this is a very long text and ends here";
+    expect(truncateMiddleText(sourceText, 30)).toMatch(
+      "this is a ver… and ends here"
+    );
+  });
+  it("should keep the text as it is", () => {
+    const sourceText = "this is a short text ends here";
+    expect(truncateMiddleText(sourceText, 30)).toMatch(
+      "this is a short text ends here"
+    );
+  });
+});
diff --git a/devtools/client/debugger/src/utils/tests/ui.spec.js b/devtools/client/debugger/src/utils/tests/ui.spec.js
new file mode 100644
index 0000000000..aa091e6798
--- /dev/null
+++ b/devtools/client/debugger/src/utils/tests/ui.spec.js
@@ -0,0 +1,15 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+import { isVisible } from "../ui";
+
+describe("ui", () => {
+  it("should return #mount width", () => {
+    if (!document.body) {
+      throw new Error("no document body");
+    }
+    document.body.innerHTML = "<div id='mount'></div>";
+    expect(isVisible()).toBe(false);
+  });
+});
diff --git a/devtools/client/debugger/src/utils/tests/url.spec.js b/devtools/client/debugger/src/utils/tests/url.spec.js
new file mode 100644
index 0000000000..d842acf7db
--- /dev/null
+++ b/devtools/client/debugger/src/utils/tests/url.spec.js
@@ -0,0 +1,89 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+import { parse } from "../url";
+
+describe("url", () => {
+  describe("parse", () => {
+    it("parses an absolute URL", () => {
+      const val = parse("http://example.com:8080/path/file.js");
+
+      expect(val.protocol).toBe("http:");
+      expect(val.host).toBe("example.com:8080");
+      expect(val.pathname).toBe("/path/file.js");
+      expect(val.search).toBe("");
+      expect(val.hash).toBe("");
+    });
+
+    it("parses an absolute URL with query params", () => {
+      const val = parse("http://example.com:8080/path/file.js?param");
+
+      expect(val.protocol).toBe("http:");
+      expect(val.host).toBe("example.com:8080");
+      expect(val.pathname).toBe("/path/file.js");
+      expect(val.search).toBe("?param");
+      expect(val.hash).toBe("");
+    });
+
+    it("parses an absolute URL with a fragment", () => {
+      const val = parse("http://example.com:8080/path/file.js#hash");
+
+      expect(val.protocol).toBe("http:");
+      expect(val.host).toBe("example.com:8080");
+      expect(val.pathname).toBe("/path/file.js");
+      expect(val.search).toBe("");
+      expect(val.hash).toBe("#hash");
+    });
+
+    it("parses an absolute URL with query params and a fragment", () => {
+      const val = parse("http://example.com:8080/path/file.js?param#hash");
+
+      expect(val.protocol).toBe("http:");
+      expect(val.host).toBe("example.com:8080");
+      expect(val.pathname).toBe("/path/file.js");
+      expect(val.search).toBe("?param");
+      expect(val.hash).toBe("#hash");
+    });
+
+    it("parses a partial URL", () => {
+      const val = parse("/path/file.js");
+
+      expect(val.protocol).toBe("");
+      expect(val.host).toBe("");
+      expect(val.pathname).toBe("/path/file.js");
+      expect(val.search).toBe("");
+      expect(val.hash).toBe("");
+    });
+
+    it("parses a partial URL with query params", () => {
+      const val = parse("/path/file.js?param");
+
+      expect(val.protocol).toBe("");
+      expect(val.host).toBe("");
+      expect(val.pathname).toBe("/path/file.js");
+      expect(val.search).toBe("?param");
+      expect(val.hash).toBe("");
+    });
+
+    it("parses a partial URL with a fragment", () => {
+      const val = parse("/path/file.js#hash");
+
+      expect(val.protocol).toBe("");
+      expect(val.host).toBe("");
+      expect(val.pathname).toBe("/path/file.js");
+      expect(val.search).toBe("");
+      expect(val.hash).toBe("#hash");
+    });
+
+    it("parses a partial URL with query params and a fragment", () => {
+      const val = parse("/path/file.js?param#hash");
+
+      expect(val.protocol).toBe("");
+      expect(val.host).toBe("");
+      expect(val.pathname).toBe("/path/file.js");
+      expect(val.search).toBe("?param");
+      expect(val.hash).toBe("#hash");
+    });
+  });
+});
diff --git a/devtools/client/debugger/src/utils/tests/utils.spec.js b/devtools/client/debugger/src/utils/tests/utils.spec.js
new file mode 100644
index 0000000000..f358ffc42a
--- /dev/null
+++ b/devtools/client/debugger/src/utils/tests/utils.spec.js
@@ -0,0 +1,87 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+import { handleError, promisify, endTruncateStr, waitForMs } from "../utils";
+
+describe("handleError()", () => {
+  const testErrorText = "ERROR: ";
+  const testErrorObject = { oh: "noes" };
+
+  beforeEach(() => {
+    global.console = { log: jest.fn() };
+  });
+
+  it("logs error text with error value", () => {
+    handleError(testErrorObject);
+
+    expect(console.log).toHaveBeenCalledWith(testErrorText, testErrorObject);
+  });
+});
+
+describe("promisify()", () => {
+  let testPromise, testContext, testMethod, testArgs;
+
+  beforeEach(() => {
+    testContext = {};
+    testMethod = jest.fn();
+    testArgs = [];
+  });
+
+  it("returns a Promise", () => {
+    testPromise = promisify(testContext, testMethod, testArgs);
+
+    expect(testPromise instanceof Promise).toBe(true);
+  });
+
+  it("applies promisified method", () => {
+    testPromise = promisify(testContext, testMethod, testArgs);
+
+    expect(testMethod).toHaveBeenCalledWith(testArgs, expect.anything());
+  });
+});
+
+describe("endTruncateStr()", () => {
+  let testString;
+  const testSize = 11;
+
+  describe("when the string is larger than the specified size", () => {
+    it("returns an elipsis and characters at the end of the string", () => {
+      testString = "Mozilla Firefox is my favorite web browser";
+
+      expect(endTruncateStr(testString, testSize)).toBe("…web browser");
+    });
+  });
+
+  describe("when the string is not larger than the specified size", () => {
+    it("returns the string unchanged", () => {
+      testString = "Firefox";
+
+      expect(endTruncateStr(testString, testSize)).toBe(testString);
+    });
+  });
+});
+
+describe("waitForMs()", () => {
+  let testPromise;
+  const testMilliseconds = 10;
+
+  beforeEach(() => {
+    global.setTimeout = jest.fn();
+  });
+
+  it("returns a Promise", () => {
+    testPromise = waitForMs(testMilliseconds);
+
+    expect(testPromise instanceof Promise).toBe(true);
+  });
+
+  it("calls setTimeout() on the resolve of the Promise", () => {
+    testPromise = waitForMs(testMilliseconds);
+
+    expect(setTimeout).toHaveBeenCalledWith(
+      expect.anything(),
+      testMilliseconds
+    );
+  });
+});
diff --git a/devtools/client/debugger/src/utils/tests/wasm.spec.js b/devtools/client/debugger/src/utils/tests/wasm.spec.js
new file mode 100644
index 0000000000..6cf3b1083b
--- /dev/null
+++ b/devtools/client/debugger/src/utils/tests/wasm.spec.js
@@ -0,0 +1,96 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+import {
+  isWasm,
+  lineToWasmOffset,
+  wasmOffsetToLine,
+  clearWasmStates,
+  renderWasmText,
+} from "../wasm.js";
+
+import { makeMockWasmSourceWithContent } from "../test-mockup";
+
+describe("wasm", () => {
+  // Compiled version of `(module (func (nop)))`
+  const SIMPLE_WASM = {
+    binary:
+      "\x00asm\x01\x00\x00\x00\x01\x84\x80\x80\x80\x00\x01`\x00\x00" +
+      "\x03\x82\x80\x80\x80\x00\x01\x00\x06\x81\x80\x80\x80\x00\x00" +
+      "\n\x89\x80\x80\x80\x00\x01\x83\x80\x80\x80\x00\x00\x01\v",
+  };
+
+  // malformed binary which contains an unknown operator (\x09) which
+  // should cause the wasm parser to throw.
+  const MALFORMED_SIMPLE_WASM = {
+    binary:
+      "\x00asm\x01\x00\x00\x00\x09\x84\x80\x80\x80\x00\x01`\x00\x00" +
+      "\x03\x82\x80\x80\x80\x00\x01\x00\x06\x81\x80\x80\x80\x00\x00" +
+      "\n\x89\x80\x80\x80\x00\x01\x83\x80\x80\x80\x00\x00\x01\v",
+  };
+
+  const SIMPLE_WASM_TEXT = `(module
+  (func $func0
+    nop
+  )
+)`;
+  const SIMPLE_WASM_NOP_TEXT_LINE = 2;
+  const SIMPLE_WASM_NOP_OFFSET = 46;
+
+  describe("isWasm", () => {
+    it("should give us the false when wasm text was not registered", () => {
+      const sourceId = "source.0";
+      expect(isWasm(sourceId)).toEqual(false);
+    });
+    it("should give us the true when wasm text was registered", () => {
+      const source = makeMockWasmSourceWithContent(SIMPLE_WASM);
+      renderWasmText(source.id, source.content.value);
+      expect(isWasm(source.id)).toEqual(true);
+      // clear shall remove
+      clearWasmStates();
+      expect(isWasm(source.id)).toEqual(false);
+    });
+  });
+
+  describe("renderWasmText", () => {
+    it("render simple wasm", () => {
+      const source = makeMockWasmSourceWithContent(SIMPLE_WASM);
+      const lines = renderWasmText(source.id, source.content.value);
+      expect(lines.join("\n")).toEqual(SIMPLE_WASM_TEXT);
+      clearWasmStates();
+    });
+
+    it("should return error information when the parser throws", () => {
+      const source = makeMockWasmSourceWithContent(MALFORMED_SIMPLE_WASM);
+      const lines = renderWasmText(source.id, source.content.value);
+      expect(lines.join("\n")).toEqual(
+        "Error occured during wast conversion : Unsupported element segment type 96"
+      );
+      clearWasmStates();
+    });
+  });
+
+  describe("lineToWasmOffset", () => {
+    // Test data sanity check: checking if 'nop' is found in the SIMPLE_WASM.
+    expect(SIMPLE_WASM.binary[SIMPLE_WASM_NOP_OFFSET]).toEqual("\x01");
+
+    it("get simple wasm nop offset", () => {
+      const source = makeMockWasmSourceWithContent(SIMPLE_WASM);
+      renderWasmText(source.id, source.content.value);
+      const offset = lineToWasmOffset(source.id, SIMPLE_WASM_NOP_TEXT_LINE);
+      expect(offset).toEqual(SIMPLE_WASM_NOP_OFFSET);
+      clearWasmStates();
+    });
+  });
+
+  describe("wasmOffsetToLine", () => {
+    it("get simple wasm nop line", () => {
+      const source = makeMockWasmSourceWithContent(SIMPLE_WASM);
+      renderWasmText(source.id, source.content.value);
+      const line = wasmOffsetToLine(source.id, SIMPLE_WASM_NOP_OFFSET);
+      expect(line).toEqual(SIMPLE_WASM_NOP_TEXT_LINE);
+      clearWasmStates();
+    });
+  });
+});