1 files changed, 100 insertions, 0 deletions
diff --git a/devtools/client/inspector/fonts/test/browser_fontinspector_reveal-in-page.js b/devtools/client/inspector/fonts/test/browser_fontinspector_reveal-in-page.js
new file mode 100644
index 0000000000..bcefe0b3bf
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+++ b/devtools/client/inspector/fonts/test/browser_fontinspector_reveal-in-page.js
@@ -0,0 +1,100 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
+
+// Test that fonts usage can be revealed in the page using the FontsHighlighter.
+
+const TEST_URI = URL_ROOT + "doc_browser_fontinspector.html";
+
+add_task(async function () {
+  // Make sure the toolbox is tall enough to accomodate all fonts, otherwise mouseover
+  // events simulation will fail.
+  await pushPref("devtools.toolbox.footer.height", 500);
+
+  const { view } = await openFontInspectorForURL(TEST_URI);
+  await testFontHighlighting(view);
+
+  info("Check that highlighting still works after reloading the page");
+  await reloadBrowser();
+  await testFontHighlighting(view);
+});
+
+async function testFontHighlighting(view) {
+  // The number of window selection change events we expect to get as we hover over each
+  // font in the list. Waiting for those events is how we know that text-runs were
+  // highlighted in the page.
+  // The reason why these numbers vary is because the highlighter may create more than
+  // 1 selection range object, depending on the number of text-runs found.
+  const expectedSelectionChangeEvents = [2, 2, 2, 1, 1];
+
+  const viewDoc = view.document;
+
+  // Wait for the view to have all the expected used fonts.
+  const fontEls = await waitFor(() => {
+    const els = getUsedFontsEls(viewDoc);
+    if (els.length !== expectedSelectionChangeEvents.length) {
+      return false;
+    }
+
+    return els;
+  });
+
+  for (let i = 0; i < fontEls.length; i++) {
+    info(
+      `Mousing over and out of font number ${i} ("${fontEls[i].textContent}") in the list`
+    );
+
+    // Simulating a mouse over event on the font name and expecting a selectionchange.
+    const nameEl = fontEls[i];
+    let onEvents = waitForNSelectionEvents(expectedSelectionChangeEvents[i]);
+    EventUtils.synthesizeMouse(
+      nameEl,
+      2,
+      2,
+      { type: "mouseover" },
+      viewDoc.defaultView
+    );
+    await onEvents;
+
+    ok(
+      true,
+      `${expectedSelectionChangeEvents[i]} selectionchange events detected on mouseover`
+    );
+
+    // Simulating a mouse out event on the font name and expecting a selectionchange.
+    const otherEl = viewDoc.querySelector("body");
+    onEvents = waitForNSelectionEvents(1);
+    EventUtils.synthesizeMouse(
+      otherEl,
+      2,
+      2,
+      { type: "mouseover" },
+      viewDoc.defaultView
+    );
+    await onEvents;
+
+    ok(true, "1 selectionchange events detected on mouseout");
+  }
+}
+
+async function waitForNSelectionEvents(numberOfTimes) {
+  await SpecialPowers.spawn(
+    gBrowser.selectedBrowser,
+    [numberOfTimes],
+    async function (n) {
+      const win = content.wrappedJSObject;
+
+      await new Promise(resolve => {
+        let received = 0;
+        win.document.addEventListener("selectionchange", function listen() {
+          received++;
+
+          if (received === n) {
+            win.document.removeEventListener("selectionchange", listen);
+            resolve();
+          }
+        });
+      });
+    }
+  );
+}