1 files changed, 112 insertions, 0 deletions
diff --git a/browser/base/content/test/tabs/browser_tabCloseProbes.js b/browser/base/content/test/tabs/browser_tabCloseProbes.js
new file mode 100644
index 0000000000..4e5aca8482
--- /dev/null
+++ b/browser/base/content/test/tabs/browser_tabCloseProbes.js
@@ -0,0 +1,112 @@
+"use strict";
+
+var gAnimHistogram = Services.telemetry.getHistogramById(
+  "FX_TAB_CLOSE_TIME_ANIM_MS"
+);
+var gNoAnimHistogram = Services.telemetry.getHistogramById(
+  "FX_TAB_CLOSE_TIME_NO_ANIM_MS"
+);
+
+/**
+ * Takes a Telemetry histogram snapshot and returns the sum of all counts.
+ *
+ * @param snapshot (Object)
+ *        The Telemetry histogram snapshot to examine.
+ * @return (int)
+ *         The sum of all counts in the snapshot.
+ */
+function snapshotCount(snapshot) {
+  // Use Array.prototype.reduce to sum up all of the
+  // snapshot.count entries
+  return Object.values(snapshot.values).reduce((a, b) => a + b, 0);
+}
+
+/**
+ * Takes a Telemetry histogram snapshot and makes sure
+ * that the sum of all counts equals expectedCount.
+ *
+ * @param snapshot (Object)
+ *        The Telemetry histogram snapshot to examine.
+ * @param expectedCount (int)
+ *        What we expect the number of incremented counts to be. For example,
+ *        If we expect this probe to have only had a single recording, this
+ *        would be 1. If we expected it to have not recorded any data at all,
+ *        this would be 0.
+ */
+function assertCount(snapshot, expectedCount) {
+  Assert.equal(
+    snapshotCount(snapshot),
+    expectedCount,
+    `Should only be ${expectedCount} collected value.`
+  );
+}
+
+/**
+ * Takes a Telemetry histogram and waits for the sum of all counts becomes
+ * equal to expectedCount.
+ *
+ * @param histogram (Object)
+ *        The Telemetry histogram to examine.
+ * @param expectedCount (int)
+ *        What we expect the number of incremented counts to become.
+ * @return (Promise)
+ * @resolves When the histogram snapshot count becomes the expected count.
+ */
+function waitForSnapshotCount(histogram, expectedCount) {
+  return BrowserTestUtils.waitForCondition(() => {
+    return snapshotCount(histogram.snapshot()) == expectedCount;
+  }, `Collected value should become ${expectedCount}.`);
+}
+
+add_setup(async function () {
+  // Force-enable tab animations
+  gReduceMotionOverride = false;
+
+  // These probes are opt-in, meaning we only capture them if extended
+  // Telemetry recording is enabled.
+  let oldCanRecord = Services.telemetry.canRecordExtended;
+  Services.telemetry.canRecordExtended = true;
+  registerCleanupFunction(() => {
+    Services.telemetry.canRecordExtended = oldCanRecord;
+  });
+});
+
+/**
+ * Tests the FX_TAB_CLOSE_TIME_ANIM_MS probe by closing a tab with the tab
+ * close animation.
+ */
+add_task(async function test_close_time_anim_probe() {
+  let tab = await BrowserTestUtils.openNewForegroundTab(gBrowser);
+  await BrowserTestUtils.waitForCondition(() => tab._fullyOpen);
+
+  gAnimHistogram.clear();
+  gNoAnimHistogram.clear();
+
+  BrowserTestUtils.removeTab(tab, { animate: true });
+
+  await waitForSnapshotCount(gAnimHistogram, 1);
+  assertCount(gNoAnimHistogram.snapshot(), 0);
+
+  gAnimHistogram.clear();
+  gNoAnimHistogram.clear();
+});
+
+/**
+ * Tests the FX_TAB_CLOSE_TIME_NO_ANIM_MS probe by closing a tab without the
+ * tab close animation.
+ */
+add_task(async function test_close_time_no_anim_probe() {
+  let tab = await BrowserTestUtils.openNewForegroundTab(gBrowser);
+  await BrowserTestUtils.waitForCondition(() => tab._fullyOpen);
+
+  gAnimHistogram.clear();
+  gNoAnimHistogram.clear();
+
+  BrowserTestUtils.removeTab(tab, { animate: false });
+
+  await waitForSnapshotCount(gNoAnimHistogram, 1);
+  assertCount(gAnimHistogram.snapshot(), 0);
+
+  gAnimHistogram.clear();
+  gNoAnimHistogram.clear();
+});