1 files changed, 45 insertions, 0 deletions
diff --git a/browser/components/sessionstore/test/browser_bfcache_telemetry.js b/browser/components/sessionstore/test/browser_bfcache_telemetry.js
new file mode 100644
index 0000000000..daa4bcf44e
--- /dev/null
+++ b/browser/components/sessionstore/test/browser_bfcache_telemetry.js
@@ -0,0 +1,45 @@
+const URL1 = "data:text/html;charset=utf-8,<body><p>Hello1</p></body>";
+const URL2 = "data:text/html;charset=utf-8,<body><p>Hello2</p></body>";
+
+async function getBFCacheComboTelemetry(probeInParent) {
+  let bfcacheCombo;
+  await TestUtils.waitForCondition(() => {
+    let histograms;
+    if (probeInParent) {
+      histograms = Services.telemetry.getSnapshotForHistograms(
+        "main",
+        false /* clear */
+      ).parent;
+    } else {
+      histograms = Services.telemetry.getSnapshotForHistograms(
+        "main",
+        false /* clear */
+      ).content;
+    }
+    bfcacheCombo = histograms.BFCACHE_COMBO;
+    return bfcacheCombo;
+  });
+  return bfcacheCombo;
+}
+
+async function test_bfcache_telemetry(probeInParent) {
+  Services.telemetry.getHistogramById("BFCACHE_COMBO").clear();
+
+  let tab = await BrowserTestUtils.openNewForegroundTab(gBrowser, URL1);
+
+  BrowserTestUtils.loadURIString(tab.linkedBrowser, URL2);
+  await BrowserTestUtils.browserLoaded(tab.linkedBrowser);
+
+  let bfcacheCombo = await getBFCacheComboTelemetry(probeInParent);
+
+  is(bfcacheCombo.values[0], 1, "1 bfcache success");
+
+  gBrowser.removeTab(tab);
+}
+
+add_task(async () => {
+  await test_bfcache_telemetry(
+    Services.appinfo.sessionHistoryInParent &&
+      Services.prefs.getBoolPref("fission.bfcacheInParent")
+  );
+});