1 files changed, 173 insertions, 0 deletions
diff --git a/toolkit/components/extensions/test/xpcshell/test_ext_startup_cache_telemetry.js b/toolkit/components/extensions/test/xpcshell/test_ext_startup_cache_telemetry.js
new file mode 100644
index 0000000000..7ceec46679
--- /dev/null
+++ b/toolkit/components/extensions/test/xpcshell/test_ext_startup_cache_telemetry.js
@@ -0,0 +1,173 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+ChromeUtils.defineESModuleGetters(this, {
+  ExtensionParent: "resource://gre/modules/ExtensionParent.sys.mjs",
+  TelemetryTestUtils: "resource://testing-common/TelemetryTestUtils.sys.mjs",
+});
+
+AddonTestUtils.init(this);
+AddonTestUtils.overrideCertDB();
+
+AddonTestUtils.createAppInfo(
+  "xpcshell@tests.mozilla.org",
+  "XPCShell",
+  "42",
+  "42"
+);
+
+const ADDON_ID = "test-startup-cache-telemetry@xpcshell.mozilla.org";
+
+add_setup(async () => {
+  // FOG needs a profile directory to put its data in.
+  do_get_profile();
+  // FOG needs to be initialized in order for data to flow.
+  Services.fog.initializeFOG();
+
+  await AddonTestUtils.promiseStartupManager();
+});
+
+add_task(async function test_startupCache_write_byteLength() {
+  Services.fog.testResetFOG();
+  const extension = ExtensionTestUtils.loadExtension({
+    useAddonManager: "permanent",
+    manifest: {
+      browser_specific_settings: { gecko: { id: ADDON_ID } },
+    },
+  });
+
+  await extension.startup();
+
+  const { StartupCache } = ExtensionParent;
+
+  const aomStartup = Cc[
+    "@mozilla.org/addons/addon-manager-startup;1"
+  ].getService(Ci.amIAddonManagerStartup);
+
+  let expectedByteLength = new Uint8Array(
+    aomStartup.encodeBlob(StartupCache._data)
+  ).byteLength;
+
+  equal(
+    typeof expectedByteLength,
+    "number",
+    "Got a numeric byteLength for the expected startupCache data"
+  );
+  Assert.greater(
+    expectedByteLength,
+    0,
+    "Got a non-zero byteLength as expected"
+  );
+  await StartupCache._saveNow();
+
+  let scalars = TelemetryTestUtils.getProcessScalars("parent");
+  equal(
+    scalars["extensions.startupCache.write_byteLength"],
+    expectedByteLength,
+    "Got the expected value set in the 'extensions.startupCache.write_byteLength' scalar"
+  );
+  equal(
+    Glean.extensions.startupCacheWriteBytelength.testGetValue(),
+    expectedByteLength,
+    "Expected 'extensions.startupCache.write_byteLength' Glean metric."
+  );
+
+  await extension.unload();
+});
+
+add_task(async function test_startupCache_read_errors() {
+  const { StartupCache } = ExtensionParent;
+
+  // Clear any pre-existing keyed scalar.
+  TelemetryTestUtils.getProcessScalars("parent", /* keyed */ true, true);
+  Services.fog.testResetFOG();
+
+  // Temporarily point StartupCache._file to a path that is
+  // not going to exist for sure.
+  Assert.notEqual(
+    StartupCache.file,
+    null,
+    "Got a StartupCache._file non-null property as expected"
+  );
+  const oldFile = StartupCache.file;
+  const restoreStartupCacheFile = () => (StartupCache.file = oldFile);
+  StartupCache.file = `${StartupCache.file}.non_existing_file.${Math.random()}`;
+  registerCleanupFunction(restoreStartupCacheFile);
+
+  // Make sure the _readData has been called and we can expect
+  // the extensions.startupCache.read_errors scalar to have
+  // been recorded.
+  await StartupCache._readData();
+
+  let scalars = TelemetryTestUtils.getProcessScalars(
+    "parent",
+    /* keyed */ true
+  );
+  Assert.deepEqual(
+    scalars["extensions.startupCache.read_errors"],
+    {
+      NotFoundError: 1,
+    },
+    "Got the expected value set in the 'extensions.startupCache.read_errors' keyed scalar"
+  );
+  Assert.deepEqual(
+    Glean.extensions.startupCacheReadErrors.NotFoundError.testGetValue(),
+    1,
+    "Expected value for 'extensions.startupCache.read_errors' Glean metric."
+  );
+
+  restoreStartupCacheFile();
+});
+
+add_task(async function test_startupCache_load_timestamps() {
+  const { StartupCache } = ExtensionParent;
+
+  // Clear any pre-existing keyed scalar and Glean metrics data.
+  Services.telemetry.getSnapshotForScalars("main", true);
+  Services.fog.testResetFOG();
+
+  let gleanMetric = Glean.extensions.startupCacheLoadTime.testGetValue();
+  equal(
+    gleanMetric,
+    null,
+    "Expect extensions.startup_cache_load_time Glean metric to be initially null"
+  );
+
+  // Make sure the _readData has been called and we can expect
+  // the startupCache load telemetry timestamps to have been
+  // recorded.
+  await StartupCache._readData();
+
+  info(
+    "Verify telemetry recorded for the 'extensions.startup_cache_load_time' Glean metric"
+  );
+
+  gleanMetric = Glean.extensions.startupCacheLoadTime.testGetValue();
+  equal(
+    typeof gleanMetric,
+    "number",
+    "Expect extensions.startup_cache_load_time Glean metric to be set to a number"
+  );
+
+  info(
+    "Verify telemetry mirrored into the 'extensions.startupCache.load_time' scalar"
+  );
+
+  const scalars = TelemetryTestUtils.getProcessScalars("parent", false, true);
+  const mirror = scalars["extensions.startupCache.load_time"];
+
+  equal(
+    typeof mirror,
+    "number",
+    "Expect extensions.startupCache.load_time mirrored scalar to be set to a number"
+  );
+
+  // See https://bugzilla.mozilla.org/show_bug.cgi?id=1865850.
+  Assert.lessOrEqual(
+    Math.abs(gleanMetric - mirror),
+    1,
+    `Expect Glean metric ${gleanMetric} and mirrored scalar ${mirror} to be within 1ms of each other.`
+  );
+});