Bug 1794409 - Tests for Telemetry on Utility r=chutten

Differential Revision: https://phabricator.services.mozilla.com/D159042

ipc/glue/PUtilityProcess.ipdl

@@ -78,6 +78,8 @@ child:
   // The unused returned value is to have a promise we can await.
   async TestTriggerMetrics() returns (bool unused);
 
+  async TestTelemetryProbes();
+
   async StartUtilityAudioDecoderService(Endpoint<PUtilityAudioDecoderParent> aEndpoint);
 
 #if defined(MOZ_SANDBOX) && defined(MOZ_DEBUG) && defined(ENABLE_TESTS)

ipc/glue/UtilityProcessChild.cpp

@@ -214,6 +214,13 @@ mozilla::ipc::IPCResult UtilityProcessChild::RecvTestTriggerMetrics(
   return IPC_OK();
 }
 
+mozilla::ipc::IPCResult UtilityProcessChild::RecvTestTelemetryProbes() {
+  const uint32_t kExpectedUintValue = 42;
+  Telemetry::ScalarSet(Telemetry::ScalarID::TELEMETRY_TEST_UTILITY_ONLY_UINT,
+                       kExpectedUintValue);
+  return IPC_OK();
+}
+
 mozilla::ipc::IPCResult
 UtilityProcessChild::RecvStartUtilityAudioDecoderService(
     Endpoint<PUtilityAudioDecoderParent>&& aEndpoint) {

ipc/glue/UtilityProcessChild.h

@@ -50,6 +50,8 @@ class UtilityProcessChild final : public PUtilityProcessChild {
   mozilla::ipc::IPCResult RecvTestTriggerMetrics(
       TestTriggerMetricsResolver&& aResolve);
 
+  mozilla::ipc::IPCResult RecvTestTelemetryProbes();
+
   mozilla::ipc::IPCResult RecvStartUtilityAudioDecoderService(
       Endpoint<PUtilityAudioDecoderParent>&& aEndpoint);
 

ipc/glue/test/utility_process_xpcom/UtilityProcessTest.cpp

@@ -78,6 +78,20 @@ UtilityProcessTest::StopProcess() {
   return NS_OK;
 }
 
+NS_IMETHODIMP
+UtilityProcessTest::TestTelemetryProbes() {
+  RefPtr<UtilityProcessManager> utilityProc =
+      UtilityProcessManager::GetSingleton();
+  MOZ_ASSERT(utilityProc, "No UtilityprocessManager?");
+
+  for (RefPtr<UtilityProcessParent>& parent :
+       utilityProc->GetAllProcessesProcessParent()) {
+    Unused << parent->SendTestTelemetryProbes();
+  }
+
+  return NS_OK;
+}
+
 NS_IMPL_ISUPPORTS(UtilityProcessTest, nsIUtilityProcessTest)
 
 }  // namespace mozilla::ipc

ipc/glue/test/utility_process_xpcom/nsIUtilityProcessTest.idl

@@ -22,4 +22,11 @@ interface nsIUtilityProcessTest : nsISupports
    * Allowing to stop Utility Process from JS code.
    */
   void stopProcess();
+
+  /**
+   * ** Test-only Method **
+   *
+   * Sending Telemetry probes
+   */
+  void testTelemetryProbes();
 };

toolkit/components/telemetry/Scalars.yaml

@@ -8284,6 +8284,21 @@ telemetry.test:
     record_in_processes:
       - 'socket'
 
+  utility_only_uint:
+    bug_numbers:
+      - 1794409
+    description: A testing uint scalar; not meant to be touched.
+    expires: never
+    kind: uint
+    notification_emails:
+      - telemetry-client-dev@mozilla.com
+    products:
+      - 'firefox'
+      - 'fennec'
+      - 'thunderbird'
+    record_in_processes:
+      - 'utility'
+
   all_processes_uint:
     bug_numbers:
       - 1278556

toolkit/components/telemetry/tests/unit/test_UtilityScalars.js

@@ -0,0 +1,65 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/
+*/
+
+const { TelemetryController } = ChromeUtils.import(
+  "resource://gre/modules/TelemetryController.jsm"
+);
+const { ContentTaskUtils } = ChromeUtils.import(
+  "resource://testing-common/ContentTaskUtils.jsm"
+);
+
+const UTILITY_ONLY_UINT_SCALAR = "telemetry.test.utility_only_uint";
+
+const utilityProcessTest = () => {
+  return Cc["@mozilla.org/utility-process-test;1"].createInstance(
+    Ci.nsIUtilityProcessTest
+  );
+};
+
+/**
+ * This function waits until utility scalars are reported into the
+ * scalar snapshot.
+ */
+async function waitForUtilityScalars() {
+  await ContentTaskUtils.waitForCondition(() => {
+    const scalars = Telemetry.getSnapshotForScalars("main", false);
+    return Object.keys(scalars).includes("utility");
+  }, "Waiting for utility scalars to have been set");
+}
+
+async function waitForUtilityValue() {
+  await ContentTaskUtils.waitForCondition(() => {
+    return (
+      UTILITY_ONLY_UINT_SCALAR in
+      Telemetry.getSnapshotForScalars("main", false).utility
+    );
+  }, "Waiting for utility uint value");
+}
+
+add_setup(async function setup_telemetry_utility() {
+  info("Start a UtilityProcess");
+  await utilityProcessTest().startProcess();
+
+  do_get_profile(true);
+  await TelemetryController.testSetup();
+});
+
+add_task(async function test_scalars_in_utility_process() {
+  Telemetry.clearScalars();
+  await utilityProcessTest().testTelemetryProbes();
+
+  // Once scalars are set by the utility process, they don't immediately get
+  // sent to the parent process. Wait for the Telemetry IPC Timer to trigger
+  // and batch send the data back to the parent process.
+  await waitForUtilityScalars();
+  await waitForUtilityValue();
+
+  Assert.equal(
+    Telemetry.getSnapshotForScalars("main", false).utility[
+      UTILITY_ONLY_UINT_SCALAR
+    ],
+    42,
+    `${UTILITY_ONLY_UINT_SCALAR} must have the correct value (utility process).`
+  );
+});

toolkit/components/telemetry/tests/unit/xpcshell.ini

@@ -115,5 +115,6 @@ tags = coverage
 [test_bug1555798.js]
 [test_UninstallPing.js]
 run-if = os == "win"
+[test_UtilityScalars.js]
 [test_failover_retry.js]
 skip-if = os == "android" # Android doesn't support telemetry though some tests manage to pass with xpcshell