Bug 1828178 - Profiler tests should not fail when MOZ_PROFILER_STARTUP is set...

Bug 1828178 - Profiler tests should not fail when MOZ_PROFILER_STARTUP is set in the environment, r=canaltinova.

Differential Revision: https://phabricator.services.mozilla.com/D175512

ipc/glue/test/browser/browser_utility_profiler.js

@@ -20,7 +20,7 @@ add_task(async () => {
   const utilityPid = await startUtilityProcess();
 
   info("Start the profiler");
-  startProfiler();
+  await startProfiler();
 
   let profile;
   await TestUtils.waitForCondition(async () => {

tools/profiler/tests/browser/browser_test_feature_ipcmessages.js

@@ -24,11 +24,6 @@ async function waitForLoad() {
  * Test the IPCMessages feature.
  */
 add_task(async function test_profile_feature_ipcmessges() {
-  Assert.ok(
-    !Services.profiler.IsActive(),
-    "The profiler is not currently active"
-  );
-
   const url = BASE_URL + "simple.html";
 
   info("Open a tab while profiling IPC messages.");

tools/profiler/tests/shared-head.js

@@ -3,6 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 /* globals Assert */
+/* globals info */
 
 /**
  * This file contains utilities that can be shared between xpcshell tests and mochitests.
@@ -27,11 +28,28 @@ const defaultSettings = {
 // Effectively `async`: Start the profiler and return the `startProfiler`
 // promise that will get resolved when all child process have started their own
 // profiler.
-function startProfiler(callersSettings) {
+async function startProfiler(callersSettings) {
   if (Services.profiler.IsActive()) {
-    throw new Error(
-      "The profiler must not be active before starting it in a test."
+    Assert.ok(
+      Services.env.exists("MOZ_PROFILER_STARTUP"),
+      "The profiler is active at the begining of the test, " +
+        "the MOZ_PROFILER_STARTUP environment variable should be set."
     );
+    if (Services.env.exists("MOZ_PROFILER_STARTUP")) {
+      // If the startup profiling environment variable exists, it is likely
+      // that tests are being profiled.
+      // Stop the profiler before starting profiler tests.
+      info(
+        "This test starts and stops the profiler and is not compatible " +
+          "with the use of MOZ_PROFILER_STARTUP. " +
+          "Stopping the profiler before starting the test."
+      );
+      await Services.profiler.StopProfiler();
+    } else {
+      throw new Error(
+        "The profiler must not be active before starting it in a test."
+      );
+    }
   }
   const settings = Object.assign({}, defaultSettings, callersSettings);
   return Services.profiler.StartProfiler(