1 files changed, 72 insertions, 0 deletions
diff --git a/devtools/shared/test-helpers/test_javascript_tracer.js b/devtools/shared/test-helpers/test_javascript_tracer.js
new file mode 100644
index 0000000000..268e054c56
--- /dev/null
+++ b/devtools/shared/test-helpers/test_javascript_tracer.js
@@ -0,0 +1,72 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/**
+ * Test for the thread helpers utility module.
+ *
+ * This uses a xpcshell test in order to avoid recording the noise
+ * of all Firefox components when using a mochitest.
+ */
+
+const { traceAllJSCalls } = ChromeUtils.importESModule(
+  "resource://devtools/shared/test-helpers/thread-helpers.sys.mjs"
+);
+// ESLint thinks this is a browser test, but it's actually an xpcshell
+// test and so `setTimeout` isn't available out of the box.
+// eslint-disable-next-line mozilla/no-redeclare-with-import-autofix
+const { setTimeout } = ChromeUtils.importESModule(
+  "resource://gre/modules/Timer.sys.mjs"
+);
+
+add_task(async function sanityCheck() {
+  let ranTheOtherEventLoop = false;
+  setTimeout(function otherEventLoop() {
+    ranTheOtherEventLoop = true;
+  }, 0);
+  const jsTracer = traceAllJSCalls();
+  function foo() {}
+  for (let i = 0; i < 10; i++) {
+    foo();
+  }
+  jsTracer.stop();
+  ok(
+    !ranTheOtherEventLoop,
+    "When we don't pause frame execution, the other event do not execute"
+  );
+});
+
+add_task(async function withPrefix() {
+  const jsTracer = traceAllJSCalls({ prefix: "my-prefix" });
+  function foo() {}
+  for (let i = 0; i < 10; i++) {
+    foo();
+  }
+  jsTracer.stop();
+  ok(true, "Were able to run with a prefix argument");
+});
+
+add_task(async function pause() {
+  const start = Cu.now();
+  let ranTheOtherEventLoop = false;
+  setTimeout(function otherEventLoop() {
+    ranTheOtherEventLoop = true;
+  }, 0);
+  const jsTracer = traceAllJSCalls({ pause: 100 });
+  function foo() {}
+  for (let i = 0; i < 10; i++) {
+    foo();
+  }
+  jsTracer.stop();
+  const duration = Cu.now() - start;
+  Assert.greater(
+    duration,
+    10 * 100,
+    "The execution of the for loop was slow down by at least the pause duration in each loop"
+  );
+  ok(
+    ranTheOtherEventLoop,
+    "When we pause frame execution, the other event can execute"
+  );
+});