1 files changed, 23 insertions, 0 deletions
diff --git a/toolkit/components/backgroundhangmonitor/tests/child_cause_hang.js b/toolkit/components/backgroundhangmonitor/tests/child_cause_hang.js
new file mode 100644
index 0000000000..adf96170b6
--- /dev/null
+++ b/toolkit/components/backgroundhangmonitor/tests/child_cause_hang.js
@@ -0,0 +1,23 @@
+/* Any copyright is dedicated to the Public Domain.
+ http://creativecommons.org/publicdomain/zero/1.0/ */
+
+function ensureProfilerInitialized() {
+  // Starting and stopping the profiler with the "stackwalk" flag will cause the
+  // profiler's stackwalking features to be synchronously initialized. This
+  // should prevent us from not initializing BHR quickly enough.
+  let features = ["stackwalk"];
+  Services.profiler.StartProfiler(1000, 10, features);
+  Services.profiler.StopProfiler();
+}
+
+add_task(async function childCauseHang() {
+  ensureProfilerInitialized();
+
+  executeSoon(() => {
+    let startTime = Date.now();
+    // eslint-disable-next-line no-empty
+    while (Date.now() - startTime < 2000) {}
+  });
+
+  await do_await_remote_message("bhr_hangs_detected");
+});