1 files changed, 51 insertions, 0 deletions
diff --git a/toolkit/components/glean/tests/xpcshell/test_FOGIPCLimit.js b/toolkit/components/glean/tests/xpcshell/test_FOGIPCLimit.js
new file mode 100644
index 0000000000..10ab9f5bc3
--- /dev/null
+++ b/toolkit/components/glean/tests/xpcshell/test_FOGIPCLimit.js
@@ -0,0 +1,51 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const { AppConstants } = ChromeUtils.importESModule(
+  "resource://gre/modules/AppConstants.sys.mjs"
+);
+
+const { ContentTaskUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/ContentTaskUtils.sys.mjs"
+);
+
+add_setup(
+  /* on Android FOG is set up through head.js */
+  { skip_if: () => !runningInParent || AppConstants.platform == "android" },
+  function test_setup() {
+    // Give FOG a temp profile to init within.
+    do_get_profile();
+
+    // We need to initialize it once, otherwise operations will be stuck in the pre-init queue.
+    Services.fog.initializeFOG();
+  }
+);
+
+// Keep in sync with ipc.rs.
+// "Why no -1?" Because the limit's 100k. The -1 is because of atomic ops.
+const FOG_IPC_PAYLOAD_ACCESS_LIMIT = 100000;
+
+add_task({ skip_if: () => runningInParent }, async function run_child_stuff() {
+  for (let i = 0; i < FOG_IPC_PAYLOAD_ACCESS_LIMIT + 1; i++) {
+    Glean.testOnly.badCode.add(1);
+  }
+});
+
+add_task(
+  { skip_if: () => !runningInParent },
+  async function test_fog_ipc_limit() {
+    await run_test_in_child("test_FOGIPCLimit.js");
+
+    await ContentTaskUtils.waitForCondition(() => {
+      return !!Glean.testOnly.badCode.testGetValue();
+    }, "Waiting for IPC.");
+
+    // The child exceeded the number of accesses to trigger an IPC flush.
+    Assert.greater(
+      Glean.testOnly.badCode.testGetValue(),
+      FOG_IPC_PAYLOAD_ACCESS_LIMIT
+    );
+  }
+);