1 files changed, 65 insertions, 0 deletions
diff --git a/toolkit/components/telemetry/tests/unit/test_UtilityScalars.js b/toolkit/components/telemetry/tests/unit/test_UtilityScalars.js
new file mode 100644
index 0000000000..b6c0842910
--- /dev/null
+++ b/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.importESModule(
+  "resource://gre/modules/TelemetryController.sys.mjs"
+);
+const { ContentTaskUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/ContentTaskUtils.sys.mjs"
+);
+
+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).`
+  );
+});