1 files changed, 44 insertions, 0 deletions
diff --git a/toolkit/components/webextensions/test/xpcshell/test_ext_alarms_replaces.js b/toolkit/components/webextensions/test/xpcshell/test_ext_alarms_replaces.js
new file mode 100644
index 000000000..96f61acb5
--- /dev/null
+++ b/toolkit/components/webextensions/test/xpcshell/test_ext_alarms_replaces.js
@@ -0,0 +1,44 @@
+/* -*- Mode: indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set sts=2 sw=2 et tw=80: */
+"use strict";
+
+
+add_task(function* test_duplicate_alarm_name_replaces_alarm() {
+  function backgroundScript() {
+    let count = 0;
+
+    browser.alarms.onAlarm.addListener(async alarm => {
+      if (alarm.name === "master alarm") {
+        browser.alarms.create("child alarm", {delayInMinutes: 0.05});
+        let results = await browser.alarms.getAll();
+
+        browser.test.assertEq(2, results.length, "exactly two alarms exist");
+        browser.test.assertEq("master alarm", results[0].name, "first alarm has the expected name");
+        browser.test.assertEq("child alarm", results[1].name, "second alarm has the expected name");
+
+        if (count++ === 3) {
+          await browser.alarms.clear("master alarm");
+          await browser.alarms.clear("child alarm");
+
+          browser.test.notifyPass("alarm-duplicate");
+        }
+      } else {
+        browser.test.fail("duplicate named alarm replaced existing alarm");
+        browser.test.notifyFail("alarm-duplicate");
+      }
+    });
+
+    browser.alarms.create("master alarm", {delayInMinutes: 0.025, periodInMinutes: 0.025});
+  }
+
+  let extension = ExtensionTestUtils.loadExtension({
+    background: `(${backgroundScript})()`,
+    manifest: {
+      permissions: ["alarms"],
+    },
+  });
+
+  yield extension.startup();
+  yield extension.awaitFinish("alarm-duplicate");
+  yield extension.unload();
+});