1 files changed, 36 insertions, 0 deletions
diff --git a/spec/frontend/diffs/utils/queue_events_spec.js b/spec/frontend/diffs/utils/queue_events_spec.js
new file mode 100644
index 00000000000..007748d8b2c
--- /dev/null
+++ b/spec/frontend/diffs/utils/queue_events_spec.js
@@ -0,0 +1,36 @@
+import api from '~/api';
+import { DEFER_DURATION } from '~/diffs/constants';
+import { queueRedisHllEvents } from '~/diffs/utils/queue_events';
+
+jest.mock('~/api', () => ({
+  trackRedisHllUserEvent: jest.fn(),
+}));
+
+describe('diffs events queue', () => {
+  describe('queueRedisHllEvents', () => {
+    it('does not dispatch the event immediately', () => {
+      queueRedisHllEvents(['know_event']);
+      expect(api.trackRedisHllUserEvent).not.toHaveBeenCalled();
+    });
+
+    it('does dispatch the event after the defer duration', () => {
+      queueRedisHllEvents(['know_event']);
+      jest.advanceTimersByTime(DEFER_DURATION + 1);
+      expect(api.trackRedisHllUserEvent).toHaveBeenCalled();
+    });
+
+    it('increase defer duration based on the provided events count', () => {
+      let deferDuration = DEFER_DURATION + 1;
+      const events = ['know_event_a', 'know_event_b', 'know_event_c'];
+      queueRedisHllEvents(events);
+
+      expect(api.trackRedisHllUserEvent).not.toHaveBeenCalled();
+
+      events.forEach((event, index) => {
+        jest.advanceTimersByTime(deferDuration);
+        expect(api.trackRedisHllUserEvent).toHaveBeenLastCalledWith(event);
+        deferDuration *= index + 1;
+      });
+    });
+  });
+});