MOBILE-4069 test: Add unit tests to CoreEvents singleton

src/core/singletons/events.ts

@@ -192,8 +192,7 @@ export class CoreEvents {
         siteId?: string,
     ): CoreEventObserver {
         const listener = CoreEvents.on<Fallback, Event>(eventName, (value) => {
-            setTimeout(() => listener.off(), 0);
-
+            listener.off();
             callBack(value);
         }, siteId);
 
@@ -241,7 +240,7 @@ export class CoreEvents {
             if (siteId) {
                 Object.assign(data || {}, { siteId });
             }
-            this.observables[eventName].next(data);
+            this.observables[eventName].next(data || {});
         }
     }
 

src/core/singletons/tests/events.test.ts

@@ -0,0 +1,110 @@
+// (C) Copyright 2015 Moodle Pty Ltd.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import { CoreEvents } from '@singletons/events';
+
+const eventName = 'my-event';
+
+describe('CoreEvents singleton', () => {
+
+    it('can be used to trigger and receive events', () => {
+        const callback = jest.fn();
+        const secondCallback = jest.fn();
+        const data = { foo: 'bar' };
+
+        const listener = CoreEvents.on(eventName, callback);
+        CoreEvents.on('another-event', secondCallback);
+
+        CoreEvents.trigger(eventName, data);
+
+        expect(callback).toHaveBeenCalledWith(data);
+        expect(callback).toHaveBeenCalledTimes(1);
+        expect(secondCallback).not.toHaveBeenCalled();
+
+        listener.off();
+        CoreEvents.trigger(eventName, data);
+        expect(callback).toHaveBeenCalledTimes(1);
+    });
+
+    it('only calls the right listeners based on site ID', () => {
+        const callback = jest.fn();
+        const secondCallback = jest.fn();
+        const thirdCallback = jest.fn();
+        const siteId = 'site-id';
+        const data = { foo: 'bar' };
+        const dataWithSiteId = {
+            ...data,
+            siteId,
+        };
+
+        CoreEvents.on(eventName, callback);
+        CoreEvents.on(eventName, secondCallback, siteId);
+        CoreEvents.on(eventName, thirdCallback, 'another-site-id');
+
+        CoreEvents.trigger(eventName, data, siteId);
+
+        expect(callback).toHaveBeenCalledWith(dataWithSiteId);
+        expect(secondCallback).toHaveBeenCalledWith(dataWithSiteId);
+        expect(thirdCallback).not.toHaveBeenCalled();
+    });
+
+    it('can call a listener only once', async () => {
+        const callback = jest.fn();
+
+        CoreEvents.once(eventName, callback);
+        CoreEvents.trigger(eventName);
+
+        expect(callback).toHaveBeenCalledTimes(1);
+
+        CoreEvents.trigger(eventName);
+        expect(callback).toHaveBeenCalledTimes(1);
+    });
+
+    it('can trigger a unique event', async () => {
+        const callback = jest.fn();
+        const secondCallback = jest.fn();
+
+        CoreEvents.on(eventName, callback);
+
+        CoreEvents.triggerUnique(eventName, {});
+        expect(callback).toHaveBeenCalledTimes(1);
+
+        CoreEvents.on(eventName, secondCallback);
+        expect(secondCallback).toHaveBeenCalledTimes(1);
+
+        CoreEvents.triggerUnique(eventName, {});
+        expect(callback).toHaveBeenCalledTimes(1);
+        expect(secondCallback).toHaveBeenCalledTimes(1);
+    });
+
+    it('allows listening to multiple events with a single call', async () => {
+        const callback = jest.fn();
+        const secondEventName = 'second-event';
+
+        const listener = CoreEvents.onMultiple([eventName, secondEventName], callback);
+
+        CoreEvents.trigger(eventName);
+        expect(callback).toHaveBeenCalledTimes(1);
+
+        CoreEvents.trigger(secondEventName);
+        expect(callback).toHaveBeenCalledTimes(2);
+
+        listener.off();
+
+        CoreEvents.trigger(eventName);
+        CoreEvents.trigger(secondEventName);
+        expect(callback).toHaveBeenCalledTimes(2);
+    });
+
+});