ui/src/base/events_unittest.ts

// Copyright (C) 2023 The Android Open Source Project
//
// 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 {defer} from './deferred';
import {DisposableStack} from './disposable_stack';
import {EvtSource} from './events';

describe('Events', () => {
  test('voidEvent', () => {
    const ev = new EvtSource<void>();
    const calls: string[] = [];
    ev.addListener(() => calls.push('listener1'));
    ev.addListener(() => calls.push('listener2'));
    ev.notify();
    expect(calls).toEqual(['listener1', 'listener2']);
    ev.notify();
    expect(calls).toEqual(['listener1', 'listener2', 'listener1', 'listener2']);
  });

  test('eventWithArgs', () => {
    const ev = new EvtSource<number>();
    const argsReceived = new Array<number>();
    ev.addListener((n: number) => argsReceived.push(n));
    ev.notify(1);
    ev.notify(2);
    expect(argsReceived).toEqual([1, 2]);
  });

  test('asyncEvent', async () => {
    const ev = new EvtSource<number>();
    const argsReceived = new Array<number>();
    ev.addListener((n: number) => {
      const promise = defer<void>();
      setTimeout(() => {
        argsReceived.push(n);
        promise.resolve();
      }, 0);
      return promise;
    });
    await ev.notify(1);
    await ev.notify(2);
    await ev.notify(3);
    expect(argsReceived).toEqual([1, 2, 3]);
  });

  test('dispose', () => {
    const ev = new EvtSource<void>();
    const calls: string[] = [];
    const trash = new DisposableStack();
    trash.use(ev.addListener(() => calls.push('listener1')));
    trash.use(ev.addListener(() => calls.push('listener2')));
    ev.notify();
    expect(calls).toEqual(['listener1', 'listener2']);
    calls.splice(0);

    trash.dispose();
    ev.notify();
    expect(calls).toEqual([]);

    trash.use(ev.addListener(() => calls.push('listener3')));
    ev.notify();
    expect(calls).toEqual(['listener3']);
  });
});