angular/devtools/projects/protocol/src/lib/priority-aware-message-bus.spec.ts

/**
 * @license
 * Copyright Google LLC All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */

import {MessageBus} from './message-bus';
import {Events, Topic} from './messages';
import {PriorityAwareMessageBus} from './priority-aware-message-bus';

class MockMessageBus extends MessageBus<Events> {
  cbs: any = {};
  override emit(_: Topic, __: any): boolean {
    return true;
  }
  override on(topic: Topic, cb: any): void {
    this.cbs[topic] = cb;
  }
  override once(topic: Topic, cb: any): void {
    this.cbs[topic] = cb;
  }
  override destroy(): void {}
}

describe('PriorityAwareMessageBus', () => {
  it('should emit not throttled requests', () => {
    const timeout: any = (_: any, __: number) => {};
    const bus = new PriorityAwareMessageBus(new MockMessageBus(), timeout);
    expect(bus.emit('handshake')).toBeTrue();
    expect(bus.emit('inspectorStart')).toBeTrue();
  });

  it('should throttle `getLatestComponentExplorerView`', () => {
    let callback: any;
    const timeout: any = (cb: any, _: number) => {
      callback = cb;
    };
    const bus = new PriorityAwareMessageBus(new MockMessageBus(), timeout);
    expect(bus.emit('getLatestComponentExplorerView')).toBeTrue();
    expect(bus.emit('getLatestComponentExplorerView')).toBeFalse();
    expect(bus.emit('getLatestComponentExplorerView')).toBeFalse();
    callback();
    expect(bus.emit('getLatestComponentExplorerView')).toBeTrue();
  });

  it('should not emit `getLatestComponentExplorerView` if blocked by `getNestedProperties`', () => {
    let callback: any;
    const timeout: any = (cb: any, _: number) => {
      callback = cb;
    };
    const mock = new MockMessageBus();
    const bus = new PriorityAwareMessageBus(mock, timeout);
    bus.on('nestedProperties', () => {});
    expect(bus.emit('getNestedProperties')).toBeTrue();
    expect(bus.emit('getLatestComponentExplorerView')).toBeFalse();
    mock.cbs.nestedProperties();
    expect(bus.emit('getLatestComponentExplorerView')).toBeTruthy();
  });
});