1// Copyright (C) 2024 The Android Open Source Project 2// 3// Licensed under the Apache License, Version 2.0 (the "License"); 4// you may not use this file except in compliance with the License. 5// You may obtain a copy of the License at 6// 7// http://www.apache.org/licenses/LICENSE-2.0 8// 9// Unless required by applicable law or agreed to in writing, software 10// distributed under the License is distributed on an "AS IS" BASIS, 11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12// See the License for the specific language governing permissions and 13// limitations under the License. 14 15import {Monitor} from './monitor'; 16 17test('callback is called when state changes', () => { 18 const reducer = jest.fn().mockReturnValue('foo'); 19 const monitor = new Monitor([reducer]); 20 const mockCallback = jest.fn(); 21 22 monitor.ifStateChanged(mockCallback); 23 expect(mockCallback).toHaveBeenCalledTimes(1); 24 25 mockCallback.mockReset(); 26 monitor.ifStateChanged(mockCallback); 27 monitor.ifStateChanged(mockCallback); 28 expect(mockCallback).not.toHaveBeenCalled(); 29 30 mockCallback.mockReset(); 31 reducer.mockReturnValue('bar'); 32 monitor.ifStateChanged(mockCallback); 33 expect(mockCallback).toHaveBeenCalledTimes(1); 34 35 mockCallback.mockReset(); 36 monitor.ifStateChanged(mockCallback); 37 expect(mockCallback).not.toHaveBeenCalled(); 38}); 39