/** * Copyright (c) Facebook, Inc. and its affiliates. * * This source code is licensed under the MIT license found in the * LICENSE file in the root directory of this source tree. * * @format * @emails oncall+react_native */ 'use strict'; describe('warnOnce', () => { const warnOnce = require('../warnOnce'); it('logs warning messages to the console exactly once', () => { jest.spyOn(console, 'warn').mockReturnValue(undefined); warnOnce('test-message', 'This is a log message'); warnOnce('test-message', 'This is a second log message'); expect(console.warn).toHaveBeenCalledWith('This is a log message'); expect(console.warn).toHaveBeenCalledTimes(1); console.warn.mockRestore(); }); });