material-motion-testing-utils/src/useMockedPerformance.ts

Utilities for testing the Material Motion framework

/** @license
 *  Copyright 2016 - present The Material Motion Authors. All Rights Reserved.
 *
 *  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 {
  after,
  before,
} from 'mocha-sugar-free';

import {
  SinonStub,
  stub,
} from 'sinon';

import {
  Performance,
} from './Performance';

export type PerformanceClosure = (performance: Performance) => any;

/**
 * Replaces window.requestAnimationFrame with a mock for the duration of a mocha
 * testing suite.
 */
export default function useMockedPerformance(closure: PerformanceClosure) {
  return () => {
    const mockPerformance = new Performance();

    before(
      () => {
        stub(performance, 'now').callsFake(mockPerformance.now);
      }
    );

    after(
      () => {
        (performance.now as SinonStub).restore(); // tslint:disable-line: no-unbound-method
      }
    );

    return closure(mockPerformance);
  };
};