web/test/test-util.ts

// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

/**
 * Asserts that the given promise will rejected.
 *
 * @param promise The Promise that is expected to reject.
 * @param expectedReason Expected rejection reason.
 *   If RegExp or string, then rejection reason is expected to have message
 *   property (like Error) that matches the expected reason.
 */
export async function assertRejects(promise: any, expectedReason: any = null) {
  try {
    await promise;
    assert.fail('exception', 'no exception');
  } catch (actualReason: unknown) {
    if (expectedReason) {
      if (expectedReason instanceof RegExp) {
        assert.match((actualReason as Error).message, expectedReason);
      } else if (typeof expectedReason === 'string') {
        assert.equal((actualReason as Error).message, expectedReason);
      } else {
        assert.deepEqual(actualReason, expectedReason);
      }
    }
  }
}

export function deepFreeze(obj: any) {
  for (const p of Object.keys(obj)) {
    const v = obj[p];
    if (typeof v === 'object' && v !== null) {
      deepFreeze(v);
    }
  }
  return Object.freeze(obj);
}