third_party/perfetto/ui/src/base/deferred_unittest.ts

// Copyright (C) 2018 The Android Open Source Project
//
// 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 {defer, Deferred} from './deferred';

test('deferred can resolve', async () => {
  const deferred: Deferred<void> = defer<void>();
  let i = 0;
  deferred.then(() => i++);

  expect(i).toBe(0);
  deferred.resolve();
  expect(i).toBe(0);
  await deferred;
  expect(i).toBe(1);
});

test('deferred can resolve with value', () => {
  const deferred: Deferred<string> = defer<string>();
  deferred.resolve('foo');
  return expect(deferred).resolves.toBe('foo');
});

test('deferred can reject', () => {
  const deferred: Deferred<string> = defer<string>();
  deferred.reject('foo');
  return expect(deferred).rejects.toBe('foo');
});