concat_stream_providers.test.ts

/*
 * Licensed to Elasticsearch B.V. under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch B.V. licenses this file to you 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 { Readable } from 'stream';

import { concatStreamProviders } from './concat_stream_providers';
import { createListStream } from './list_stream';
import { createConcatStream } from './concat_stream';
import { createPromiseFromStreams } from './promise_from_streams';

describe('concatStreamProviders() helper', () => {
  test('writes the data from an array of stream providers into a destination stream in order', async () => {
    const results = await createPromiseFromStreams([
      concatStreamProviders([
        () => createListStream(['foo', 'bar']),
        () => createListStream(['baz']),
        () => createListStream(['bug']),
      ]),
      createConcatStream(''),
    ]);

    expect(results).toBe('foobarbazbug');
  });

  test('emits the errors from a sub-stream to the destination', async () => {
    const dest = concatStreamProviders([
      () => createListStream(['foo', 'bar']),
      () =>
        new Readable({
          read() {
            this.destroy(new Error('foo'));
          },
        }),
    ]);

    const errorListener = jest.fn();
    dest.on('error', errorListener);

    await expect(createPromiseFromStreams([dest])).rejects.toThrowErrorMatchingInlineSnapshot(
      `"foo"`
    );
    expect(errorListener.mock.calls).toMatchInlineSnapshot(`
Array [
  Array [
    [Error: foo],
  ],
]
`);
  });
});