checkWatchmanCapabilities-test.js

/**
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @format
 * @flow strict
 */

import checkWatchmanCapabilities from '../checkWatchmanCapabilities';

const mockExecFile = jest.fn();
jest.mock('child_process', () => ({
  execFile: (...args) => mockExecFile(...args),
}));

const mockSuccessResponse = JSON.stringify({
  version: 'v123',
  capabilities: ['c1', 'c2'],
});

function setMockExecFileResponse(err: mixed, stdout?: mixed) {
  mockExecFile.mockImplementation((file, args, cb) => {
    expect(file).toBe('watchman');
    cb(err, err == null ? {stdout} : null);
  });
}

describe('checkWatchmanCapabilities', () => {
  beforeEach(() => {
    jest.clearAllMocks();
  });

  it('executes watchman list-capabilities and resolves on success', async () => {
    setMockExecFileResponse(null, mockSuccessResponse);
    await expect(checkWatchmanCapabilities(['c1', 'c2'])).resolves.toEqual();
    expect(mockExecFile).toHaveBeenCalledWith(
      'watchman',
      [
        'list-capabilities',
        '--output-encoding=json',
        '--no-pretty',
        '--no-spawn',
      ],
      expect.any(Function),
    );
  });

  it('rejects when execFile reports ENOENT', async () => {
    setMockExecFileResponse({code: 'ENOENT'});
    await expect(checkWatchmanCapabilities([])).rejects.toMatchInlineSnapshot(
      `[Error: Watchman is not installed or not available on PATH]`,
    );
    expect(mockExecFile).toHaveBeenCalled();
  });

  it('rejects when execFile fails', async () => {
    setMockExecFileResponse(new Error('execFile error'));
    await expect(checkWatchmanCapabilities([])).rejects.toMatchInlineSnapshot(
      `[Error: execFile error]`,
    );
    expect(mockExecFile).toHaveBeenCalled();
  });

  it('rejects when the response is not JSON', async () => {
    setMockExecFileResponse(null, 'not json');
    await expect(checkWatchmanCapabilities([])).rejects.toMatchInlineSnapshot(
      `[Error: Failed to parse response from \`watchman list-capabilities\`]`,
    );
    expect(mockExecFile).toHaveBeenCalled();
  });

  it('rejects when we are missing a required capability', async () => {
    setMockExecFileResponse(null, mockSuccessResponse);
    await expect(
      checkWatchmanCapabilities(['c1', 'other-cap']),
    ).rejects.toMatchInlineSnapshot(
      `[Error: The installed version of Watchman (v123) is missing required capabilities: other-cap]`,
    );
    expect(mockExecFile).toHaveBeenCalled();
  });
});