toMatchInlineSnapshot fails if prettier's native module deps are mocked through jest.mock

🐛 Bug Report

toMatchInlineSnapshot fails if path module is mocked

jest.mock('path', () => ({}));

test('foo', () => {
  expect({}).toMatchInlineSnapshot();
});

results in

● Test suite failed to run

    TypeError: path.resolve is not a function

Run npx envinfo --preset jest

Paste the results here:

  System:
    OS: macOS High Sierra 10.13.5
    CPU: x64 Intel(R) Core(TM) i7-6567U CPU @ 3.30GHz
  Binaries:
    Node: 8.9.4 - ~/.nvm/versions/node/v8.9.4/bin/node
    Yarn: 1.7.0 - /usr/local/bin/yarn
    npm: 5.6.0 - ~/.nvm/versions/node/v8.9.4/bin/npm
  npmPackages:
    jest: ^23.4.0 => 23.4.0

[tryggvigy]

Thanks for explaining @aaronabramov! Also, unfortunately yes I can reproduce this on master.

Here is the test I added to e2e/__tests__/to_match_inline_snapshot.test.js and reproduces the bug on latest master.

test('fails', () => {
  const filename = 'mockFail.test.js';
  const test = `
    jest.mock('path', () => ({}));
    test('hæhæ!', () => {
      expect({}).toMatchInlineSnapshot();
    });
  `;

  writeFiles(TESTS_DIR, {[filename]: test});
  const {stderr, status} = runJest(DIR, ['-w=1', '--ci=false', filename]);
  expect(stderr).toMatch('1 snapshot written from 1 test suite.');
  expect(status).toBe(0);
});

[tryggvigy]

I’m trying to dig into this. I’ve got a test that reproduces the bug in e2e/__tests__/to_match_inline_snapshot.test.js.

The error is coming from the compiled node_modules/prettier/third-party.js and originally from this line in cosmiconfig dependency. Thats the code thats trying to run when TypeError: path.resolve is not a function happens.

---

node_modules/prettier/prettier-bin.js is right now using these native modules

var path = _interopDefault(require('path'));
var os = _interopDefault(require('os'));
var assert = _interopDefault(require('assert'));
var fs = _interopDefault(require('fs'));
var util = _interopDefault(require('util'));
var events = _interopDefault(require('events'));
var thirdParty = require('./third-party');
var thirdParty__default = thirdParty['default'];
var readline = _interopDefault(require('readline'));
// and these two through ./third-party
var stream = _interopDefault(require('stream'));
var module$1 = _interopDefault(require('module'));

I’m assuming jest.mock will overrider any of the above. I’m unsure how to actually fix this issue (looking at https://github.com/facebook/jest/pull/6687 for inspiration) but I’ll keep digging. I’d appreciate any input from folks with more context.

update jest.mock only causes failure on some of them

mock path -- TypeError: path.resolve is not a function
mock fs -- TypeError: fs.statSync is not a function
mock os -- TypeError: os.homedir is not a function
mock assert -- TypeError: assert is not a function
mock utils -- passes
mock readline -- passes
mock stream -- passes
mock module -- passes