Make a passing `.toThrow()` not dump to `console.error`

Do you want to request a feature or report a bug?

Feature

What is the current behavior?

Writing a test for an exception still dumps that exception to the output, which is very confusing: It took me a while to realize that buried after screen and screens of red stack traces, my tests were showing as PASS…

I don’t want to use --silent during development, as I’d use the ability to quickly console.log the shape of objects I’m trying to expect, etc…

As a work-around, I’m creating a spy on console.error, but that of course also swallows and exceptions that I’m not yet testing for:

beforeAll(() => {
  jest.spyOn(console, 'error').mockImplementation(() => undefined);
});

afterAll(() => {
  console.error.mockRestore();
});

What is the expected behavior?

It would be great if exceptions happening inside .toThrow would not get dumped to console IF they PASS the assertion. (I guess that would take some kind of buffering of the output?)

Please provide your exact Jest configuration

const path = require('path');

const isCI = process.argv.includes('--ci');

module.exports = {
  rootDir: '../packages',
  testMatch: ['**/__tests__/*.{js,jsx}', '**/*.{spec,test}?(s).{js,jsx}'],

  collectCoverage: isCI,
  collectCoverageFrom: [
    '**/src/**?(/)*.{js,jsx}',
    // ignore:
    '!**/__stories__/**',
    '!**/*.stories.{js,jsx}',
  ],
  coverageDirectory: path.resolve(__dirname, '..', 'coverage'),
  coverageThreshold: isCI
    ? {
        global: {
          branches: 100,
          functions: 100,
          lines: 100,
          statements: 0,
        },
      }
    : undefined,
};

Run npx envinfo --preset jest in your project directory and paste the results here

  System:
    OS: macOS High Sierra 10.13.3
    CPU: x64 Intel(R) Core(TM) i7-4850HQ CPU @ 2.30GHz
  Binaries:
    Node: 8.8.1
    Yarn: 1.5.1
    npm: 5.4.2
  npmPackages:
    jest:
      wanted: ^22.4.2
      installed: 22.4.2

[davidgilbertson]

I’m doing this, thanks @kevinbarabash for the link.

export const expectToThrow = func => {
  // Even though the error is caught, it still gets printed to the console
  // so we mock that out to avoid the wall of red text.
  jest.spyOn(console, 'error');
  console.error.mockImplementation(() => {});

  expect(func).toThrow();

  console.error.mockRestore();
};

[kevinbarabash]

I’m experiencing this when using enzyme’s mount() to render a component that throws in its render() function. I’m guess it has something to do with the way that jsdom’s error handling works.