Wrong lines are shown in Jest output (for errors or failed expectations)0

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

Bug?

What is the current behavior?

Line numbers for errors or failed expectations are wrong.

reproduction

Reproduction: https://github.com/trusktr/lowclass/tree/jest-issue-5942

Check out that branch, then to see the error run

npm i
npm test

Note, npm test runs Jest with builder,

To run the Jest test manually (for ease in debugging), you can run this command:

❯ node --inspect-brk ./node_modules/.bin/jest --config ./node_modules/builder-js-package/config/jest.config.js

The failed expectation is on line 886 of src/test.js but Jest reports a line of 896 and shows the wrong part of the code in the output.

What is the expected behavior?

I am expecting to see something like

    expect(received).toBe(expected) // Object.is equality

    Expected value to be:
      true
    Received:
      undefined

    Difference:

      Comparing two different types of values. Expected boolean but received undefined.

      884 |        // provide a hint on how we can make it work (traverse towards leaf of
      885 |        // the private prototype chain and find the instance)
    > 886 |        expect( b.testedFail ).toBe( true )
      887 |
      888 |        // native `super` works too:
      889 |        const Baz = Class().extends(Bar, ({Super}) => ({

      at Object.<anonymous>.test (src/test.js:886:30)

but instead I am seeing

    expect(received).toBe(expected) // Object.is equality

    Expected value to be:
      true
    Received:
      undefined

    Difference:

      Comparing two different types of values. Expected boolean but received undefined.

      894 |             }
      895 |         }))
    > 896 |
      897 |         const baz = new Baz
      898 |         baz.test()
      899 |         baz.testFail()

      at Object.<anonymous>.test (src/test.js:896:30)

Please provide your exact Jest configuration

module.exports = {
    rootDir: process.cwd(),

    transform: {
        '^.+\\.js$': path.resolve(__dirname, 'babel-jest'),
    },

    // a great environment that supports Custom Elements
    testEnvironment: '@skatejs/ssr/jest',
}

where the sibling babel-jest.js file contains

const CWD = process.cwd()

const babelJest = require('babel-jest')

module.exports = babelJest.createTransformer({
    presets: [
        ['env', {
            targets: {
                node: 6,
            },
        }],
    ],
})

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

❯ npx envinfo --preset jest
npx: installed 1 in 2.41s

  System:
    OS: Linux 3.18
    CPU: x64 Intel(R) Core(TM) m3-6Y30 CPU @ 0.90GHz
  Binaries:
    Node: 9.9.0
    Yarn: 1.3.2
    npm: 5.8.0

❯ cat node_modules/jest/package.json | grep version
  "version": "22.4.3"

Jest is not installed globally

[ChenRoth]

happens to me with jest 23.4.1 and ts-jest 23.0.1

[Cielquan]

I came across this issue as I was having the same problem and in my case I could track it down to multiline docstrings.

Working example

I have a helper function and added a docstring to it. The single line variant does work as expected.

/** Single line docstring */
const helper = (): number => 2;

describe("test case", () => {
  it("shows wrong line number on error", () => {
    const result = 1 + helper();

    expect(result).toBe(4);
  });
});

export {};

$ yarn test-jest-ci __tests__/issue5942Repro.test.ts 
 FAIL  __tests__/issue5942Repro.test.ts
  test case
    × shows wrong line number on error (3 ms)

  ● test case › shows wrong line number on error

    expect(received).toBe(expected) // Object.is equality

    Expected: 4
    Received: 3

       6 |     const result = 1 + helper();
       7 |
    >  8 |     expect(result).toBe(4);
         |                    ^
       9 |   });
      10 | });
      11 |

      at Object.<anonymous> (__tests__/issue5942Repro.test.ts:8:20)

Broken example

When I change the docstring to be multiline, the issue occurs.

/** Multiline docstring
 */
const helper = (): number => 2;

describe("test case", () => {
  it("shows wrong line number on error", () => {
    const result = 1 + helper();

    expect(result).toBe(4);
  });
});

export {};

$ yarn test-jest-ci __tests__/issue5942Repro.test.ts 
 FAIL  __tests__/issue5942Repro.test.ts
  test case
    × shows wrong line number on error (3 ms)

  ● test case › shows wrong line number on error

    expect(received).toBe(expected) // Object.is equality

    Expected: 4
    Received: 3

       8 |
       9 |     expect(result).toBe(4);
    > 10 |   });
         |   ^
      11 | });
      12 |
      13 | export {};

      at Object.<anonymous> (__tests__/issue5942Repro.test.ts:10:3)

Additional Information

I have a typescript nextJS v13 project and created the above test case in it.

The run script is this: "test-jest-ci": "jest --ci", and I cut the coverage report off.

$ npx envinfo --preset jest

  System:
    OS: Windows 10 10.0.19042
    CPU: (12) x64 12th Gen Intel(R) Core(TM) i7-1265U
  Binaries:
    Node: 18.12.1 - C:\Program Files\nodejs\node.EXE 
    Yarn: 3.2.1 - ~\AppData\Roaming\npm\yarn.CMD     
    npm: 8.19.2 - C:\Program Files\nodejs\npm.CMD

$ cat node_modules/jest/package.json | grep version
  "version": "29.3.1",

jest.config.ts

import type { Config } from "jest";
import nextJest from "next/jest";

// Sync object
const createNextJestConfig: (customJestConfig?: Config) => () => Promise<Config> = nextJest({
  // Provide the path to your Next.js app to load next.config.js and .env files in your test
  // environment
  dir: "./",
});

// Add any custom config to be passed to Jest
const customJestConfig: Config = {
  // Add more setup options before each test is run
  setupFilesAfterEnv: ["@testing-library/jest-dom"],
  // if using TypeScript with a baseUrl set to
  // the root directory then you need the below for alias' to work
  moduleDirectories: ["../../node_modules", "<rootDir>/"],
  testEnvironment: "jest-environment-jsdom",
  modulePathIgnorePatterns: ["cypress"],
  transformIgnorePatterns: ["/node_modules/(?!jose)/"],
  clearMocks: true,
  resetMocks: true,
  restoreMocks: true,
  collectCoverage: true,
  collectCoverageFrom: ["src/**/*.{ts,tsx}"],
  coverageDirectory: "../../.coverage_cache/swlp_frontend",
  coverageThreshold: {
    global: {
      branches: 100,
      functions: 100,
      lines: 100,
      statements: 100,
    },
  },
};

/** Removes "node_modules" from "transformIgnorePatterns" added by nextJS. */
const removeNodeModulesFromConfig = (jestConfig: Config): Config => {
  if (jestConfig.transformIgnorePatterns === undefined) return jestConfig;
  const idx = jestConfig.transformIgnorePatterns.findIndex((v: string) =>
    v.includes("node_modules"),
  );
  jestConfig.transformIgnorePatterns.splice(idx, 1);

  return jestConfig;
};

const createCustomJestConfig = async (): Promise<Config> => {
  const nextJestConfig = await createNextJestConfig(customJestConfig)();
  return removeNodeModulesFromConfig(nextJestConfig);
};

export default createCustomJestConfig;