Jest freeze on Error when autoMock and collectCoverage are both true

[typehorror]

• Issue

Test freeze on error when jest autoMock and collectCoverage are set to true.

• Expected behavior

Test should display the error and move on to the next test. The same jest settings work on my babel projects.

• Link to a minimal repo that reproduces this issue
  https://github.com/debrice/jest-hang-bug

[typehorror]

A little more info as I'm investigating the bug here. The issue seems to be coming from the jest unmock() feature introduced in jest-cli 0.9.0 which leads me to think it's a hoisting issue (related to the mock() reported in the readme).

[kulshekhar]

@Debrice this does seem like a hoisting issue.

A quick workaround is to configure ts-jest to skip babel

/cc @GeeWee

[typehorror]

You're right @kulshekhar , skiping babel prevents the test from hanging but creates a new error. If I update the test to read (so it breaks on purpose):

jest.unmock("../index");

import foo from "../index";

it("will hang", () => {
  expect(()=>foo("test")).not.toThrow();
})

Running the test with skipBabel set to true gives me that sourceMap.map.originalPositionFor error in its output

$ yarn test
yarn run v1.3.2
$ jest
 FAIL  __tests__/index.ts
  ✕ will hang (24ms)

  ● will hang

    TypeError: sourceMap.map.originalPositionFor is not a function

      4 | 
      5 | it("will hang", () => {
    > 6 |   expect(()=>foo("test")).not.toThrow();
      7 | })
      8 | 
      
      at mapSourcePosition (node_modules/source-map-support/source-map-support.js:199:42)
          at Array.map (<anonymous>)
      at Object.<anonymous>.it (__tests__/index.ts:6:47)

Test Suites: 1 failed, 1 total
Tests:       1 failed, 1 total
Snapshots:   0 total
Time:        2.294s
Ran all test suites.
----------|----------|----------|----------|----------|----------------|
File      |  % Stmts | % Branch |  % Funcs |  % Lines |Uncovered Lines |
----------|----------|----------|----------|----------|----------------|
All files |      100 |      100 |      100 |      100 |                |
 index.ts |      100 |      100 |      100 |      100 |                |
----------|----------|----------|----------|----------|----------------|
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

Note: I had to move the jest.unmock() before the import. When the unmocking operation happens after the import, it's silently ignored and the imported function stays a spy (because automock is true).

[kulshekhar]

@Debrice that error goes away if mapCoverage is removed from jest config. I'm not yet sure what needs to be done to fix this

I'll need to take a closer look at this. This will probably address #340 as well

[typehorror]

@kulshekhar, you are right. I decided not to mention the removal of mapCoverage since it would render the use of collectCoverage option moot. For now I just don't collect coverage during the coding process.

Once all my tests pass, I turn on collectCoverage and run another pass... it has become more or less a "first world problem" at this point.

[GeeWee]

Seems strange with the hoisting issue. We're running things through the same transform jest is, so the issue should manifest in plain jest as well if it's related to that.

[huafu]

@Debrice if this has yet not been fixed in latest version, you can test beta (see #697). Anyway, I am closing this since it's quite old, but feel free to re-open if I shouldn't have closed it of course.