jest-coveragedata-null

This repro was created to reproduce jest #7758

Setup

Clone and then:

$ npm i
$ npm test

Expected output

$ npm test                                                                           

> [email protected] test ~/git/jest-coveragedata-null
> jest --coverage

PASS  ./coveredFile-test.js
coveredFile
    ✓ returns false (3ms)

-------------------|----------|----------|----------|----------|-------------------|
File               |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
-------------------|----------|----------|----------|----------|-------------------|
All files          |       50 |       50 |       50 |    66.67 |                   |
coveredFile.js     |    66.67 |       50 |      100 |      100 |                 2 |
notcoveredFile.js  |        0 |      100 |        0 |        0 |                 2 |
-------------------|----------|----------|----------|----------|-------------------|
Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        1.549s
Ran all test suites.

Actual output

npm test

> [email protected] test ~/git/jest-coveragedata-null
> jest --coverage

PASS  ./coveredFile-test.js
coveredFile
    ✓ returns false (2ms)

Running coverage on untested files...Failed to collect coverage from ~/git/jest-coveragedata-null/notcoveredFile.js
ERROR: Cannot read property 'coverageData' of null
STACK: TypeError: Cannot read property 'coverageData' of null
    at _default (~/git/jest-coveragedata-null/node_modules/jest/node_modules/jest-cli/build/generateEmptyCoverage.js:72:44)
    at Object.worker (~/git/jest-coveragedata-null/node_modules/jest/node_modules/jest-cli/build/reporters/coverage_worker.js:51:45)
    at execFunction (~/git/jest-coveragedata-null/node_modules/jest-worker/build/workers/processChild.js:165:17)
    at execHelper (~/git/jest-coveragedata-null/node_modules/jest-worker/build/workers/processChild.js:149:5)
    at execMethod (~/git/jest-coveragedata-null/node_modules/jest-worker/build/workers/processChild.js:153:5)
    at process.on.request (~/git/jest-coveragedata-null/node_modules/jest-worker/build/workers/processChild.js:72:7)
    at process.emit (events.js:182:13)
    at emit (internal/child_process.js:812:12)
    at process._tickCallback (internal/process/next_tick.js:63:19)
----------------|----------|----------|----------|----------|-------------------|
File            |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
----------------|----------|----------|----------|----------|-------------------|
All files       |    66.67 |       50 |      100 |      100 |                   |
coveredFile.js |    66.67 |       50 |      100 |      100 |                 2 |
----------------|----------|----------|----------|----------|-------------------|
Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        1.73s
Ran all test suites.

How I fixed it

On my machine, updating babel-jest to ^24.0.0 solves the issue.