jest: jest --watch doesn't show coverage in Vue

at this stage, I think this is actually a feature.

–watch is meant to run tests only on files that both:

1. has a test(s)
2. have been changed

–watchAll runs all tests on every file change.

IMO it’s just a little confusing for newbies (like myself) when using --watch and seeing no output. Perhaps this is an opportunity for clarification in the docs to make it absolutely obvious?? at this stage, i don’t think it’s a bug. In fact it’s actually quite smart as it wont waste time running tests on files that have not changed.

Same here in React after upgrade react-scripts 2.1.8 => 3.0.0

react-scripts test --coverage

File	% Stmts	% Branch	% Funcs	% Lines	Uncovered Line #s
All files	0	0	0	0

Test Suites: 56 passed, 56 total Tests: 308 passed, 308 total Snapshots: 0 total Time: 20.996s, estimated 21s Ran all test suites.

Watch Usage: Press w to show more.

And I try to use create-react-app to creat an new app, copy my code and paste in new-app folder. Run “react-scripts test --coverage” again. It works!?

File	% Stmts	% Branch	% Funcs	% Lines	Uncovered Line #s
All files	100	100	100	100
components/App	100	100	100	100
…	100	100	100	100

Test Suites: 56 passed, 56 total Tests: 308 passed, 308 total Snapshots: 0 total Time: 24.253s Ran all test suites related to changed files.

Then I copy all code include “node_modules” in new-app folder and paste in my old object. No coverage again, always be empty

File	% Stmts	% Branch	% Funcs	% Lines	Uncovered Line #s
All files	0	0	0	0

???

envinfo

System: OS: Windows 10 CPU: (4) x64 Intel® Core™ i5-7500 CPU @ 3.40GHz Binaries: Node: 8.14.0 - D:\nodejs\node.EXE Yarn: 1.12.3 - C:\Users\DELL\AppData\Roaming\npm\yarn.CMD npm: 6.4.1 - D:\nodejs\npm.CMD

I notice that jest only tests files that are not in a git commit. To test files that regardless of git status i used --watchAll to get around this.

I was having the same issue. With Jest version 24.9.0 if I add --watchAll=false or --watchAll=false it works. Apparently is the only presence of --watchAll flag, at least for me.

I’m experiencing this as well in a vanilla NodeJS project.

$ npx jest
 PASS  __tests__/index.js
 PASS  __tests__/compat.js
-----------|----------|----------|----------|----------|-------------------|
File       |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
-----------|----------|----------|----------|----------|-------------------|
All files  |    31.25 |    10.34 |    53.85 |       35 |                   |
 compat.js |     17.5 |      3.7 |    33.33 |    21.21 |... 60,61,77,78,82 |
 index.js  |      100 |      100 |      100 |      100 |                   |
-----------|----------|----------|----------|----------|-------------------|

Test Suites: 2 passed, 2 total
Tests:       6 passed, 6 total
Snapshots:   0 total
Time:        2.298s
Ran all test suites.

$ npx jest --watch
 PASS  __tests__/compat.js
 PASS  __tests__/index.js
-----------|----------|----------|----------|----------|-------------------|
File       |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
-----------|----------|----------|----------|----------|-------------------|
All files  |     17.5 |      3.7 |    33.33 |    21.21 |                   |
 compat.js |     17.5 |      3.7 |    33.33 |    21.21 |... 60,61,77,78,82 |
-----------|----------|----------|----------|----------|-------------------|

Test Suites: 2 passed, 2 total
Tests:       6 passed, 6 total
Snapshots:   0 total
Time:        2.504s
Ran all test suites related to changed files.

When run with --watch note that coverage for index.js is not reported.

Interestingly, when using --watch, if I make a change in index.js that causes a test to fail then coverage for index.js will be reported. However, if I instead make a change in __tests__/index.js that causes a test to fail then coverage for index.js is not reported.

envinfo

npx envinfo --preset jest
npx: installed 1 in 1.469s

  System:
    OS: macOS High Sierra 10.13.6
    CPU: (8) x64 Intel(R) Core(TM) i7-3820QM CPU @ 2.70GHz
  Binaries:
    Node: 10.15.3 - ~/.local/nodeenv/lts/bin/node
    Yarn: 1.15.2 - ~/.local/nodeenv/lts/bin/yarn
    npm: 6.9.0 - ~/.local/nodeenv/lts/bin/npm
  npmPackages:
    jest: 24.7.1 => 24.7.1