create-react-app: test coverage is empty - v3.0.0

Is this a bug report?

yes, test coverage is always empty

After updating react-scripts to 3.0.0 test coverage is always empty, this worked before in v2.1.8

v2.1.8

v3.0.0

Did you try recovering your dependencies?

This happens after booting an app up using create react app using typescript create-react-app cra-coverage-example --typescript

Which terms did you search for in User Guide?

n/a

Environment

Environment Info:

  System:
    OS: macOS 10.14.4
    CPU: x64 Intel(R) Core(TM) i5-7360U CPU @ 2.30GHz
  Binaries:
    Node: 11.12.0 - ~/.nvm/versions/node/v11.12.0/bin/node
    Yarn: 1.15.2 - /usr/local/bin/yarn
    npm: 6.7.0 - ~/.nvm/versions/node/v11.12.0/bin/npm
  Browsers:
    Chrome: 73.0.3683.103
    Safari: 12.1
  npmPackages:
    react: ^16.8.6 => 16.8.6
    react-dom: ^16.8.6 => 16.8.6
    react-scripts: 3.0.0 => 3.0.0
  npmGlobalPackages:
    create-react-app: Not Found

Steps to Reproduce

create-react-app cra-coverage-example --typescript
yarn test --coverage

Expected Behavior

test coverage would be output

Actual Behavior

test coverage is always empty

Reproducible Demo

https://github.com/pete-redmond-cko/cra-coverage-example or you can spin up an app using create react app v.3.0.0 and run yarn test --coverage

About this issue

Original URL
State: closed
Created 5 years ago
Reactions: 19
Comments: 39 (2 by maintainers)

Commits related to this issue

Added working coverage command. Per https://github.com/facebook/create-react-app/issues/6888 — committed to DevUnltd/js-library-boilerplate by hodgef 5 years ago
kent example — committed to lugithub/rabbit by lugithub 5 years ago

Most upvoted comments

If you turn off watch via: yarn test --coverage --watchAll=false

It will work properly. Looks like a Jest bug. @stipsan

+36

bugzpodder on Apr 24, 2019

Jest needs more Jest tests to test the Jest.

mraak on Apr 29, 2019

try this one

npm run test -- --coverage --watchAll=false

davidnguyen11 on May 23, 2019

If you turn off watch via: yarn test --coverage --watchAll=false

It will work properly. Looks like a Jest bug. @stipsan

It doesn’t fix it for me though. Still getting empty results

aenciso on Apr 26, 2019

At this point, I haven’t seen a legit bug except for in a minor case (pressing ‘a’ in watch mode doesn’t retroactive show coverage). In all cases the feature is working as expected. If you disagree, please file a new issue with a clean repro so we can investigate. Thanks!

bugzpodder on May 23, 2019

@sketchbuch For npm, you’ll need an extra set of dashes to get watchAll flag to work, something like: npm run test:c -- --watchAll=false, which produces result:

-----------------------------------------|----------|----------|----------|----------|-------------------|
File                                     |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
-----------------------------------------|----------|----------|----------|----------|-------------------|
All files                                |    56.75 |    47.32 |    47.87 |    57.32 |                   |
 src                                     |        0 |        0 |        0 |        0 |                   |
  index.js                               |        0 |      100 |      100 |        0 |                10 |
  registerServiceWorker.js               |        0 |        0 |        0 |        0 |... 87,91,96,97,98 |
 src/js/actions                          |    98.16 |    81.82 |    98.68 |    98.16 |                   |
  appActions.js                          |      100 |      100 |      100 |      100 |                   |
  builderActions.js                      |      100 |      100 |      100 |      100 |                   |
  categoryActions.js                     |      100 |      100 |      100 |      100 |                   |
  classActions.js                        |      100 |      100 |      100 |      100 |                   |
  dataActions.js                         |      100 |      100 |      100 |      100 |                   |

Here I’ve changed one file, and the coverage also works correctly:

git diff
diff --git a/src/js/actions/appActions.js b/src/js/actions/appActions.js
index 225a476..a5513a5 100644
--- a/src/js/actions/appActions.js
+++ b/src/js/actions/appActions.js
@@ -1,4 +1,5 @@
 // @flow
+console.log('foo');
 
 import { APP_ERRORED, APP_LOADED } from '../constants/actionTypes';
 import type { ActionCreator } from '../types/action';

 PASS  src/js/actions/tests/appActions.test.js
  ● Console

    console.log src/js/actions/appActions.js:2
      foo

 PASS  src/js/components/App/App.test.js
  ● Console

    console.log src/js/actions/appActions.js:2
      foo

---------------|----------|----------|----------|----------|-------------------|
File           |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
---------------|----------|----------|----------|----------|-------------------|
All files      |      100 |      100 |      100 |      100 |                   |
 appActions.js |      100 |      100 |      100 |      100 |                   |
---------------|----------|----------|----------|----------|-------------------|

Test Suites: 2 passed, 2 total
Tests:       5 passed, 5 total
Snapshots:   0 total
Time:        3.256s, estimated 6s
Ran all test suites related to changed files.

Watch Usage
 › Press a to run all tests.
 › Press f to run only failed tests.
 › Press q to quit watch mode.
 › Press p to filter by a filename regex pattern.
 › Press t to filter by a test name regex pattern.
 › Press Enter to trigger a test run.

bugzpodder on May 11, 2019

I have the same problem (v3.0.1). I can’t run coverage at all. It used to work, this is my repo: https://github.com/sketchbuch/school-report

when I run > npm run test:c

it says no tests have changed. --watchAll or --watchAll=false does nothing. Pressing “a” runs the tests but produces no coverage or even runs coverage. The coverage folder is created but contains just a few files - mostly little images used in the report display.

sketchbuch on May 11, 2019