Fix empty coverage report

[bryanjtc]

Fixes: #313
This pull request introduces a code change aimed at resolving the issue of an empty coverage report in the project. The previous code checked whether the STORYBOOK_COLLECT_COVERAGE environment variable was not equal to 'true' before calling the reportCoverage() function. However, this approach did not cover all necessary conditions to ensure an accurate coverage report.

The new code includes an additional check to verify that both the STORYBOOK_COLLECT_COVERAGE environment variable is equal to 'true' and the JEST_SHARD environment variable is not equal to 'true'. This ensures that coverage reporting occurs only when both conditions are met, providing a more accurate assessment of test coverage.

By adding the process.env.JEST_SHARD !== 'true' condition, we prevent coverage reporting during Jest sharding, which helps prevent conflicts and inaccuracies in the coverage data.

📦 Published PR as canary version: 0.11.1--canary.324.e7f9b28.0

✨ Test out this PR locally via:

npm install @storybook/[email protected]
# or 
yarn add @storybook/[email protected]

Version

Published prerelease version: v0.11.1-next.0

Changelog

🐛 Bug Fix

• Fix empty coverage report #324 (@bryanjtc @yannbf)
• docs: fix github actions example for shard usage #320 (@MH4GF)

Authors: 3

• Bryan Thomas (@bryanjtc)
• Hirotaka Miyagi (@MH4GF)
• Yann Braga (@yannbf)

[codecov]

Codecov Report

Patch coverage has no change and project coverage change: +1.32 🎉

Comparison is base (2aa338d) 75.30% compared to head (e7f9b28) 76.63%.

Additional details and impacted files

@@            Coverage Diff             @@
##             next     #324      +/-   ##
==========================================
+ Coverage   75.30%   76.63%   +1.32%     
==========================================
  Files           8       11       +3     
  Lines         166      184      +18     
  Branches       35       39       +4     
==========================================
+ Hits          125      141      +16     
- Misses         41       43       +2     

see 3 files with indirect coverage changes

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[yannbf]

Thanks @bryanjtc ! Can you also check the following line

test-runner/src/test-storybook.ts

Line 74 in 2aa338d

if (process.env.JEST_SHARD !== 'true') {

[bryanjtc]

@yannbf Done

[yannbf]

Hey @bryanjtc thanks! Thinking more about it, it seems like the logic is not correct.

The recipe you wrote tells people to:

mv coverage/storybook/coverage-storybook.json coverage/storybook/coverage-storybook-${matrix.shard}.json

And the logic in this PR doesn't run the coverage code when shard mode is on, so in the end you don't get the coverage/storybook/coverage-storybook.json file (but you do get the .nyc_output directory from jest-playwright). I fixed the logic so that:

• coverage is always generated when --coverage is passed
• coverage is only reported when --coverage is passed and --shard is NOT passed

let me know if that aligns with what you had in mind!

[bryanjtc]

@yannbf yeah, it's ok

[github-actions]

🚀 PR was released in v0.12.0 🚀