feat: coverage diff change

[vladopajic]

some developers prefer to see coverage difference change on their PRs. go-test-coverage could be extended to allow such functionality for those who want it.

1. give new option which will show error if coverage difference from base branch is below threshold.
   diff-threshold property will set allowed threshold for coverage difference (in percentage) from base branch. for example, if this property is set to to 5 (meaning 5%), error will be shown if current PR doesn't have at least 5% more code covered. similar, if value is set to -5, PR will be allowed to have up to 5% less covered code then base branch.
   this property will stack with other rules.

2. give new option to post comment on PR with coverage difference.
   diff-comments property will control if GitHub action will post comments on PR with coverage difference.

Edit: diff-comments is not really used, see usage of breakdown-file-name and diff-base-breakdown-file-name

[vladopajic]

closing this issue as it was implemented in v2.11.0, here is the documentation and PR with example report.

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@zhongyi-zhang, @vxjohanforssell, @andriisoldatenko, @prashantv, @gemyago, hello all, i hope this comment finds you well! i am kindly notifying you about progress of this feature. happy coding 🌞

[andriisoldatenko]

@vladopajic thanks a lot for your effort! I've tried example from docs and it works, it prints comment with code coverage report.

I have a few questions regarding:

diff-comments and go-test-coverage I can't find in docs or just by searching inside source code where to set up these 2 options.

[vladopajic]

hey @andriisoldatenko,

actually diff-comments wasn't really used, and instead breakdown-file-name and diff-base-breakdown-file-name inputs control most of diff feature.

please see test.yml of this repo to see how coverage diff is used. see also docs.

[andriisoldatenko]

hey @andriisoldatenko,

actually diff-comments wasn't really used, and instead breakdown-file-name and diff-base-breakdown-file-name inputs control most of diff feature.

please see test.yml of this repo to see how coverage diff is used. see also docs.

yeah that's what I noticed! cool thanks

so you can't control diff threshold or you can? i mean this one diff-threshold 🤔

[vladopajic]

for now, you can't control diff-threshold (it's not implemented). but likely it will be implemented soon (it shouldn't be hard to implement it)

[vladopajic]

added #181 issue to track progress for diff-threshold and #182 to track progress of posting comments to PR.

initially i envisioned both to be part of this feature, but since this feature was already large i decided to merge it as just "report only". and added docs where other github action was used to post comments to PR.

#181 (diff-threshold) will likely get implemented in near future, while #182 i am not really sure when since this just doesn't add any necessary functionality.