Watch for source code coverage growth

We are lazy, getting older, forget thing and sometimes hate unit tests :-) This tool aimed to help us not to forget improve code coverage for a new functionality we add.

istanbul-coverage-warden is supposed to be executed during pull request build and during main branch build. Main brach build should use copy command to expose gathered code coverage staticstics to S3 bucket for later use.

Pull request builder shoud use check command, and specify branch it build against. check command then download main branch code coverage metrics and check against current code coverage. If any source code file has lower LineRate than main branch, it exit with non-zero code and fail pull request build.

istanbul-coverage-warden copy \
  -d my-project-codecoverage-check \
  -b master \
  -f ./cobertura-coverage.xml

istanbul-coverage-warden check \
  -d my-project-codecoverage-check \
  -b master \
  -f ./cobertura-coverage.xml

Pull request build job should provide branch name your PR made agains. For Jenkins Github Pull Request plugin you might use ghprbTargetBranch parameter.

Then check for return codes:

• 0 - Success
• 1 - Coverage dropped, build should fail
• 2 - File open error (might be first build)

If you have ready binarry, just copy it to Jenkins. It should not require any dependencies. If you need to build it, follow the following steps:

https://golang.org/doc/install

go get -u github.com/yury-sannikov/istanbul-coverage-warden

It should download and build binary