Measure test coverage

[CSchoel]

• [ ] Generate code coverage reports from your test suite
  • Suggested sources for help: google "java code coverage", or "codecov java"
• [ ] Upload coverage reports manually to a tool like Codecov.io
  • Suggested sources for help: manually browsing through the Codecov.io docs
• [ ] Integrate coverage reports into CI pipeline in GitHub Actions
  • Suggested sources for help: google "codecov github actions", manually browsing through the Codecov.io docs
• [ ] Add a badge to the README that shows the code coverage

[CSchoel]

As requested, here is your HowTo for setting up codecov:

• Install the Codecov GitHub App for the MopeSWTP-SS21 organization and grant access only to this repository.
• Login on Codecov.io with your GitHub account.
• You should be able to see your project in your dashboard with the text "No data available" in the test coverage column. Click on the project and copy the upload token that is displayed.
• Save the upload token as an encrypted environment variable in the repository:
  • From the repository main page go to Settings -> Secrets -> New repository secret.
  • Enter CODECOV_TOKEN as name and the copied token from the previous (top-level) step as value.
  • Click "Add secret".
• Enable Jacoco in the Gradle settings:
  • I have already done this in the [feature/sonarQube branch](https://github.com/MopeSWTP-SS21/MopeSWTP/compare/feature/sonarQube, but feel free to also do it yourself on your own feature branch. The merge conflicts should not be too much of an issue. The optimal strategy would be to cherry-pick my existing commit, but you don't have to do that.
  • If you want to do it manually, you need to add the changes in example 1 and 2 in the Jacoco plugin documentation to your build.gradle.
  • You also need to add the following code to configure the jacocoTestReport task to generate reports in XML format (see the Gradle example repository):

    reports {
        xml.enabled true
        html.enabled false
    }

• Update the CI script to create and upload test reports:

  • Create test reports with ./gradlew jacocoTestReport

  • Upload test reports with:

    curl -Os https://uploader.codecov.io/latest/linux/codecov 
    chmod +x codecov
    ./codecov -t ${CODECOV_TOKEN}

Resources:

• Codecov quick start
• GitHub docs about encrypted secrets
• codecov/example-gradle
• Jacoco Gradle plugin docs
• Blog post about Codecov uploader

[CSchoel]

Update: When #116 is merged, you can use the Jacoco Gradle settings that I already implemented for the code coverage reports for SonarQube.