GitLab

Test coverage service

Motivation

When using GitLab, you can query your projects test coverage via the GitLab API. This package contains a service which you can utilise within your pipeline as follows.

The script will try to get the last commit inside your branch which came from your default branch (usually “develop”) and looks for a successfully run pipeline. From there, it will query the code coverage and compare it to your coverage. If it has dropped, the step will return “1” which causes your pipeline to fail. If it can’t find a valid pipeline, it will fall back to the default branches most recent successful pipeline.

Take care that you have to set up Gitalb to recognise your coverage before you can use this functionality.

Installation

  • Create a file called scripts/validate_coverage.py and add the following:

from ambient_toolbox.gitlab.coverage import CoverageService

service = CoverageService()
service.process()

  • Add this step to your gitlab-ci.yml. Make sure that you set the correct python version and that this stage is defined after the unittest stage.

# POST-TEST STAGE
check coverage:
  image: ${CI_DEPENDENCY_PROXY_GROUP_IMAGE_PREFIX}/python:3.12
  stage: posttest
  needs:
    - unittest
  tags:
    - low-load
  except:
    - develop
    - master
  before_script:
    - pip install -U pip httpx ambient_toolbox
  script:
    - python scripts/validate_coverage.py

  • Create an access token for your repo having developer role and read_api permission (Settings -> Access Tokens)

  • Add two variables to your CI/CD inside your GitLab repository (Settings -> CI/CD -> Variables). Insert the token from step 3 and define your default branch for comparison. Usually, this will be “develop”.

GITLAB_CI_COVERAGE_PIPELINE_TOKEN = [token]

GITLAB_CI_COVERAGE_TARGET_BRANCH = develop

CI_COVERAGE_JOB_NAME = [pipeline step name for your backend tests job]

  • Done. Enjoy!

Hint: For merge-commits (i.e.: Merge develop into master), or hotfixes into branches that are not your default, manually run a Pipeline on your source-branch (i.e.: develop if you want to merge develop into master) with the Input variable key set to GITLAB_CI_COVERAGE_TARGET_BRANCH and the Input variable value set to the target branch ( i.e.: master if you want to merge develop into master).

Hint: If you wish to not run coverage for a specific pipeline for whatever reason, simply run the pipeline with GITLAB_CI_DISABLE_COVERAGE = True and no coverage will be collected.