Monorepository coverage diff

Introduction

This projects aims to provide a way to ease CI test coverage difference based on a coverage-summary.json file.

The process of the code is as follow:

• pull base branch (default main)
• run commands to initialize current branch and base branch coverage files (here we should run things like dependency installation, building, testing and outputing the coverage-summary.json file)
• run coverage diff between current branch and base branch project by project
• post a comment to the PR that sumarize which project has seen it's coverage changed with collapsible details

Simple configuration

Example of a easiest github workflow configuration:

name: Pull request

on:
  pull_request:
    branches:
      - main

jobs:
  build:
    runs-on: ubuntu-latest

    steps:
      - uses: actions/checkout@v3
      - name: Use Node.js ${{ matrix.node-version }}
        uses: actions/setup-node@v3

      # The important part is below
      - uses: holynoodle/monorepo-coverage-diff@v6
        with:
          token: ${{ secrets.GITHUB_TOKEN }} #required to pull the base branch and post the comment in the PR
          base: main # optional, default main
          basePath: /tmp/base # optional, default /tmp/base
          group: MyCoverageGroup # optional, default ''. This is used to separate comments if you are triggering this action multiple times
          projects: | # List of projects and path to each project, coverage file for this project will be searched at the project root
            project1:path/to/project1
            project2:path/to/project2
            project3:path/to/project3
          commands: | # List of command to run to initialize and generate the coverage file for all the projects above.
            yarn --frozen-lockfile
            yarn build
            yarn ci:unit

PR comment

Here is an example of the comment the action will write in the PR. The comment is updated with latest information:

🍜 Noodly Coverage! 🍜

These projects have a changing coverage:

Project	Lines	Statements	Functions	Branches
project3	- 4.18 (95.52%)	- 4.13 (95.57%)	- 4.10 (95.08%)	- 5.17 (93.10%)

Coverage diff details

project1

File	Lines	Statements	Functions	Branches
./src/file1.ts	0.00 (100.00%)	0.00 (100.00%)	0.00 (100.00%)	0.00 (100.00%)
./src/file2.ts	0.00 (81.25%)	0.00 (81.25%)	0.00 (83.33%)	0.00 (100.00%)
./src/file3.ts	0.00 (100.00%)	0.00 (100.00%)	0.00 (100.00%)	0.00 (100.00%)

project2

File	Lines	Statements	Functions	Branches
./src/file1.ts	0.00 (100.00%)	0.00 (100.00%)	0.00 (100.00%)	0.00 (100.00%)
./src/file2.ts	0.00 (100.00%)	0.00 (100.00%)	0.00 (100.00%)	0.00 (100.00%)

project3

File	Lines	Statements	Functions	Branches
./src/file1	0.00 (100.00%)	0.00 (100.00%)	0.00 (100.00%)	0.00 (91.66%)
./src/file2.ts	- 100.00 (0.00%)	- 100.00 (0.00%)	- 83.34 (16.66%)	- 100.00 (0.00%)

Advanced configuration

When you want to reduce the number of installs and builds, the action leave you the opportunity to only run diffs

steps:
  - uses: actions/checkout@v3
    with:
      path: ./branch
  - uses: actions/checkout@v3
    with:
      ref: main
      path: ./base

  - name: Use Node.js
    uses: actions/setup-node@v3

  - run: yarn --frozen-lockfile && yarn build && yarn ci:unit
    working-directory: ./base
  - run: yarn --frozen-lockfile && yarn build && yarn ci:unit
    working-directory: ./branch

  - uses: holynoodle/monorepo-coverage-diff@v6
    with:
      token: ${{ secrets.GITHUB_TOKEN }}
      basePath: ./base
      branchPath: ./branch
      projects: |
        project1:path/to/project1
        project2:path/to/project2
        project3:path/to/project3
      diffOnly: true