tests.yml

# This workflow uses actions that are not certified by GitHub.
# They are provided by a third-party and are governed by
# separate terms of service, privacy policy, and support
# documentation.

name: Build, test, and report coverage of recent files

on:
  push:
    branches:
      - master
  pull_request:
    types: [opened, synchronize, reopened]
  workflow_dispatch:

# Sets the ENV `MIX_ENV` to `test` for running tests
env:
  MIX_ENV: test
  ELIXIR_VER: '1.16.3'
  OTP_VER: '26.2.5.2'

permissions:
  contents: read

jobs:
  build:
    runs-on: ubuntu-latest
    name: Build and test

    # Set up a Postgres DB service. By default, Phoenix applications
    # use Postgres. This creates a database for running tests.
    # Additional services can be defined here if required.
    services:
      db:
        image: postgres:15
        ports: ['5432:5432']
        env:
          POSTGRES_DB: teiserver_test
          POSTGRES_USER: teiserver_test
          POSTGRES_PASSWORD: 123456789
        options: >-
          --health-cmd pg_isready
          --health-interval 10s
          --health-timeout 5s
          --health-retries 5

    steps:
    # Step: Setup Elixir + Erlang image as the base.
    - name: Set up Elixir
      uses: erlef/setup-beam@v1
      with:
        otp-version: ${{ env.OTP_VER }}
        elixir-version: ${{ env.ELIXIR_VER }}

    # Step: Check out the code.
    - name: Checkout code
      uses: actions/checkout@v4

    # Step: Define how to cache deps. Restores existing cache if present.
    - name: Cache deps
      id: cache-deps
      uses: actions/cache@v4
      env:
        cache-name: cache-elixir-deps
      with:
        path: deps
        key: ${{ runner.os }}-mix-${{ env.cache-name }}-${{ hashFiles('**/mix.lock') }}
        restore-keys: |
          ${{ runner.os }}-mix-${{ env.cache-name }}-

    # Step: Define how to cache the `_build` directory. After the first run,
    # this speeds up tests runs a lot. This includes not re-compiling our
    # project's downloaded deps every run.
    - name: Cache compiled build
      id: cache-build
      uses: actions/cache@v4
      env:
        cache-name: cache-compiled-build
      with:
        path: _build
        key: ${{ runner.os }}-mix-${{ env.cache-name }}-${{ hashFiles('**/mix.lock') }}
        restore-keys: |
          ${{ runner.os }}-mix-${{ env.cache-name }}-

    # Step: Download project dependencies. If unchanged, uses
    # the cached version.
    - name: Install dependencies
      run: mix deps.get

    # Step: Compile the current project. If unchanged, uses
    # the cached version.
    - name: Install dependencies
      run: mix compile
    
    - name: create cover folder if not exists, to cache coverage reporting results
      run: mkdir -p ./cover/    
      
    - name: emit hint on where to update minimum test coverage
      run: echo "to update minimum test coverage requirements, edit coveralls.json"

    - name: Run tests, failing loudly on error, emitting coverage to file for use when reporting test coverage in later proposed step
      run: set -eo pipefail; mix test --exclude needs_attention --cover | tee ./cover/test_coverage_by_file.txt

    # run git fetch --shallow-since far enough back to be confident we'll see some merge commits to the master branch
    # (running off the end of a shallow commit history causes git log to believe every file has changed, somehow) 
    - name: git fetch more than just the most recent commit
      run: git fetch --shallow-since="6 months"

    - name: generate list of files changed in the last month
      run: git --no-pager log --name-only --oneline --since='1 month ago' | tee ./cover/files_changed_in_last_month.txt

    - name: echo coverage header to the files_changed_in_last_month file to assist in reporting
      run: echo "LINES RELEVANT   MISSED" | tee -a ./cover/files_changed_in_last_month.txt

    - name: use grep to create test coverage report only on recently changed files, sorted by coverage percent
      run: grep -F -f ./cover/files_changed_in_last_month.txt ./cover/test_coverage_by_file.txt | grep -A999 "LINES RELEVANT   MISSED" | sort -g