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Bervianto Leo Pratama
Bervianto Leo Pratama

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Coverage Report for Elixir & Phoenix


Hello, I am new at Elixir and Phoenix. I curious about DevOps aspects and Backend aspects. So, that is why I explore more about coverage report and automatic testing. I found great alternative about coverage report, that is ExCoveralls.

Setup ExCoveralls to Existing Phoenix Project

You can check the settings section of ExCoveralls, here. Please refer to their newest settings, this settings might be outdated for later.

  • Add this to project at mix.exs.
def project do
    ..., # existing settings
    deps: deps(),
    test_coverage: [tool: ExCoveralls],
    preferred_cli_env: [
      coveralls: :test,
      "coveralls.detail": :test,
      "": :test,
      "coveralls.html": :test
    # if you want to use espec,
    # test_coverage: [tool: ExCoveralls, test_task: "espec"]
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  • Add this to deps at mix.exs
defp deps do
    ..., # existing dependencies
    {:excoveralls, "~> 0.10", only: :test},
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  • Create new file with name coveralls.json in the root project. This settings to ignore test and deps folder become coverage area.
  "skip_files": [
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  • To test if it's already installed and works. You can run this command.
MIX_ENV=test mix coveralls
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Setup Github Action

I use Github Action as my main CI/CD platform. Currently I use this configuration.

name: Elixir CI
    branches: [ main ]
    branches: [ main ]
    name: Build and test
    runs-on: ubuntu-20.04
      # Label used to access the service container
        # Docker Hub image
        image: postgres:13-alpine
        # Provide the password for postgres
          POSTGRES_PASSWORD: postgres
        # Set health checks to wait until postgres has started
        options: >-
          --health-cmd pg_isready
          --health-interval 10s
          --health-timeout 5s
          --health-retries 5
          # Maps tcp port 5432 on service container to the host
          - 5432:5432
    - uses: actions/checkout@v2
    - uses: erlef/setup-beam@v1
        otp-version: '22.2'
        elixir-version: '1.10'
    - name: Restore dependencies cache
      uses: actions/cache@v2
        path: deps
        key: ${{ runner.os }}-mix-${{ hashFiles('**/mix.lock') }}
        restore-keys: ${{ runner.os }}-mix-
    - name: Install dependencies
      run: mix deps.get
    - name: Check Format
      run: mix format --check-formatted
    - name: Run tests
      run: mix coveralls.json
        MIX_ENV: test
    - name: Upload to Codecov
      run: |
        curl -Os
        chmod +x codecov
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This configuration will automatically to add coverage results to Codecov. The result will be like this.

Codecov Result

Note: The configuration will work for public repository. If you use private repository, please consider modify the configuration. You need to change the line of ./codecov become ./codecov -t ${CODECOV_TOKEN}.

Here is my example app.

GitHub logo berviantoleo / elixir-exploration

Explore more about elixir



To start your Phoenix server:

  • Install dependencies with mix deps.get
  • Create and migrate your database with mix ecto.setup
  • Start Phoenix endpoint with mix phx.server

Now you can visit localhost:4000 from your browser.

Ready to run in production? Please check our deployment guides.

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Top comments (1)

hminy572 profile image

Thanks for sharing!