name: Elixir CI

on:
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]

jobs:
  build:

    name: Build and test
    runs-on: ubuntu-16.04
    env:
      MIX_ENV: test
    strategy:
      fail-fast: false
      matrix:
        include:
          - pair:
              elixir: 1.6.6
              otp: 19.3.6.13
          - pair:
              elixir: 1.11.4
              otp: 23.3
            lint: lint
    steps:
    - uses: actions/checkout@v2

    - name: Set up Elixir
      uses: erlef/setup-elixir@v1
      with:
        otp-version: ${{matrix.pair.otp}}
        elixir-version: ${{matrix.pair.elixir}}

    - name: Restore dependencies cache
      uses: actions/cache@v2
      with:
        path: deps
        key: ${{ runner.os }}-mix-${{ hashFiles('**/mix.lock') }}
        restore-keys: ${{ runner.os }}-mix-

    - name: Install Dependencies
      run: mix deps.get --only test

    - run: mix format --check-formatted
      if: ${{ matrix.lint }}

    - run: mix deps.get && mix deps.unlock --check-unused
      if: ${{ matrix.lint }}

    - run: mix deps.compile

    - run: mix compile --warnings-as-errors
      if: ${{ matrix.lint }}

    - run: mix test