name: Elixir CI

on:
  push:
    branches: [master]
  pull_request:
    branches: [master]
jobs:
  build:
    runs-on: ubuntu-latest
    name: OTP ${{matrix.otp}} / Elixir ${{matrix.elixir}}
    strategy:
      matrix:
        otp: ["22.2", "23"]
        elixir: ["1.9.4", "1.10.0"]
    steps:
      - run: sudo apt-get install --yes erlang-dev
      - uses: actions/checkout@v2
      - uses: actions/setup-elixir@v1
        with:
          otp-version: ${{matrix.otp}}
          elixir-version: ${{matrix.elixir}}
      - run: mix deps.get
      - uses: actions/cache@v1
        id: cache-deps
        with:
          path: deps
          key: ${{matrix.otp}}-${{matrix.elixir}}-mix-${{ hashFiles(format('{0}{1}', github.workspace, '/mix.lock')) }}
          restore-keys: ${{matrix.otp}}-${{matrix.elixir}}-mix-
      - uses: actions/cache@v1
        id: cache-build
        with:
          path: _build
          # We may need to include elixir/OTP version in this cache key
          key: ${{matrix.otp}}-${{matrix.elixir}}-build-${{ hashFiles('mix.lock') }}
          restore-keys: |
            ${{matrix.otp}}-${{matrix.elixir}}-build-
      - run: mix deps.get
      - run: |
          mix compile --warnings-as-errors
          MIX_ENV=test mix compile --warnings-as-errors
      - run: mix check