Add test coverage job

.github/workflows/ci.yml

@@ -79,3 +79,67 @@ jobs:
     - name: Run tests
       run: mix test
 
+  coverage:
+    services:
+      db:
+        image: postgres:15
+        ports: ['5432:5432']
+        env:
+          POSTGRES_PASSWORD: postgres
+        options: >-
+          --health-cmd pg_isready
+          --health-interval 10s
+          --health-timeout 5s
+          --health-retries 5
+
+    runs-on: ubuntu-latest
+    name: Test on OTP ${{matrix.otp}} / Elixir ${{matrix.elixir}}
+    strategy:
+      matrix:
+        otp: ['26.2.5']
+        elixir: ['1.16.2']
+    steps:
+    - name: Set up Elixir
+      uses: erlef/setup-beam@v1
+      with:
+        otp-version: ${{matrix.otp}}
+        elixir-version: ${{matrix.elixir}}
+
+    - name: Checkout code
+      uses: actions/checkout@v3
+
+    - name: Cache deps
+      id: cache-deps
+      uses: actions/cache@v3
+      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 }}-
+
+    - name: Cache compiled build
+      id: cache-build
+      uses: actions/cache@v3
+      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 }}-
+          ${{ runner.os }}-mix-
+
+    - name: Install dependencies
+      run: mix deps.get
+
+    - name: Compiles without warnings
+      run: mix compile --warnings-as-errors
+
+    - name: Check Formatting
+      run: mix format --check-formatted
+
+    - name: Run tests with coverage
+      run: mix test.cover
+