Add test workflow

Author: JulianVennen

.github/workflows/tests.yaml

@@ -0,0 +1,44 @@
+name: Tests
+
+on:
+  workflow_dispatch:
+  pull_request:
+  push:
+    branches:
+      - master
+
+jobs:
+  tests:
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        php-version: [ '8.1', '8.2', '8.3', '8.4' ]
+
+    name: Run tests on PHP v${{ matrix.php-version }}
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php-version }}
+
+      - name: Set composer cache directory
+        id: composer-cache
+        run: echo "COMPOSER_CACHE_DIRECTORY=$(composer config cache-files-dir)" >> $GITHUB_ENV
+
+      - name: Restore composer from cache
+        uses: actions/cache@v4
+        with:
+          path: ${{ env.COMPOSER_CACHE_DIRECTORY }}
+          key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}
+          restore-keys: ${{ runner.os }}-composer-
+
+      - name: Install composer dependencies
+        run: composer install --no-interaction --prefer-dist --no-progress
+
+      - name: Run phpunit tests
+        run: vendor/bin/phpunit --colors=always --testdox