Add GitHub action to run PHP tests

.github/workflows/php-tests.yml

@@ -0,0 +1,52 @@
+name: PHP Tests
+
+on:
+  push:
+    branches: [ "master" ]
+  pull_request:
+    branches: [ "master" ]
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    services:
+      redis:
+        image: redis
+        options: >-
+          --health-cmd "redis-cli ping"
+          --health-interval 10s
+          --health-timeout 5s
+          --health-retries 5
+        ports:
+          - 6379:6379
+
+    steps:
+      - name: Check out repository code
+        uses: actions/checkout@v3
+
+      - name: Start MySQL
+        run: |
+          sudo /etc/init.d/mysql start
+
+      - name: Cache Composer packages
+        id: composer-cache
+        uses: actions/cache@v3
+        with:
+          path: vendor
+          key: ${{ runner.os }}-php-${{ hashFiles('**/composer.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-php-
+
+      - name: Install dependencies
+        run: composer install --prefer-dist --no-progress
+
+      - name: Write to config file
+        run: |
+          echo test-db-password = root > config.ini
+
+      - name: Run test suite
+        run: composer run-script test-lin