Add Gitea Actions test workflow

.gitea/workflows/tests.yaml

@@ -0,0 +1,36 @@
+name: Tests
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  tests:
+    runs-on: ubuntu-latest
+    container:
+      image: php:7.4-cli
+
+    steps:
+      - name: Install system dependencies
+        run: |
+          apt-get update -qq
+          apt-get install -y -qq git unzip curl
+          curl -sS https://getcomposer.org/installer | php -- --install-dir=/usr/local/bin --filename=composer
+
+      - uses: actions/checkout@v3
+
+      - name: Install Composer dependencies
+        run: composer install --no-interaction --prefer-dist
+
+      - name: Run PHPUnit
+        run: vendor/bin/phpunit
+        if: always()
+
+      - name: Run Psalm
+        run: |
+          curl -sSL https://github.com/vimeo/psalm/releases/download/4.30.0/psalm.phar -o /usr/local/bin/psalm
+          chmod +x /usr/local/bin/psalm
+          psalm --no-cache
+        if: always()