Add Github Actions workflow definition

.editorconfig

@@ -10,3 +10,6 @@ insert_final_newline = true
 
 [*.md]
 trim_trailing_whitespace = false
+
+[*.{yml,yaml}]
+indent_size = 2

.gitattributes

@@ -1,3 +1,8 @@
 /.gitattributes export-ignore
 /.gitignore     export-ignore
 /.editorconfig  export-ignore
+/tests          export-ignore
+/phpcs.xml      export-ignore
+/phpunit.xml    export-ignore
+/psalm.xml      export-ignore
+/.github        export-ignore

.github/workflows/test.yml

@@ -0,0 +1,35 @@
+name: Test
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    types:
+      - opened
+      - synchronize
+
+jobs:
+  test:
+    name: Test
+    strategy:
+      matrix:
+        php: [ "7.1", "7.2", "7.3", "7.4", "8.0", "8.1", "8.2" ]
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: "${{ matrix.php }}"
+          extensions: mbstring, pcre
+          tools: composer:v2
+          coverage: none
+
+      - name: Install dependencies
+        run: composer install --no-progress --no-interaction --no-ansi
+
+      - name: Test
+        run: composer check