Add automated tests

.github/workflows/tests.yml

@@ -0,0 +1,61 @@
+name: Tests
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+jobs:
+  phpUnitTests:
+    runs-on: ubuntu-latest
+    name: ubuntu-latest / PHP 7.4
+    env:
+      extensions: curl, fileinfo, gd, mbstring, openssl, pdo, pdo_sqlite, sqlite3, xml, zip
+      key: laravel-mailtrap-driver-cache
+    steps:
+      - name: Cancel previous incomplete runs
+        uses: styfle/[email protected]
+        with:
+          access_token: ${{ github.token }}
+
+      - name: Checkout changes
+        uses: actions/checkout@v2
+
+      - name: Setup extension cache
+        id: extcache
+        uses: shivammathur/cache-extensions@v1
+        with:
+          php-version: 7.4
+          extensions: ${{ env.extensions }}
+          key: ${{ env.key }}
+
+      - name: Cache extensions
+        uses: actions/cache@v2
+        with:
+          path: ${{ steps.extcache.outputs.dir }}
+          key: ${{ steps.extcache.outputs.key }}
+          restore-keys: ${{ steps.extcache.outputs.key }}
+
+      - name: Install PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: 7.4
+          extensions: ${{ env.extensions }}
+
+      - name: Setup dependency cache
+        id: composercache
+        run: echo "::set-output name=dir::$(composer config cache-files-dir)"
+
+      - name: Cache dependencies
+        uses: actions/cache@v2
+        with:
+          path: ${{ steps.composercache.outputs.dir }}
+          key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.json') }}
+          restore-keys: ${{ runner.os }}-composer-
+
+      - name: Install Composer dependencies
+        run: composer install --no-interaction --no-progress --no-scripts
+
+      - name: Run tests
+        run: vendor/bin/phpunit