Add PHPUnit tests on CI

.github/workflows/phpunit.yml

@@ -0,0 +1,48 @@
+name: PHPUnit
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  test:
+    name: Test & Upload coverage.xml to Codecov
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout Code
+        uses: actions/checkout@v4
+
+      - name: Setup PHP 8.2
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: 8.2
+
+      - name: Check PHP Version
+        run: php -v
+
+      - name: Install Composer Dependencies
+        run: composer install --no-interaction --prefer-dist
+
+      - name: Run tests via PHPUnit
+        env:
+          XDEBUG_MODE: coverage
+        run: |
+          vendor/bin/phpunit --coverage-clover=coverage.xml
+          cat ./coverage.xml
+
+      - name: Show coverage.xml
+        run: cat ./coverage.xml
+
+      - name: Upload coverage.xml to Codecov
+        uses: codecov/codecov-action@v3
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
+          files: ./coverage.xml
+          fail_ci_if_error: true
+          flags: unittests
+          name: codecov-umbrella
+          verbose: true
+          env_vars: PHP

phpunit.xml

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/10.3/phpunit.xsd" bootstrap="vendor/autoload.php" colors="true" cacheDirectory=".phpunit.cache">
+    <testsuites>
+        <testsuite name="Tests">
+            <directory suffix="Test.php">./tests</directory>
+        </testsuite>
+    </testsuites>
+    <coverage/>
+    <source>
+        <include>
+            <directory suffix=".php">./src</directory>
+        </include>
+    </source>
+</phpunit>