add PHP boilerplate

phpunit.xml

@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.2/phpunit.xsd"
+         bootstrap="vendor/autoload.php"
+         executionOrder="depends,defects"
+         forceCoversAnnotation="true"
+         beStrictAboutCoversAnnotation="true"
+         beStrictAboutOutputDuringTests="true"
+         beStrictAboutTodoAnnotatedTests="true"
+         verbose="true">
+
+    <testsuites>
+        <testsuite name="unit-tests">
+            <directory suffix="Test.php">tests/unit</directory>
+        </testsuite>
+    </testsuites>
+
+    <filter>
+        <whitelist processUncoveredFilesFromWhitelist="true">
+            <directory suffix=".php">src</directory>
+        </whitelist>
+    </filter>
+
+    <logging>
+        <log type="coverage-html" target="coverage/" lowUpperBound="60" highLowerBound="100"/>
+        <log type="coverage-text" target="php://stdout" showUncoveredFiles="false"/>
+    </logging>
+</phpunit>