Add vendor and .env to make usable

vendor/phpunit/php-code-coverage/tests/_files/CoveredClass.php

@@ -0,0 +1,36 @@
+<?php
+class CoveredParentClass
+{
+    private function privateMethod()
+    {
+    }
+
+    protected function protectedMethod()
+    {
+        $this->privateMethod();
+    }
+
+    public function publicMethod()
+    {
+        $this->protectedMethod();
+    }
+}
+
+class CoveredClass extends CoveredParentClass
+{
+    private function privateMethod()
+    {
+    }
+
+    protected function protectedMethod()
+    {
+        parent::protectedMethod();
+        $this->privateMethod();
+    }
+
+    public function publicMethod()
+    {
+        parent::publicMethod();
+        $this->protectedMethod();
+    }
+}