Update phpunit config

We can prevent risky tests, warnings and tests that doesn't test anything.

Author: vinkla

phpunit.xml.dist

@@ -1,12 +1,15 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <phpunit backupGlobals="false"
          backupStaticAttributes="false"
+         beStrictAboutTestsThatDoNotTestAnything="true"
          beStrictAboutOutputDuringTests="true"
          bootstrap="vendor/autoload.php"
          colors="true"
          convertErrorsToExceptions="true"
          convertNoticesToExceptions="true"
          convertWarningsToExceptions="true"
+         failOnRisky="true"
+         failOnWarning="true"
          processIsolation="false"
          stopOnError="false"
          stopOnFailure="false"