Enable code coverage with whitelist and ignore output

Author: redthor

.gitignore

@@ -6,3 +6,4 @@ vendor/
 # You may choose to ignore a library lock file http://getcomposer.org/doc/02-libraries.md#lock-file
 composer.lock
 .php_cs.cache
+coverage.clover

phpunit.xml.dist

@@ -5,4 +5,14 @@
             <directory>./tests/</directory>
         </testsuite>
     </testsuites>
-</phpunit>
+
+    <filter>
+        <whitelist processUncoveredFilesFromWhitelist="true">
+            <directory suffix=".php">src</directory>
+        </whitelist>
+        <blacklist>
+            <directory>vendor</directory>
+            <directory>./tests</directory>
+        </blacklist>
+    </filter>
+</phpunit>