diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 0a1b4f3..e118f02 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -7,23 +7,28 @@
 		 convertErrorsToExceptions="true"
 		 convertNoticesToExceptions="true"
 		 convertWarningsToExceptions="true"
-		 processIsolation="false"
+		 processIsolation="true"
 		 stopOnFailure="false">
 	<testsuites>
 		<testsuite name="Test Suite">
 			<directory suffix=".php">./tests</directory>
 		</testsuite>
 	</testsuites>
-    <php>
-        <env name="APP_ENV" value="testing"/>
+	<filter>
+		<whitelist>
+			<directory suffix=".php">src/</directory>
+		</whitelist>
+	</filter>
+	<php>
+		<env name="API_DEBUG" value="false"/>
+		<env name="APP_ENV" value="testing"/>
 		<env name="APP_URL" value="http://localhost/"/>
-        <env name="CACHE_DRIVER" value="array"/>
-        <env name="SESSION_DRIVER" value="array"/>
-        <env name="QUEUE_DRIVER" value="sync"/>
-        <env name="MAIL_DRIVER" value="array"/>
+		<env name="CACHE_DRIVER" value="array"/>
 		<env name="DB_CONNECTION" value="sqlite"/>
 		<env name="DB_DATABASE" value=":memory:"/>
-		<env name="API_DEBUG" value="false"/>
+		<env name="QUEUE_DRIVER" value="sync"/>
+		<env name="SESSION_DRIVER" value="array"/>
+		<env name="MAIL_DRIVER" value="array"/>
 		<ini name="memory_limit" value="512M" />
-    </php>
+	</php>
 </phpunit>