Disabling debug class loader in test environment to hide deprecation warnings.

phpunit.xml.dist

@@ -19,6 +19,17 @@
         </testsuite>
     </testsuites>
 
+    <listeners>
+        <listener class="Symfony\Bridge\PhpUnit\SymfonyTestsListener">
+            <arguments>
+                <array>
+                    <!-- set this option to 0 to disable the DebugClassLoader integration -->
+                    <element key="debug-class-loader"><integer>0</integer></element>
+                </array>
+            </arguments>
+        </listener>
+    </listeners>
+
     <filter>
         <whitelist>
             <directory>src</directory>