diff --git a/phpunit.xml b/phpunit.xml
index 4772d96..4a48f59 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -18,7 +18,7 @@
     <php>
         <ini name="date.timezone" value="UTC"/>
         <env name="APP_ENV" value="testing"/>
-        <env name="TEST_MODE" value="override"/>
+        <env name="TEST_MODE" value="_override"/>
     </php>
     <logging>
         <log type="coverage-clover" target="build/logs/clover.xml"/>