diff --git a/.travis.yml b/.travis.yml
index 3d99589dd9a047553f193838aaa32e4392fde5be..b6ecc5f213cb54dfeaad8f41d41c6fe734c0dc8e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -97,7 +97,7 @@ jobs:
       env: Codecov
       before_script:
         - composer update
-        - php vendor/bin/phpunit
+        - XDEBUG_MODE=coverage php vendor/bin/phpunit
       script:
         - bash <(curl -s https://codecov.io/bash)