diff --git a/.travis.yml b/.travis.yml
index 18c5c68..7632745 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,7 +8,7 @@ install:
 - if [ "$TRAVIS_OS_NAME" = "osx" ]; then bash package/prepare_osx.sh; fi
 - if [ "$TRAVIS_OS_NAME" = "linux" ]; then bash package/prepare_linux.sh; fi
 script:
-- if [ "$TRAVIS_OS_NAME" = "osx" ]; then python3 -m pytest -vs; fi
+- if [ "$TRAVIS_OS_NAME" = "osx" ]; then python3 -B -m pytest -vs; fi
 - if [ "$TRAVIS_OS_NAME" = "linux" ]; then xvfb-run -s '-screen 0 640x480x24 +extension GLX' pytest -vs; fi
 before_deploy:
 - export FILENAME=manuskript-$TRAVIS_BRANCH-$TRAVIS_OS_NAME.zip