diff --git a/.travis.yml b/.travis.yml
index 5c72397..cbab4bf 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -22,6 +22,7 @@ install:
     - pip install sphinx sphinx_rtd_theme
 
 script:
+    - grep -P -n "(\t|\s$)" *.rst mef/*.rst >> _warnings || echo "Great, no tabs or trailing spaces!"
     - spell -n -o -d en_us.ascii.add.spl mef/* | grep -v 'bibliography' > _warnings || echo "no spelling errors!"
     - grep -P -n "[^[:ascii:]]" mef/* | grep -v 'bibliography' >> _warnings || echo "no non-ASCII chars!"
     - make latexpdf > /dev/null || echo "Outdated LaTeX on Ubuntu 14.04 :("