diff --git a/.travis.yml b/.travis.yml
index 90c8fb3de7..367fbef5c6 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -453,7 +453,7 @@ script:
     - |
         set -eo pipefail
         if [ "$T" = "coverage" ]; then
-             ./configure --enable-debug --disable-shared --enable-code-coverage
+             ./configure --enable-debug --disable-shared --enable-code-coverage --enable-werror
              make
              make TFLAGS=-n test-nonflaky
              make "TFLAGS=-n -e" test-nonflaky