diff --git a/.travis.yml b/.travis.yml
index 0336fdd..a2d8f2c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -12,7 +12,7 @@ before_install:
 install:
 - ansible-playbook --extra-vars="brozzler_pip_name=file://$TRAVIS_BUILD_DIR#egg=brozzler user=travis" --inventory-file=ansible/hosts-localhost ansible/playbook.yml
 - head -999 /etc/service/*/run
-- pip install $TRAVIS_BUILD_DIR git+https://github.com/internetarchive/warcprox.git#egg=warcprox pytest
+- pip install $TRAVIS_BUILD_DIR git+https://github.com/internetarchive/warcprox.git#egg=warcprox pytest==4.3.0
 - chromium-browser --version
 - sudo apt-get update
 - sudo apt-get install --only-upgrade chromium-browser
diff --git a/vagrant/run-tests.sh b/vagrant/run-tests.sh
index b1ff00b..2d6c117 100755
--- a/vagrant/run-tests.sh
+++ b/vagrant/run-tests.sh
@@ -17,5 +17,5 @@ vagrant ssh -- 'sudo svstat /etc/service/warcprox ;
                 sudo svstat /etc/service/vnc-websock'
 echo
 
-vagrant ssh -- 'set -x ; source /opt/brozzler-ve3/bin/activate && pip install pytest && pip install --upgrade --pre "warcprox>=2.1b1.dev86"'
-vagrant ssh -- "source /opt/brozzler-ve3/bin/activate && DISPLAY=:1 py.test -v /brozzler/tests $@"
+vagrant ssh -- 'set -x ; source /opt/brozzler-ve3/bin/activate && pip install pytest==4.3.0 && pip install --upgrade --pre "warcprox>=2.1b1.dev86"'
+vagrant ssh -- "source /opt/brozzler-ve3/bin/activate && DISPLAY=:1 py.test --tb=native -v /brozzler/tests $@"