diff --git a/tests/run_tests.sh b/tests/run_tests.sh
index 9761585..f4d5df0 100755
--- a/tests/run_tests.sh
+++ b/tests/run_tests.sh
@@ -40,6 +40,7 @@
     virtualenv $VENV_DIR
     source ${VENV_DIR}/bin/activate
     python -m pip install salt${PIP_SALT_VERSION}
+    python -m pip install 'msgpack<1.0.0'
 }
 
 setup_mock_bin() {