diff --git a/run_tests.sh b/run_tests.sh
index ff5f83ec4e..47a5207d64 100755
--- a/run_tests.sh
+++ b/run_tests.sh
@@ -77,7 +77,7 @@ function run_tests {
   if [ $coverage -eq 1 ]; then
     # Do not test test_coverage_ext when gathering coverage.
     if [ "x$testrargs" = "x" ]; then
-      testrargs = "^(?!.*test_coverage_ext).*$"
+      testrargs="^(?!.*test_coverage_ext).*$"
     fi
     export PYTHON="${wrapper} coverage run --source novaclient --parallel-mode"
   fi