diff --git a/test/run_all.sh b/test/run_all.sh
index 4884c81f..b0dddbd4 100755
--- a/test/run_all.sh
+++ b/test/run_all.sh
@@ -24,7 +24,7 @@ check_test_status() {
 # Overwrite assert.sh _assert_cleanup trap with our own
 trap check_test_status EXIT
 
-TESTS=*_test.sh
+TESTS="${@:-*_test.sh}"
 
 # If running on circle, use the scheduler to work out what tests to run
 if [ -n "$CIRCLECI" ]; then