diff --git a/tests/run_tests.sh b/tests/run_tests.sh
index ad36e73..29a7975 100755
--- a/tests/run_tests.sh
+++ b/tests/run_tests.sh
@@ -1,3 +1,4 @@
+#! /bin/bash
 RED="\033[31m"
 GREEN="\033[32m"
 YELLOW="\033[33m"