[bugfix] Fix script_tests failing assert

Change-Id: I44ee792ece5cd2c4cc721cb0fe094df98906d8f7
---
M tests/script_tests.py
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/script_tests.py b/tests/script_tests.py
index cd85361..dac48de 100644
--- a/tests/script_tests.py
+++ b/tests/script_tests.py
@@ -297,7 +297,7 @@
                     if stdout is not None and out_result:
                         self.assertIn(stdout, out_result)
                     else:
-                        self.assertIsNone(out_result)
+                        self.assertIsEmpty(out_result)
 
                 self.assertIn(result['exit_code'], exit_codes)
                 sys.stdout.flush()

