diff --git a/support/testing/infra/basetest.py b/support/testing/infra/basetest.py
index 12d96415da..5c3231d2b9 100644
--- a/support/testing/infra/basetest.py
+++ b/support/testing/infra/basetest.py
@@ -91,3 +91,14 @@ class BRTest(BRConfigTest):
             0,
             "\nFailed to run: {}\noutput was:\n{}".format(cmd, '  '+'\n  '.join(out))
         )
+
+    # Run the given 'cmd' with a 'timeout' on the target and
+    # assert that the command fails; on success, print the
+    # faulty command and its output
+    def assertRunNotOk(self, cmd, timeout=-1):
+        out, exit_code = self.emulator.run(cmd, timeout)
+        self.assertNotEqual(
+            exit_code,
+            0,
+            "\nUnexpected success: {}\noutput was:\n{}".format(cmd, '  '+'\n  '.join(out))
+        )