diff --git a/src/testdir/test_channel.py b/src/testdir/test_channel.py
index 227780a..b5a912c 100644
--- a/src/testdir/test_channel.py
+++ b/src/testdir/test_channel.py
@@ -73,6 +73,11 @@
                         print("sending: {0}".format(cmd))
                         self.request.sendall(cmd.encode('utf-8'))
                         response = "ok"
+                    elif decoded[1] == 'bad command':
+                        cmd = '["ex","foo bar"]'
+                        print("sending: {0}".format(cmd))
+                        self.request.sendall(cmd.encode('utf-8'))
+                        response = "ok"
                     elif decoded[1] == 'do normal':
                         # Send a normal command.
                         cmd = '["normal","G$s more\u001b"]'