Handling case when completekey is empty string.

Author: kmvanbrunt

cmd2/cmd2.py

@@ -370,7 +370,7 @@ def __init__(
     ) -> None:
         """Easy but powerful framework for writing line-oriented command interpreters, extends Python's cmd package.
 
-        :param completekey: name of a completion key, default to Tab
+        :param completekey: name of a completion key, default to 'tab'. (If None or an empty string, 'tab' is used)
         :param stdin: alternate input file object, if not specified, sys.stdin is used
         :param stdout: alternate output file object, if not specified, sys.stdout is used
         :param allow_cli_args: if ``True``, then [cmd2.Cmd.__init__][] will process command
@@ -430,7 +430,7 @@ def __init__(
         self.prompt: str = self.DEFAULT_PROMPT
         self.intro = intro
 
-        if completekey is None:
+        if not completekey:
             completekey = self.DEFAULT_COMPLETEKEY
 
         # What to use for standard input

tests/test_cmd2.py

@@ -4164,6 +4164,17 @@ def test_custom_completekey_ctrl_k():
     assert found, "Could not find binding for 'c-k' (Keys.ControlK) in session key bindings"
 
 
+def test_completekey_empty_string() -> None:
+    # Test that an empty string for completekey defaults to DEFAULT_COMPLETEKEY
+    with mock.patch('cmd2.Cmd._create_main_session', autospec=True) as create_session_mock:
+        create_session_mock.return_value = mock.MagicMock(spec=PromptSession)
+        app = cmd2.Cmd(completekey='')
+
+        # Verify it was called with DEFAULT_COMPLETEKEY
+        # auto_suggest is the second arg and it defaults to True
+        create_session_mock.assert_called_once_with(app, True, app.DEFAULT_COMPLETEKEY)
+
+
 def test_create_main_session_exception(monkeypatch):
 
     # Mock PromptSession to raise ValueError on first call, then succeed