Added unit test for overriding default parser

Author: kmvanbrunt

tests/test_argparse_custom.py

@@ -242,3 +242,20 @@ def test_apcustom_required_options():
     parser = Cmd2ArgumentParser()
     parser.add_argument('--required_flag', required=True)
     assert 'required arguments' in parser.format_help()
+
+
+def test_override_parser():
+    import importlib
+    from cmd2 import DEFAULT_ARGUMENT_PARSER
+
+    # The standard parser is Cmd2ArgumentParser
+    assert DEFAULT_ARGUMENT_PARSER == Cmd2ArgumentParser
+
+    # Set our parser module and force a reload of cmd2 so it loads the module
+    argparse.cmd2_parser_module = 'examples.custom_parser'
+    importlib.reload(cmd2)
+    from cmd2 import DEFAULT_ARGUMENT_PARSER
+
+    # Verify DEFAULT_ARGUMENT_PARSER is now our CustomParser
+    from examples.custom_parser import CustomParser
+    assert DEFAULT_ARGUMENT_PARSER == CustomParser