Always set the canonical version allow_ansi' string value

Author: kmvanbrunt

cmd2/cmd2.py

@@ -563,8 +563,9 @@ def allow_ansi(self) -> str:
 
     @allow_ansi.setter
     def allow_ansi(self, new_val: str) -> None:
-        """Read-only property needed to support do_set when it sets allow_ansi"""
-        if new_val.lower() not in (ansi.ANSI_TERMINAL.lower(), ansi.ANSI_ALWAYS.lower(), ansi.ANSI_NEVER.lower()):
+        """Setter property needed to support do_set when it updates allow_ansi"""
+        new_val = new_val.capitalize()
+        if new_val not in (ansi.ANSI_TERMINAL, ansi.ANSI_ALWAYS, ansi.ANSI_NEVER):
             self.perror('Invalid value: {} (valid values: {}, {}, {})'.format(new_val, ansi.ANSI_TERMINAL,
                                                                               ansi.ANSI_ALWAYS, ansi.ANSI_NEVER))
         else:

tests/test_cmd2.py

@@ -181,18 +181,25 @@ def test_set_quiet(base_app):
     out, err = run_cmd(base_app, 'set quiet')
     assert out == ['quiet: True']
 
-@pytest.mark.parametrize('new_val, is_valid', [
-    (ansi.ANSI_NEVER, False),
-    (ansi.ANSI_TERMINAL, False),
-    (ansi.ANSI_ALWAYS, False),
-    ('neVeR', False),
-    ('TeRMInal', False),
-    ('AlWaYs', False),
-    ('invalid', True),
+@pytest.mark.parametrize('new_val, is_valid, expected', [
+    (ansi.ANSI_NEVER, False, ansi.ANSI_NEVER),
+    ('neVeR', False, ansi.ANSI_NEVER),
+    (ansi.ANSI_TERMINAL, False, ansi.ANSI_TERMINAL),
+    ('TeRMInal', False, ansi.ANSI_TERMINAL),
+    (ansi.ANSI_ALWAYS, False, ansi.ANSI_ALWAYS),
+    ('AlWaYs', False, ansi.ANSI_ALWAYS),
+    ('invalid', True, ansi.ANSI_TERMINAL),
 ])
-def test_set_allow_ansi(base_app, new_val, is_valid):
+def test_set_allow_ansi(base_app, new_val, is_valid, expected):
+    # Initialize allow_ansi for this test
+    ansi.allow_ansi = ansi.ANSI_TERMINAL
+
+    # Use the set command to alter it
     out, err = run_cmd(base_app, 'set allow_ansi {}'.format(new_val))
+
+    # Verify the results
     assert bool(err) == is_valid
+    assert ansi.allow_ansi == expected
 
     # Reload ansi module to reset allow_ansi to its default since it's an
     # application-wide setting that can affect other unit tests.