Error on duplicate WizardObjectPlugins

Author: dwhswenson

paths_cli/tests/wizard/test_plugin_classes.py

@@ -290,9 +290,12 @@ def test_register_plugin(self):
         self.wrapper.register_plugin(self.plugin_no_format)
         assert len(self.wrapper.choices) == 1
         assert self.wrapper.choices['bar'] == self.plugin_no_format
-        # TODO: what is the desired behavior if more that one plugin tries
-        # to register with the same name? override or error? currently
-        # overrides, but that should not be considered API
+
+    def test_register_plugin_duplicate(self):
+        self.wrapper.choices['bar'] = self.plugin_no_format
+        with pytest.raises(WizardObjectPluginRegistrationError,
+                           match="already been registered"):
+            self.wrapper.register_plugin(self.plugin_format)
 
     @pytest.mark.parametrize('input_type', ['method', 'format', 'string'])
     def test_get_ask(self, input_type):

paths_cli/wizard/plugin_classes.py

@@ -5,6 +5,11 @@
 from paths_cli.wizard.parameters import WizardParameter
 from paths_cli.wizard.helper import Helper
 
+
+class WizardObjectPluginRegistrationError(Exception):
+    pass
+
+
 _PLUGIN_DOCSTRING = """
     requires_ops : Tuple[int, int]
         version of OpenPathSampling required for this plugin
@@ -360,6 +365,11 @@ def register_plugin(self, plugin):
         plugin : :class:`.WizardObjectPlugin`
             the plugin to register
         """
+        if plugin.name in self.choices:
+            raise WizardObjectPluginRegistrationError(
+                f"A plugin named '{plugin.name}' has already been "
+                f"registered with the category '{self.name}'"
+            )
         self.choices[plugin.name] = plugin
 
     def _get_intro(self, wizard, context):