Fixes from unit testing

I've made a few fixes:
* corrected a typo in get_marshamallow_plugin (extra a).
* fixed field2property so it doesn't return
  empty dictionaries for simple types
* Added new cases to ensure_schema so it won't
  fail if given a class.

Author: rwb27

src/labthings/apispec/plugins.py

@@ -11,7 +11,7 @@
 from ..schema import ActionSchema, EventSchema
 from ..utilities import get_docstring, get_summary, merge
 from ..views import ActionView, EventView, PropertyView, View
-from .utilities import ensure_schema, get_marshamallow_plugin
+from .utilities import ensure_schema, get_marshmallow_plugin
 
 
 class ExtendedOpenAPIConverter(OpenAPIConverter):
@@ -166,7 +166,7 @@ def spec_for_action(self, action):
             # It would be neater to combine the schemas in OpenAPI with allOf
             # I think the code below does it - but I'm not yet convinced it is working
             # TODO: add tests to validate this
-            plugin = get_marshamallow_plugin(self.spec)
+            plugin = get_marshmallow_plugin(self.spec)
             action_input_dict = (
                 plugin.resolver.resolve_schema_dict(action_input)
                 if action_input

src/labthings/apispec/utilities.py

@@ -1,3 +1,4 @@
+from inspect import isclass
 from typing import Dict, Union
 
 from apispec.ext.marshmallow import MarshmallowPlugin
@@ -11,29 +12,42 @@ def field2property(field):
     """Convert a marshmallow Field to OpenAPI dictionary"""
     converter = FieldConverterMixin()
     converter.init_attribute_functions()
-    return converter.field2pattern(field)
+    return converter.field2property(field)
 
 
 def ensure_schema(
     schema: Union[fields.Field, Schema, Dict[str, Union[fields.Field, type]]],
     name: str = "GeneratedFromDict",
 ) -> Union[dict, Schema]:
-    """Create a Schema object, or OpenAPI dictionary, given a Field, Schema, or Dict."""
+    """Create a Schema object, or OpenAPI dictionary, given a Field, Schema, or Dict.
+
+    The output from this function should be suitable to include in a dictionary
+    that is passed to APISpec.  Fields won't get processed by the Marshmallow
+    plugin, and can't be converted to Schemas without adding a field name, so
+    we convert them directly to the dictionary representation.
+
+    Other Schemas are returned as Marshmallow Schema instances, which will be
+    converted to references by the plugin.
+    """
     if schema is None:
         return None
     if isinstance(schema, fields.Field):
         return field2property(schema)
+    if isclass(schema) and issubclass(schema, fields.Field):
+        return field2property(schema())
     elif isinstance(schema, dict):
         return Schema.from_dict(schema, name=name)()
     elif isinstance(schema, Schema):
         return schema
+    elif isclass(schema) and issubclass(schema, Schema):
+        return schema()
     else:
         raise TypeError(
             f"Invalid schema type {type(schema)}. Must be a Schema or Mapping/dict"
         )
 
 
-def get_marshamallow_plugin(spec):
+def get_marshmallow_plugin(spec):
     """Extract the marshmallow plugin object from an APISpec"""
     for p in spec.plugins:
         if isinstance(p, MarshmallowPlugin):