raise error for collections without queryables (#1757)

pygeoapi/api/itemtypes.py

@@ -134,6 +134,12 @@ def get_collection_queryables(api: API, request: Union[APIRequest, Any],
             LOGGER.debug('Loading record provider')
             p = load_plugin('provider', get_provider_by_type(
                 api.config['resources'][dataset]['providers'], 'record'))
+        finally:
+            msg = 'queryables not available for this collection'
+            return api.get_exception(
+                HTTPStatus.BAD_REQUEST, headers, request.format,
+                'NoApplicableError', msg)
+
     except ProviderGenericError as err:
         return api.get_exception(
             err.http_status_code, headers, request.format,

tests/api/test_itemtypes.py

@@ -62,6 +62,11 @@ def test_get_collection_queryables(config, api_):
         api_, req, 'notfound')
     assert code == HTTPStatus.NOT_FOUND
 
+    req = mock_api_request()
+    rsp_headers, code, response = get_collection_queryables(
+        api_, req, 'mapserver_world_map')
+    assert code == HTTPStatus.BAD_REQUEST
+
     req = mock_api_request({'f': 'html'})
     rsp_headers, code, response = get_collection_queryables(api_, req, 'obs')
     assert rsp_headers['Content-Type'] == FORMAT_TYPES[F_HTML]