Improve error handling of ESAP-DB server responses.

esap_client/helpers.py

 """This module provides helper functions for the ESAP client."""
-from typing import Type
+import json
+from typing import Any, Type
 
 from requests import Response
 from tabulate import tabulate
@@ -18,7 +19,12 @@ def raise_for_status(response: Response) -> None:
     else:
         cls = ESAPServerError
 
+    error: Any
+    try:
         error = response.json()
+    except json.JSONDecodeError:
+        error = response.text
+
     if isinstance(error, dict) and 'detail' in error:
         error = error['detail']
     raise cls(f'HTTP Error {response.status_code}: {error}')

esap_client/models/collections.py

@@ -19,7 +19,7 @@ def __init__(self, api: str, resource_cls: Type[T]) -> None:
         """The `ResourceCollection` constructor."""
         self.session = BasedSession(api)
         self.deserialize: Callable[[dict], T] = resource_cls.deserialize
-        self.resource_type = type(resource_cls).__name__
+        self.resource_type = resource_cls.__name__.lower()
 
     def __iter__(self) -> Iterator[T]:
         """Iterates through the resources in the collection."""