Allow empty string in auth (#283)

* Allow empty string in auth

* @grahamalama review

* Raise ValueError only if not empty

Author: leplatrem

CHANGELOG.rst

@@ -7,7 +7,9 @@ This document describes changes between each past release.
 10.11.0 (unreleased)
 ====================
 
-- Nothing changed yet.
+**Bug fixes**
+
+- Fix breaking change introduced in previous version, accept empty string in ``auth`` parameter
 
 
 10.10.0 (2022-06-27)

kinto_http/session.py

@@ -33,14 +33,14 @@ def create_session(server_url=None, auth=None, session=None, **kwargs):
         msg = "You need to either set session or auth + server_url"
         raise AttributeError(msg)
 
-    if auth is not None and isinstance(auth, str):
+    if isinstance(auth, str):
         if ":" in auth:
             auth = tuple(auth.split(":", 1))
         elif "bearer" in auth.lower():
             # eg, "Bearer ghruhgrwyhg"
             _type, token = auth.split(" ", 1)
             auth = kinto_http.BearerTokenAuth(token, type=_type)
-        else:
+        elif auth:  # not empty
             raise ValueError(
                 "Unsupported `auth` parameter value. Must be a tuple() or string "
                 "in the form of `user:pass` or `Bearer xyz`"

kinto_http/tests/test_session.py

@@ -227,6 +227,11 @@ def test_auth_can_be_passed_as_basic_header(session_setup: Tuple[MagicMock, Sess
     assert session.auth.token == "abcdef"
 
 
+def test_auth_cannot_be_an_empty_string(session_setup: Tuple[MagicMock, Session]):
+    session = create_session(auth="")
+    assert session.auth == ""
+
+
 def test_auth_cannot_be_an_arbitrary_string(session_setup: Tuple[MagicMock, Session]):
     with pytest.raises(ValueError) as exc:
         create_session(auth="Some abcdef")