add test for no usable non-default attributes

python-attrs · Nov 18, 2020 · 25ffce7 · 25ffce7
1 parent 1efd738
commit 25ffce7
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Showing 2 changed files with 15 additions and 1 deletion.
diff --git a/src/cattr/disambiguators.py b/src/cattr/disambiguators.py
@@ -48,7 +48,7 @@ def create_uniq_field_dis_func(*classes: Type) -> Callable:
                 if getattr(cl_fields, attr_name).default is NOTHING:
                     break
             else:
-                raise Exception(f"{cl} has no usable non-default attributes.")
+                raise ValueError(f"{cl} has no usable non-default attributes.")
             uniq_attrs_dict[attr_name] = cl
         else:
             fallback = cl

diff --git a/tests/test_disambigutors.py b/tests/test_disambigutors.py
@@ -1,4 +1,6 @@
 """Tests for auto-disambiguators."""
+from typing import Any
+
 import attr
 import pytest
 
@@ -41,6 +43,18 @@ class D(object):
         # No unique fields on either class.
         create_uniq_field_dis_func(C, D)
 
+    @attr.s
+    class E:
+        pass
+
+    @attr.s
+    class F:
+        b = attr.ib(default=Any)
+
+    with pytest.raises(ValueError):
+        # no usable non-default attributes
+        create_uniq_field_dis_func(E, F)
+
 
 @given(simple_classes(defaults=False))
 def test_fallback(cl_and_vals):