Ensure the constructor works with unhashable objects

Author: kaste

mockito/inorder.py

@@ -19,7 +19,7 @@
 # THE SOFTWARE.
 from __future__ import annotations
 
-from collections import Counter, deque
+from collections import deque
 from functools import partial
 from typing import Deque
 
@@ -41,14 +41,12 @@ def verify(object, *args, **kwargs):
 class InOrder:
 
     def __init__(self, *objects: object):
-        counter = Counter(objects)
-        duplicates = [d for d, freq in counter.items() if freq > 1]
-        if duplicates:
-            raise ValueError(
-                f"\nThe following Mocks are duplicated: "
-                f"{[str(d) for d in duplicates]}"
-            )
-        self._objects = objects
+        objects_ = []
+        for obj in objects:
+            if obj in objects_:
+                raise ValueError(f"{obj} is provided more than once")
+            objects_.append(obj)
+        self._objects = objects_
         self._attach_all()
         self.ordered_invocations: Deque[RealInvocation] = deque()
 

tests/in_order_test.py

@@ -17,8 +17,14 @@ def test_observing_the_same_mock_twice_should_raise():
     a = mock()
     with pytest.raises(ValueError) as e:
         InOrder(a, a)
-    assert str(e.value) == ("\nThe following Mocks are duplicated: "
-                            f"['{a}']")
+    assert str(e.value) == f"{a} is provided more than once"
+
+
+def test_observing_the_same_mock_twice_should_raise_unhashable_obj():
+    a = dict()  # type: ignore[var-annotated]
+    with pytest.raises(ValueError):
+        InOrder(a, a)
+
 
 def test_correct_order_declaration_should_pass():
     cat = mock()