TST: Add tests for CategoricalIndex mismatch scenarios

Author: Aniketsy

pandas/tests/util/test_assert_index_equal.py

@@ -320,7 +320,7 @@ def test_assert_multi_index_dtype_check_categorical(check_categorical):
 
 
 def test_assert_index_equal_categorical_mismatch_categories():
-    # GH#61941
+    # GH#61941 - CategoricalIndex vs Index
     ci = CategoricalIndex(["a", "b", "c"], categories=["a", "b", "c"], ordered=False)
     idx = Index(["a", "b", "c"])
 
@@ -329,3 +329,15 @@ def test_assert_index_equal_categorical_mismatch_categories():
             ci,
             idx,
         )
+
+
+def test_assert_categorical_index_equal_mismatch_categories():
+    # GH#61941 - both left and right are CategoricalIndex
+    ci1 = CategoricalIndex(["a", "b", "c"], categories=["a", "b", "c"], ordered=False)
+    ci2 = CategoricalIndex(["a", "b", "c"], categories=["a", "b", "d"], ordered=False)
+
+    with pytest.raises(AssertionError, match="Index are different"):
+        tm.assert_index_equal(
+            ci1,
+            ci2,
+        )