Move tests to tests/frame/indexing/test_categorical.py

Author: keechongtan

pandas/tests/frame/indexing/test_categorical.py

@@ -354,6 +354,16 @@ def test_functions_no_warnings(self):
                 df.value, range(0, 105, 10), right=False, labels=labels
             )
 
+    def test_setitem_single_row_categorical(self):
+        # GH 25495
+        df = DataFrame({"Alpha": ["a"], "Numeric": [0]})
+        categories = pd.Categorical(df["Alpha"], categories=["a", "b", "c"])
+        df.loc[:, "Alpha"] = categories
+
+        result = df["Alpha"]
+        expected = Series(categories, index=df.index, name="Alpha")
+        tm.assert_series_equal(result, expected)
+
     def test_loc_indexing_preserves_index_category_dtype(self):
         # GH 15166
         df = DataFrame(