TST: Added test for consistent type with unique agg pandas-dev#22558

Author: KingOfTheShow69

pandas/tests/groupby/aggregate/test_aggregate.py

@@ -1438,3 +1438,15 @@ def test_agg_of_mode_list(test, constant):
     expected = expected.set_index(0)
 
     tm.assert_frame_equal(result, expected)
+
+
+def test_unique_agg_type():
+    # GH#22558
+    df1 = DataFrame({"a": [1, 2, 3], "b": [1, 1, 1]})
+    df2 = DataFrame({"a": [2, 2, 2], "b": [1, 1, 1]})
+    aggregation = {"a": "unique", "b": "unique"}
+
+    agg1 = df1.agg(aggregation)
+    agg2 = df2.agg(aggregation)
+
+    tm.assert_class_equal(agg1, agg2)