Change equality assertion to tm.assert_frame_equal

In line with (pandas-dev#44803).

Author: NumberPiOso

pandas/tests/groupby/test_groupby.py

@@ -43,7 +43,7 @@ def test_group_by_copy():
 
     grp_by_same_value = df.groupby(["age"]).apply(lambda group: group)
     grp_by_copy = df.groupby(["age"]).apply(lambda group: group.copy())
-    assert grp_by_same_value == grp_by_copy
+    tm.assert_frame_equal(grp_by_same_value, grp_by_copy)
 
 
 def test_repr():