update as recommended

Author: thoo

pandas/tests/extension/base/methods.py

@@ -112,8 +112,7 @@ def test_fillna_copy_frame(self, data_missing):
         filled_val = df.iloc[0, 0]
         result = df.fillna(filled_val)
 
-        assert df.values.base is not result.values.base
-        assert df.A._values is arr
+        assert df.A.values is not result.A.values
 
     def test_fillna_copy_series(self, data_missing):
         arr = data_missing.take([1, 1])