add test case for df copy=True

Author: jorisvandenbossche

pandas/tests/copy_view/test_array.py

@@ -141,6 +141,17 @@ def test_dataframe_multiple_numpy_dtypes():
     with pytest.raises(ValueError, match="Unable to avoid copy while creating"):
         arr = np.array(df, copy=False)
 
+    arr = np.array(df, copy=True)
+    assert arr.flags.writeable is True
+
+
+def test_dataframe_single_block_copy_true():
+    # the copy=False/None cases are tested above in test_dataframe_values
+    df = DataFrame({"a": [1, 2, 3], "b": [4, 5, 6]})
+    arr = np.array(df, copy=True)
+    assert not np.shares_memory(arr, get_array(df, "a"))
+    assert arr.flags.writeable is True
+
 
 def test_values_is_ea():
     df = DataFrame({"a": date_range("2012-01-01", periods=3)})