TST: [ArrowStringArray] more parameterised testing - part 3 (#40755)

Author: simonjayhawkins

pandas/tests/io/formats/test_to_csv.py

@@ -204,12 +204,17 @@ def test_to_csv_na_rep(self):
         assert df.set_index("a").to_csv(na_rep="_") == expected
         assert df.set_index(["a", "b"]).to_csv(na_rep="_") == expected
 
-        # GH 29975
-        # Make sure full na_rep shows up when a dtype is provided
         csv = pd.Series(["a", pd.NA, "c"]).to_csv(na_rep="ZZZZZ")
         expected = tm.convert_rows_list_to_csv_str([",0", "0,a", "1,ZZZZZ", "2,c"])
         assert expected == csv
-        csv = pd.Series(["a", pd.NA, "c"], dtype="string").to_csv(na_rep="ZZZZZ")
+
+    def test_to_csv_na_rep_nullable_string(self, nullable_string_dtype):
+        # GH 29975
+        # Make sure full na_rep shows up when a dtype is provided
+        expected = tm.convert_rows_list_to_csv_str([",0", "0,a", "1,ZZZZZ", "2,c"])
+        csv = pd.Series(["a", pd.NA, "c"], dtype=nullable_string_dtype).to_csv(
+            na_rep="ZZZZZ"
+        )
         assert expected == csv
 
     def test_to_csv_date_format(self):

pandas/tests/io/test_parquet.py

@@ -836,6 +836,14 @@ def test_additional_extension_arrays(self, pa):
             expected = df.assign(a=df.a.astype("float64"))
         check_round_trip(df, pa, expected=expected)
 
+    @td.skip_if_no("pyarrow", min_version="1.0.0")
+    def test_pyarrow_backed_string_array(self, pa):
+        # test ArrowStringArray supported through the __arrow_array__ protocol
+        from pandas.core.arrays.string_arrow import ArrowStringDtype  # noqa: F401
+
+        df = pd.DataFrame({"a": pd.Series(["a", None, "c"], dtype="arrow_string")})
+        check_round_trip(df, pa, expected=df)
+
     @td.skip_if_no("pyarrow", min_version="0.16.0")
     def test_additional_extension_types(self, pa):
         # test additional ExtensionArrays that are supported through the

pandas/tests/series/methods/test_convert_dtypes.py

@@ -212,11 +212,11 @@ def test_convert_dtypes(
         # Make sure original not changed
         tm.assert_series_equal(series, copy)
 
-    def test_convert_string_dtype(self):
+    def test_convert_string_dtype(self, nullable_string_dtype):
         # https://github.com/pandas-dev/pandas/issues/31731 -> converting columns
         # that are already string dtype
         df = pd.DataFrame(
-            {"A": ["a", "b", pd.NA], "B": ["ä", "ö", "ü"]}, dtype="string"
+            {"A": ["a", "b", pd.NA], "B": ["ä", "ö", "ü"]}, dtype=nullable_string_dtype
         )
         result = df.convert_dtypes()
         tm.assert_frame_equal(df, result)

pandas/tests/series/methods/test_replace.py

@@ -254,9 +254,9 @@ def test_replace2(self):
         assert (ser[6:10] == -1).all()
         assert (ser[20:30] == -1).all()
 
-    def test_replace_with_dictlike_and_string_dtype(self):
+    def test_replace_with_dictlike_and_string_dtype(self, nullable_string_dtype):
         # GH 32621
-        s = pd.Series(["one", "two", np.nan], dtype="string")
+        s = pd.Series(["one", "two", np.nan], dtype=nullable_string_dtype)
         expected = pd.Series(["1", "2", np.nan])
         result = s.replace({"one": "1", "two": "2"})
         tm.assert_series_equal(expected, result)

pandas/tests/series/test_constructors.py

@@ -1549,10 +1549,12 @@ def test_constructor_datetime64(self):
         series = Series(dates)
         assert np.issubdtype(series.dtype, np.dtype("M8[ns]"))
 
-    def test_constructor_datetimelike_scalar_to_string_dtype(self):
+    def test_constructor_datetimelike_scalar_to_string_dtype(
+        self, nullable_string_dtype
+    ):
         # https://github.com/pandas-dev/pandas/pull/33846
-        result = Series("M", index=[1, 2, 3], dtype="string")
-        expected = Series(["M", "M", "M"], index=[1, 2, 3], dtype="string")
+        result = Series("M", index=[1, 2, 3], dtype=nullable_string_dtype)
+        expected = Series(["M", "M", "M"], index=[1, 2, 3], dtype=nullable_string_dtype)
         tm.assert_series_equal(result, expected)
 
     @pytest.mark.parametrize(