update tests

Author: jorisvandenbossche

pandas/tests/frame/test_arithmetic.py

@@ -11,8 +11,6 @@
 import numpy as np
 import pytest
 
-from pandas._config import using_string_dtype
-
 import pandas as pd
 from pandas import (
     DataFrame,
@@ -2101,12 +2099,21 @@ def test_enum_column_equality():
     tm.assert_series_equal(result, expected)
 
 
-@pytest.mark.xfail(using_string_dtype(), reason="TODO(infer_string)")
-def test_mixed_col_index_dtype():
+def test_mixed_col_index_dtype(any_string_dtype):
     # GH 47382
-    df1 = DataFrame(columns=list("abc"), data=1.0, index=[0])
-    df2 = DataFrame(columns=list("abc"), data=0.0, index=[0])
-    df1.columns = df2.columns.astype("string")
+    df1 = DataFrame(
+        columns=Index(list("abc"), dtype=any_string_dtype), data=1.0, index=[0]
+    )
+    df2 = DataFrame(columns=Index(list("abc"), dtype="object"), data=0.0, index=[0])
+
     result = df1 + df2
-    expected = DataFrame(columns=list("abc"), data=1.0, index=[0])
+    expected = DataFrame(
+        columns=Index(list("abc"), dtype=any_string_dtype), data=1.0, index=[0]
+    )
+    tm.assert_frame_equal(result, expected)
+
+    result = df2 + df1
+    expected = DataFrame(
+        columns=Index(list("abc"), dtype="object"), data=1.0, index=[0]
+    )
     tm.assert_frame_equal(result, expected)

pandas/tests/reshape/test_pivot.py

@@ -2664,6 +2664,8 @@ def test_pivot_columns_not_given(self):
         with pytest.raises(TypeError, match="missing 1 required keyword-only argument"):
             df.pivot()
 
+    # this still fails because columns=None gets passed down to unstack as level=None
+    # while at that point None was converted to NaN
     @pytest.mark.xfail(
         using_string_dtype(), reason="TODO(infer_string) None is cast to NaN"
     )
@@ -2682,10 +2684,7 @@ def test_pivot_columns_is_none(self):
         expected = DataFrame({1: 3}, index=Index([2], name="b"))
         tm.assert_frame_equal(result, expected)
 
-    @pytest.mark.xfail(
-        using_string_dtype(), reason="TODO(infer_string) None is cast to NaN"
-    )
-    def test_pivot_index_is_none(self):
+    def test_pivot_index_is_none(self, using_infer_string):
         # GH#48293
         df = DataFrame({None: [1], "b": 2, "c": 3})
 
@@ -2696,6 +2695,8 @@ def test_pivot_index_is_none(self):
 
         result = df.pivot(columns="b", index=None, values="c")
         expected = DataFrame(3, index=[1], columns=Index([2], name="b"))
+        if using_infer_string:
+            expected.index.name = np.nan
         tm.assert_frame_equal(result, expected)
 
     def test_pivot_values_is_none(self):