Edited original merge to be inline with pandas-dev#62869, added 'object' as dtype to be captured in frame:to_series

Author: eicchen

pandas/core/frame.py

@@ -8491,7 +8491,10 @@ def to_series(right):
             # pass dtype to avoid doing inference, which would break consistency
             #  with Index/Series ops
             dtype = None
-            if getattr(right, "dtype", None) == object:
+            if (
+                getattr(right, "dtype", None) == "object"
+                or getattr(right, "dtype", None) == object
+            ):
                 # can't pass right.dtype unconditionally as that would break on e.g.
                 #  datetime64[h] ndarray
                 dtype = object

pandas/tests/arithmetic/test_string.py

@@ -244,9 +244,6 @@ def test_mul(any_string_dtype):
 
 def test_add_strings(any_string_dtype, request):
     dtype = any_string_dtype
-    if dtype != np.dtype(object):
-        mark = pytest.mark.xfail(reason="GH-28527")
-        request.applymarker(mark)
     arr = pd.array(["a", "b", "c", "d"], dtype=dtype)
     df = pd.DataFrame([["t", "y", "v", "w"]], dtype=object)
     assert arr.__add__(df) is NotImplemented
@@ -261,10 +258,15 @@ def test_add_strings(any_string_dtype, request):
 
 
 @pytest.mark.xfail(reason="GH-28527")
-def test_add_frame(dtype):
+def test_add_frame(request, dtype):
+    if dtype.storage == "python":
+        # Inconsistent behavior between different versions of the python engine.
+        # Some return correctly, some return but with the wrong dtype
+        # Others just fail, we are blanket failing all
+        mark = pytest.mark.xfail(reason="[XPASS(strict)] GH-28527")
+        request.node.applymarker(mark)
     arr = pd.array(["a", "b", np.nan, np.nan], dtype=dtype)
     df = pd.DataFrame([["x", np.nan, "y", np.nan]])
-
     assert arr.__add__(df) is NotImplemented
 
     result = arr + df

pandas/tests/arrays/string_/test_string.py

@@ -159,113 +159,6 @@ def test_astype_roundtrip(dtype):
     tm.assert_series_equal(result2, ser2)
 
 
-def test_add(dtype):
-    a = pd.Series(["a", "b", "c", None, None], dtype=dtype)
-    b = pd.Series(["x", "y", None, "z", None], dtype=dtype)
-
-    result = a + b
-    expected = pd.Series(["ax", "by", None, None, None], dtype=dtype)
-    tm.assert_series_equal(result, expected)
-
-    result = a.add(b)
-    tm.assert_series_equal(result, expected)
-
-    result = a.radd(b)
-    expected = pd.Series(["xa", "yb", None, None, None], dtype=dtype)
-    tm.assert_series_equal(result, expected)
-
-    result = a.add(b, fill_value="-")
-    expected = pd.Series(["ax", "by", "c-", "-z", None], dtype=dtype)
-    tm.assert_series_equal(result, expected)
-
-
-def test_add_2d(dtype, request):
-    if dtype.storage == "pyarrow":
-        reason = "Failed: DID NOT RAISE <class 'ValueError'>"
-        mark = pytest.mark.xfail(raises=None, reason=reason)
-        request.applymarker(mark)
-
-    a = pd.array(["a", "b", "c"], dtype=dtype)
-    b = np.array([["a", "b", "c"]], dtype=object)
-    with pytest.raises(ValueError, match="3 != 1"):
-        a + b
-
-    s = pd.Series(a)
-    with pytest.raises(ValueError, match="3 != 1"):
-        s + b
-
-
-def test_add_sequence(dtype):
-    a = pd.array(["a", "b", None, None], dtype=dtype)
-    other = ["x", None, "y", None]
-
-    result = a + other
-    expected = pd.array(["ax", None, None, None], dtype=dtype)
-    tm.assert_extension_array_equal(result, expected)
-
-    result = other + a
-    expected = pd.array(["xa", None, None, None], dtype=dtype)
-    tm.assert_extension_array_equal(result, expected)
-
-
-def test_mul(dtype):
-    a = pd.array(["a", "b", None], dtype=dtype)
-    result = a * 2
-    expected = pd.array(["aa", "bb", None], dtype=dtype)
-    tm.assert_extension_array_equal(result, expected)
-
-    result = 2 * a
-    tm.assert_extension_array_equal(result, expected)
-
-
-def test_add_series(dtype):
-    arr = pd.array(["a", "b", "c", "d"], dtype=dtype)
-    ser = pd.Series(["t", "y", "v", "w"], dtype=object)
-
-    result = arr + ser
-    expected = pd.Series(["at", "by", "cv", "dw"]).astype(dtype)
-    tm.assert_series_equal(result, expected)
-
-    result = ser + arr
-    expected = pd.Series(["ta", "yb", "vc", "wd"]).astype(dtype)
-    tm.assert_series_equal(result, expected)
-
-
-def test_add_strings(dtype):
-    arr = pd.array(["a", "b", "c", "d"], dtype=dtype)
-    df = pd.DataFrame([["t", "y", "v", "w"]], dtype=object)
-    assert arr.__add__(df) is NotImplemented
-
-    result = arr + df
-    expected = pd.DataFrame([["at", "by", "cv", "dw"]]).astype(dtype)
-    tm.assert_frame_equal(result, expected)
-
-    result = df + arr
-    expected = pd.DataFrame([["ta", "yb", "vc", "wd"]]).astype(dtype)
-    tm.assert_frame_equal(result, expected)
-
-
-@pytest.mark.xfail(reason="GH-28527")
-def test_add_frame(request, dtype):
-    if dtype.storage == "python":
-        # Inconsistent behavior between different versions of the python engine.
-        # Some return correctly, some return but with the wrong dtype
-        # Others just fail, we are blanket failing all
-        mark = pytest.mark.xfail(reason="[XPASS(strict)] GH-28527")
-        request.node.applymarker(mark)
-    arr = pd.array(["a", "b", np.nan, np.nan], dtype=dtype)
-    df = pd.DataFrame([["x", np.nan, "y", np.nan]])
-    assert arr.__add__(df) is NotImplemented
-
-    result = arr + df
-    expected = pd.DataFrame([["ax", np.nan, np.nan, np.nan]]).astype(dtype)
-    tm.assert_frame_equal(result, expected)
-
-    result = df + arr
-    expected = pd.DataFrame([["xa", np.nan, np.nan, np.nan]]).astype(dtype)
-    tm.assert_frame_equal(result, expected)
-
-
 def test_constructor_raises(cls):
     if cls is pd.arrays.StringArray:
         msg = "StringArray requires a sequence of strings or pandas.NA"