Revise the doc, refactor test case and remove the incorrect if condition.

Signed-off-by: HE, Tao <[email protected]>

Author: sighingnow

doc/source/whatsnew/v0.25.0.rst

@@ -122,8 +122,7 @@ Bug Fixes
 ~~~~~~~~~
 - Bug in :func:`to_datetime` which would raise an (incorrect) ``ValueError`` when called with a date far into the future and the ``format`` argument specified instead of raising ``OutOfBoundsDatetime`` (:issue:`23830`)
 - Bug in an error message in :meth:`DataFrame.plot`. Improved the error message if non-numerics are passed to :meth:`DataFrame.plot` (:issue:`25481`)
-- Fixed bug in :meth:`Series.divmod` and :meth:`Series.rdivmod` (:issue:`25557`)
--
+- Bug in :meth:`Series.divmod` and :meth:`Series.rdivmod` which would raise an (incorrect) ``ValueError`` rather than return a pair of :class:`Series` object as result (:issue:`25557`)
 
 Categorical
 ^^^^^^^^^^^

pandas/core/ops.py

@@ -1661,8 +1661,7 @@ def _construct_result(left, result, index, name, dtype=None):
     """
     out = left._constructor(result, index=index, dtype=dtype)
     out.__finalize__(left)
-    if name is None:
-        out.name = name
+    out.name = name
     return out
 
 

pandas/tests/series/test_operators.py

@@ -746,15 +746,15 @@ def test_divmod(self):
         a = Series([1, 1, 1, np.nan], index=['a', 'b', 'c', 'd'])
         b = Series([2, np.nan, 1, np.nan], index=['a', 'b', 'd', 'e'])
 
-        r1 = divmod(a, b)
-        r2 = a.divmod(b)
-        assert_series_equal(r1[0], r2[0])
-        assert_series_equal(r1[1], r2[1])
-
-        r3 = divmod(b, a)
-        r4 = a.rdivmod(b)
-        assert_series_equal(r3[0], r4[0])
-        assert_series_equal(r3[1], r4[1])
+        result = a.divmod(b)
+        expected = divmod(a, b)
+        assert_series_equal(result[0], expected[0])
+        assert_series_equal(result[1], expected[1])
+
+        result = a.rdivmod(b)
+        expected = divmod(b, a)
+        assert_series_equal(result[0], expected[0])
+        assert_series_equal(result[1], expected[1])
 
 
 class TestSeriesUnaryOps(object):