BUG pandas-dev#15713 Series.asof return nan when series is all nans.

Author: Carlos Souza

RELEASE.md

@@ -1,6 +1,6 @@
 Release Notes
 =============
 
-The list of changes to Pandas between each release can be found
+The list of changes to pandas between each release can be found
 [here](http://pandas.pydata.org/pandas-docs/stable/whatsnew.html). For full
 details, see the commit logs at http://github.com/pandas-dev/pandas.

pandas/indexes/base.py

@@ -1890,7 +1890,6 @@ def asof_locs(self, where, mask):
         locs = self.values[mask].searchsorted(where.values, side='right')
 
         locs = np.where(locs > 0, locs - 1, 0)
-
         result = np.arange(len(self))[mask].take(locs)
 
         first = mask.argmax()

pandas/tests/series/test_asof.py

@@ -153,8 +153,6 @@ def test_errors(self):
 
         # series is all nans
         result = Series([np.nan]).asof([0])
-
         expected = Series([np.nan])
-
         assert_series_equal(result, expected)