pydata/pandas — pull request #5524 by commonlisp (2013-11-15 16:31:06+00:00)
Title: BUG/TST: Fixes isnull behavior on NaT in array. Closes #5443

I added a test case test_isnull_nat() to test_common.py and a check for NaT in lib.isnullobj. pd.isnull(np.array([pd.NaT])) now yields the correct results ([True]).