ERROR: test_argmin_argmax (pandas.tseries.tests.test_timeseries.TestDatetimeIndex)
```

Traceback (most recent call last):
  File "/home/agerigk/python-packages/pandas/pandas/tseries/tests/test_timeseries.py", line 1106, in test_argmin_argmax
    self.assertEqual(idx.argmin(), 1)
  File "/home/agerigk/python-packages/pandas/pandas/tseries/index.py", line 1041, in argmin
    return (-self).argmax()
TypeError: ufunc 'negative' did not contain a loop with signature matching types dtype('<M8[ns]') dtype('<M8[ns]')

----------------------------------------------------------------------
Ran 2037 tests in 23.856s

FAILED (SKIP=46, errors=1)
```
