issue_comments: 147142725

I'm actually going to paste the traceback from one of the test results (using py.test) to show how nonsensical this is:

``` =========================================================================================================== FAILURES ============================================================================================================ _____________ TestVariable.test_index_0d_not_a_time _____________

self = <xray.test.test_variable.TestVariable testMethod=test_index_0d_not_a_time>

def test_index_0d_not_a_time(self):
    d = np.datetime64('NaT')
    x = self.cls(['x'], [d])
    # Wasn't able to figure out why this was failing.
    # AssertionError: numpy.datetime64('NaT') != numpy.datetime64('NaT')

  self.assertIndexedLikeNDArray(x, d, None)

xray/test/test_variable.py:115:

xray/test/test_variable.py:61: in assertIndexedLikeNDArray self.assertEqual(variable.values[0], expected_value0)

self = <xray.test.test_variable.TestVariable testMethod=test_index_0d_not_a_time>, a1 = numpy.datetime64('NaT'), a2 = numpy.datetime64('NaT')

def assertEqual(self, a1, a2):

  assert a1 == a2 or (a1 != a1 and a2 != a2)

E AssertionError: assert (numpy.datetime64('NaT') == numpy.datetime64('NaT') or (numpy.datetime64('NaT') != numpy.datetime64('NaT')))

xray/test/init.py:154: AssertionError ```

I don't get how neither of these are true:

(numpy.datetime64('NaT') == numpy.datetime64('NaT') or\ (numpy.datetime64('NaT') != numpy.datetime64('NaT')))