Fix error in hncc_dnb composite test

[djhoese]

Pull requests started failing on travis with the following error:

 File "/home/travis/build/pytroll/satpy/satpy/composites/viirs.py", line 1069, in _gain_factor
    gain[mask] = (58 + 4 / np.cos(np.deg2rad(theta[mask]))) / 5
IndexError: too many indices for array

This PR should fix this, although on my machine I got a different error for the same line of code.

• Tests added and test suite added to parent suite
• Tests passed
• Passes flake8 satpy

[djhoese]

For the record, on my machine I got:

  File "/Users/davidh/repos/git/satpy/satpy/composites/viirs.py", line 1070, in _gain_factor
    gain[mask] = (58 + 4 / np.cos(np.deg2rad(theta[mask]))) / 5
  File "/Users/davidh/anaconda/envs/satpy_py37/lib/python3.7/site-packages/dask/array/core.py", line 1404, in __setitem__
    y = where(key, value, self)
  File "/Users/davidh/anaconda/envs/satpy_py37/lib/python3.7/site-packages/dask/array/routines.py", line 1223, in where
    return elemwise(np.where, condition, x, y)
  File "/Users/davidh/anaconda/envs/satpy_py37/lib/python3.7/site-packages/dask/array/core.py", line 3723, in elemwise
    broadcast_shapes(*shapes)
  File "/Users/davidh/anaconda/envs/satpy_py37/lib/python3.7/site-packages/dask/array/core.py", line 3684, in broadcast_shapes
    "shapes {0}".format(" ".join(map(str, shapes)))
ValueError: operands could not be broadcast together with shapes (5, 10) (nan,) (5, 10)

[mraspaud]

Thanks for fixing this. I see this is still failing, is there anything more we can do about it ?

[djhoese]

I'm restarting all the travis jobs. I'm still actively working with the ci-helpers people to fix things when using the new versions of conda. We are really close to getting stuff done, but most of the maintainers of that project don't have a lot of time this week.

My summary of working on ci-helpers: It has been long over due that it gets updated for modern conda/python/etc.