pytest-arraydiff is a py.test plugin to facilitate the generation and comparison
of data arrays produced during tests, in particular in cases where the arrays
are too large to conveniently hard-code them in the tests
(e.g. np.testing.assert_allclose(x, [1, 2, 3])).

The basic idea is that you can write a test that generates a Numpy array (or
other related objects depending on the format, e.g. pandas DataFrame). You can
then either run the tests in a mode to generate reference files from the arrays,
or you can run the tests in comparison mode, which will compare the results of
the tests to the reference ones within some tolerance.

At the moment, the supported file formats for the reference files are:
* A plain text-based format (based on Numpy loadtxt output)
* The FITS format (requires astropy). With this format, tests can return either
  a Numpy array for a FITS HDU object.
* A pandas HDF5 format using the pandas HDFStore