new_contents: '''Unit tests for Aronnax'''
  
  from contextlib import contextmanager
  import os.path as p
  import re
  
  import numpy as np
  from scipy.io import FortranFile
  
  import aronnax as aro
  from aronnax.utils import working_directory
  
  import pytest
  import glob
  
  self_path = p.dirname(p.abspath(__file__))
  
  def test_open_mfdataarray():
      '''Open a number of files and assert that the length of the time
          dimension is the same as the number of files.'''
      
      xlen = 1e6
      ylen = 2e6
      nx = 10; ny = 20
      layers = 1
      grid = aro.Grid(nx, ny, layers, xlen / nx, ylen / ny)
  
      with working_directory(p.join(self_path, "beta_plane_gyre_red_grav")):
          output_files = glob.glob('output/snap.h*')
          ds = aro.open_mfdataarray(output_files, grid)
  
          assert len(output_files) == ds.time.shape[0]
  
      
  
  def test_open_mfdataarray_multiple_variables():
      '''This test tries to open multiple different variables in the same call,
          and should fail.'''
      
      xlen = 1e6
      ylen = 2e6
      nx = 10; ny = 20
      layers = 1
      grid = aro.Grid(nx, ny, layers, xlen / nx, ylen / ny)
  
      with working_directory(p.join(self_path, "beta_plane_gyre_red_grav")):
          with pytest.raises(Exception):
              output_files = glob.glob('output/snap.*')
              ds = aro.open_mfdataarray(output_files, grid)
              
subject: Test for new function for reading output