old_contents: 
  from dipy.io.utils import decfa
  from nibabel import Nifti1Image
  import numpy as np
  
  def test_decfa():
      data_orig = np.zeros((4, 4, 4, 3))
      data_orig[0, 0, 0] = np.array([1, 0, 0])
      img_orig = Nifti1Image(data_orig, np.eye(4))
      img_new = decfa(img_orig)
      data_new = img_new.get_data()
      assert data_new[0, 0, 0] = (1, 0, 0)
new_contents: from dipy.io.utils import decfa
  from nibabel import Nifti1Image
  import numpy as np
  
  def test_decfa():
      data_orig = np.zeros((4, 4, 4, 3))
      data_orig[0, 0, 0] = np.array([1, 0, 0])
      img_orig = Nifti1Image(data_orig, np.eye(4))
      img_new = decfa(img_orig)
      data_new = img_new.get_data()
      assert data_new[0, 0, 0] == (1, 0, 0)
      assert data_new.dtype ==  np.dtype([('R', 'uint8'), ('G', 'uint8'), ('B', 'uint8')])
subject: Test properly, including the dtype.