fixing up github test

Author: tclose

tests/test_github.py

@@ -1,14 +1,15 @@
 import pytest
+import nibabel as nb
+import numpy as np
 from medimages4tests.utils import retrieve_from_github
-from fileformats.medimage import NiftiGz
 
 
 @pytest.mark.xfail
 def test_github_retrieve():
 
-    path = retrieve_from_github(
+    nifti_fpath = retrieve_from_github(
         org="nipype", repo="pydra-fsl-testdata", path="melodic_ica"
     )
-    nifti = NiftiGz(path)
+    nifti = nifti = nb.load(nifti_fpath)
 
-    assert nifti.shape == (204, 256, 256)
+    assert np.array_equal(nifti.header["dim"][:4], [3, 204, 256, 256])