added a test for cmdline function

Author: chrispycheng

nibabel/tests/test_scripts.py

@@ -69,6 +69,16 @@ def check_nib_ls_example4d(opts=[], hdrs_str="", other_str=""):
 
 
 def check_nib_diff_examples():
+    fnames = [pjoin(DATA_PATH, f)
+               for f in ('standard.nii.gz', 'example4d.nii.gz')]
+    code, stdout, stderr = run_command(['nib-diff'] + fnames, check_code=False)
+    checked_fields = ["Field", "regular", "dim_info", "dim", "datatype", "bitpix", "pixdim", "slice_end",
+                      "xyzt_units", "cal_max", "descrip", "qform_code", "sform_code", "quatern_b",
+                      "quatern_c", "quatern_d", "qoffset_x", "qoffset_y", "qoffset_z", "srow_x",
+                      "srow_y", "srow_z"]
+    for item in checked_fields:
+        assert_true(item in stdout)
+
     fnames2 = [pjoin(DATA_PATH, f)
               for f in ('example4d.nii.gz', 'example4d.nii.gz')]
     code, stdout, stderr = run_command(['nib-diff'] + fnames2, check_code=False)