added a functionality test for cmdline access of datatype

Author: chrispycheng

nibabel/cmdline/diff.py

@@ -304,13 +304,12 @@ def diff(files, header_fields='all', data_max_abs_diff=None, data_max_rel_diff=N
     return diff
 
 
-def main(args=None, out=None, dtype=None):
+def main(args=None, out=None):
     """Getting the show on the road"""
 
     out = out or sys.stdout
     parser = get_opt_parser()
     (opts, files) = parser.parse_args(args)
-    dtype = dtype or opts.dtype
 
     nibabel.cmdline.utils.verbose_level = opts.verbose
 
@@ -323,7 +322,7 @@ def main(args=None, out=None, dtype=None):
         header_fields=opts.header_fields,
         data_max_abs_diff=opts.data_max_abs_diff,
         data_max_rel_diff=opts.data_max_rel_diff,
-        dtype=dtype
+        dtype=opts.dtype
     )
 
     if files_diff:

nibabel/tests/test_scripts.py

@@ -95,6 +95,10 @@ def check_nib_diff_examples():
     code, stdout, stderr = run_command(['nib-diff'] + fnames4, check_code=False)
     assert_equal(stdout, "These files are identical.")
 
+    code, stdout, stderr = run_command(['nib-diff', '--dt'] + ['float64'] + fnames, check_code=False)
+    for item in checked_fields:
+        assert_true(item in stdout)
+
 
 
 @script_test