changes per Yariks comments!

Author: chrispycheng

nibabel/cmdline/diff.py

@@ -62,10 +62,7 @@ def are_values_different(*values):
         if type(value0) != type(value):  # if types are different, then we consider them different
             return True
         elif isinstance(value0, np.ndarray):
-            if np.any(value0 != value):  # special test for ndarray
-                return True
-            else:
-                return False
+            return np.any(value0 != value)
 
         elif value0 != value:
             return True
@@ -104,7 +101,18 @@ def get_headers_diff(file_headers, names=None):
     return difference
 
 
-def get_data_md5sums(files):
+def get_data_diff(files):
+    """Get difference between md5 values
+
+        Parameters
+        ----------
+        files: list of actual files
+
+        Returns
+        -------
+        list
+          np.array: md5 values of respective files
+        """
 
     md5sums = [
         hashlib.md5(np.ascontiguousarray(nib.load(f).get_data(), dtype=np.float32)).hexdigest()
@@ -177,18 +185,15 @@ def main(args=None, out=None):
 
     file_headers = [nib.load(f).header for f in files]
 
-    if opts:  # will almost always have a header field
-        # signals "all fields"
-        if opts.header_fields == 'all':
-            # TODO: header fields might vary across file types, thus prior sensing would be needed
-            header_fields = file_headers[0].keys()
-        else:
-            header_fields = opts.header_fields.split(',')
-    else:
+    # signals "all fields"
+    if opts.header_fields == 'all':
+        # TODO: header fields might vary across file types, thus prior sensing would be needed
         header_fields = file_headers[0].keys()
+    else:
+        header_fields = opts.header_fields.split(',')
 
     diff = get_headers_diff(file_headers, header_fields)
-    data_diff = get_data_md5sums(files)
+    data_diff = get_data_diff(files)
 
     if data_diff:
         diff['DATA(md5)'] = data_diff
@@ -199,3 +204,4 @@ def main(args=None, out=None):
 
     else:
         out.write("These files are identical.\n")
+        raise SystemExit(0)

nibabel/cmdline/tests/test_utils.py

@@ -11,7 +11,7 @@
 import nibabel as nib
 import numpy as np
 from nibabel.cmdline.utils import *
-from nibabel.cmdline.diff import get_headers_diff, display_diff, main
+from nibabel.cmdline.diff import get_headers_diff, display_diff, main, get_data_diff
 from os.path import (join as pjoin)
 from nibabel.testing import data_path
 from collections import OrderedDict
@@ -110,6 +110,13 @@ def test_display_diff():
     assert_equal(display_diff(bogus_names, dict_values), expected_output)
 
 
+def test_get_data_diff():
+    #  testing for identical files specifically as md5 may vary by computer
+    test_names = [pjoin(data_path, f)
+                  for f in ('standard.nii.gz', 'standard.nii.gz')]
+    assert_equal(get_data_diff(test_names), [])
+
+
 def test_main():
     test_names = [pjoin(data_path, f)
                   for f in ('standard.nii.gz', 'example4d.nii.gz')]
@@ -150,3 +157,8 @@ def test_main():
 
     with assert_raises(SystemExit):
         np.testing.assert_equal(main(test_names, StringIO()), expected_difference)
+
+    test_names_2 = [pjoin(data_path, f) for f in ('standard.nii.gz', 'standard.nii.gz')]
+
+    with assert_raises(SystemExit):
+        assert_equal(main(test_names_2, StringIO()), "These files are identical.")

nibabel/tests/data/spmT_0001.nii.gz

@@ -75,7 +75,7 @@ def check_nib_diff_examples():
     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"]
+                      "srow_y", "srow_z", "DATA(md5)"]
     for item in checked_fields:
         assert_true(item in stdout)
 
@@ -84,6 +84,18 @@ def check_nib_diff_examples():
     code, stdout, stderr = run_command(['nib-diff'] + fnames2, check_code=False)
     assert_equal(stdout, "These files are identical.")
 
+    fnames3 = [pjoin(DATA_PATH, f)
+               for f in ('standard.nii.gz', 'example4d.nii.gz', 'example_nifti2.nii.gz')]
+    code, stdout, stderr = run_command(['nib-diff'] + fnames3, check_code=False)
+    for item in checked_fields:
+        assert_true(item in stdout)
+
+    fnames4 = [pjoin(DATA_PATH, f)
+               for f in ('standard.nii.gz', 'standard.nii.gz', 'standard.nii.gz')]
+    code, stdout, stderr = run_command(['nib-diff'] + fnames4, check_code=False)
+    assert_equal(stdout, "These files are identical.")
+
+
 
 @script_test
 def test_nib_ls():