main test corrected for max coverage

Author: chrispycheng

nibabel/cmdline/diff.py

@@ -161,24 +161,17 @@ def display_diff(files, diff):
     return output
 
 
-def main(args=None):
+def main(args=None, out=None):
     """Getting the show on the road"""
-    try:
-        parser = get_opt_parser()
-        (opts, files) = parser.parse_args()
+    out = out or sys.stdout
+    parser = get_opt_parser()
+    (opts, files) = parser.parse_args(args)
 
-        nibabel.cmdline.utils.verbose_level = opts.verbose
+    nibabel.cmdline.utils.verbose_level = opts.verbose
 
-        if nibabel.cmdline.utils.verbose_level < 3:
-            # suppress nibabel format-compliance warnings
-            nib.imageglobals.logger.level = 50
-
-    except SystemExit:
-        opts = None
-        files = None
-
-    if args:
-        files = args
+    if nibabel.cmdline.utils.verbose_level < 3:
+        # suppress nibabel format-compliance warnings
+        nib.imageglobals.logger.level = 50
 
     assert len(files) >= 2, "Please enter at least two files"
 
@@ -201,11 +194,8 @@ def main(args=None):
         diff['DATA(md5)'] = data_diff
 
     if diff:
-        if opts:
-            sys.stdout.write(display_diff(files, diff))
-            raise SystemExit(1)
-        else:
-            return diff  # this functionality specifically for testing main
+        out.write(display_diff(files, diff))
+        raise SystemExit(1)
 
     else:
-        print("These files are identical.")
+        out.write("These files are identical.\n")

nibabel/cmdline/tests/test_utils.py

@@ -15,6 +15,7 @@
 from os.path import (join as pjoin)
 from nibabel.testing import data_path
 from collections import OrderedDict
+from io import StringIO
 
 
 def test_table2string():
@@ -111,7 +112,7 @@ def test_display_diff():
 
 def test_main():
     test_names = [pjoin(data_path, f)
-              for f in ('standard.nii.gz', 'example4d.nii.gz')]
+                  for f in ('standard.nii.gz', 'example4d.nii.gz')]
     expected_difference = OrderedDict([
         ("regular", [np.asarray("".encode("utf-8")), np.asarray("r".encode("utf-8"))]),
         ("dim_info", [np.asarray(0).astype(dtype="uint8"), np.asarray(57).astype(dtype="uint8")]),
@@ -147,4 +148,5 @@ def test_main():
                               -7.24879837e+00]).astype(dtype="float32")]),
         ('DATA(md5)', ['0a2576dd6badbb25bfb3b12076df986b', 'b0abbc492b4fd533b2c80d82570062cf'])])
 
-    np.testing.assert_equal(main(test_names), expected_difference)
+    with assert_raises(SystemExit):
+        np.testing.assert_equal(main(test_names, StringIO()), expected_difference)