Fix writing typo, add writing tests

Author: kastman

nibabel/nifti1.py

@@ -411,14 +411,14 @@ def _is_little_endian(self):
         return True
 
     def _unmangle(self,value):
-        io=BytesIO(value)
-        ds=read_dataset(io,self._is_implicit_VR,self._is_little_endian)
+        raw_io=BytesIO(value)
+        ds=read_dataset(raw_io,self._is_implicit_VR,self._is_little_endian)
         return ds
 
-    def _mangle(self,value):
-        io=BytesIO()
-        dio=DicomFileLike(io)
-        dio.is_implicit_VR = self._is_implict_VR
+    def _mangle(self):
+        raw_io=BytesIO()
+        dio=DicomFileLike(raw_io)
+        dio.is_implicit_VR = self._is_implicit_VR
         dio.is_little_endian = self._is_little_endian
         ds_len=write_dataset(dio,self._content)
         dio.seek(0)
@@ -427,7 +427,7 @@ def _mangle(self,value):
     def get_sizeondisk(self):
         """Return the size of the extension in the NIfTI file.
         """
-        return len(self._mangle(self._content))
+        return len(self._mangle())
 
 try:
     from dicom.filereader import read_dataset

nibabel/tests/test_nifti1.py

@@ -1095,16 +1095,20 @@ def test_nifti_dicom_extension():
     assert_equal(len(dcmext.get_content().values()), 1)
 
     # create a single dicom tag (Patien ID, [0010,0020]) with Implicit VR
-    dcmext = Nifti1DicomExtension(2,
-        struct.pack('<HHL4s',0x10,0x20,4,'NiPy'.encode('utf-8')))
+    dcmbytes = struct.pack('<HHL4s',0x10,0x20,4,'NiPy'.encode('utf-8'))
+    dcmext = Nifti1DicomExtension(2,dcmbytes)
     assert_equal(dcmext.get_content().PatientID, 'NiPy')
     assert_equal(len(dcmext.get_content().values()), 1)
+    assert_equal(dcmext.get_sizeondisk(), len(dcmbytes))
+    assert_equal(dcmext._mangle(),dcmbytes)
 
     # dicom extension access from nifti extensions
     assert_equal(exts_container.count('dicom'),0)
     exts_container.append(dcmext)
     assert_equal(exts_container.count('dicom'), 1)
     assert_equal(exts_container.get_codes(), [6, 6, 2])
+    assert_equal(dcmext.get_sizeondisk(), len(dcmbytes))
+    assert_equal(dcmext._mangle(),dcmbytes)
     # assert_equal((exts_container.get_sizeondisk()) % 16, 0)
 
 class TestNifti1General(object):