enh: added a couple of minor tests for ITK-arrays' to_filename

Author: oesteban

nitransforms/io/itk.py

@@ -83,7 +83,7 @@ def to_string(self, banner=None):
         return string % self
 
     @classmethod
-    def from_binary(cls, byte_stream, index=None):
+    def from_binary(cls, byte_stream, index=0):
         """Read the struct from a matlab binary file."""
         mdict = _read_mat(byte_stream)
         return cls.from_matlab_dict(mdict, index=index)
@@ -96,14 +96,12 @@ def from_fileobj(cls, fileobj, check=True):
         return cls.from_string(fileobj.read())
 
     @classmethod
-    def from_matlab_dict(cls, mdict, index=None):
+    def from_matlab_dict(cls, mdict, index=0):
         """Read the struct from a matlab dictionary."""
         tf = cls()
         sa = tf.structarr
-        if index is not None:
-            raise NotImplementedError
 
-        sa['index'] = 0
+        sa['index'] = index
         parameters = np.eye(4, dtype='f4')
         parameters[:3, :3] = mdict['AffineTransform_float_3_3'][:-3].reshape((3, 3))
         parameters[:3, 3] = mdict['AffineTransform_float_3_3'][-3:].flatten()
@@ -184,7 +182,7 @@ def __getitem__(self, idx):
     def to_filename(self, filename):
         """Store this transform to a file with the appropriate format."""
         if str(filename).endswith('.mat'):
-            raise NotImplementedError
+            raise TransformFileError('Please use the ITK\'s new .h5 format.')
 
         with open(str(filename), 'w') as f:
             f.write(self.to_string())

nitransforms/tests/test_io.py

@@ -108,6 +108,11 @@ def test_ITKLinearTransformArray(tmpdir, data_path):
         itk.ITKLinearTransformArray.from_string(
             '\n'.join(text.splitlines()[1:]))
 
+    itklist.to_filename('copy.tfm')
+    with open('copy.tfm') as f:
+        copytext = f.read()
+    assert text == copytext
+
     itklist = itk.ITKLinearTransformArray(
         xforms=[np.random.normal(size=(4, 4))
                 for _ in range(4)])
@@ -128,6 +133,11 @@ def test_ITKLinearTransformArray(tmpdir, data_path):
     assert np.allclose(xfm.structarr['parameters'][:3, ...],
                        xfm2.structarr['parameters'][:3, ...])
 
+    with pytest.raises(TransformFileError):
+        itklist.to_filename('matlablist.mat')
+
+
+
 
 @pytest.mark.parametrize('matlab_ver', ['4', '5'])
 def test_read_mat1(tmpdir, matlab_ver):