enh: LTA + components tests

Author: mgxd

nitransforms/tests/test_io.py

@@ -2,10 +2,35 @@
 
 import numpy as np
 
-from ..io import LinearTransformArray as LTA
+from ..io import (
+    VolumeGeometry as VG,
+    LinearTransform as LT,
+    LinearTransformArray as LTA,
+)
 
 
-def test_LinearTransformArray_input(tmpdir, data_path):
+def test_VolumeGeometry(tmpdir, get_data):
+    vg = VG()
+    assert vg['valid'] == 0
+
+    img = get_data['RAS']
+    vg = VG.from_image(img)
+    assert vg['valid'] == 1
+    assert np.all(vg['voxelsize'] == img.header.get_zooms()[:3])
+    assert np.all(vg.as_affine() == img.affine)
+
+    assert len(vg.to_string().split('\n')) == 8
+
+
+def test_LinearTransform(tmpdir, get_data):
+    lt = LT()
+    assert lt['m_L'].shape == (4, 4)
+    assert np.all(lt['m_L'] == 0)
+    for vol in ('src', 'dst'):
+        assert lt[vol]['valid'] == 0
+
+
+def test_LinearTransformArray(tmpdir, data_path):
     lta = LTA()
     assert lta['nxforms'] == 0
     assert len(lta['xforms']) == 0
@@ -21,3 +46,11 @@ def test_LinearTransformArray_input(tmpdir, data_path):
     assert np.allclose(
         xform['m_L'], np.genfromtxt(test_lta, skip_header=5, skip_footer=20)
     )
+
+    outlta = (tmpdir / 'out.lta').strpath
+    with open(outlta, 'w') as fp:
+        fp.write(lta.to_string())
+
+    with open(outlta) as fp:
+        lta2 = LTA.from_fileobj(fp)
+    np.allclose(lta['xforms'][0]['m_L'], lta2['xforms'][0]['m_L'])