change tostr -> tobytes for deprecation, add basic test

heudiconv/heuristics/convertall.py

@@ -26,7 +26,7 @@ def custom_seqinfo(wrapper: dw.Wrapper, series_files: list[str], **kw: Any) -> t
     # in https://github.com/nipy/heudiconv/pull/333
     from nibabel.nicom.dicomwrappers import WrapperError
     try:
-        affine = wrapper.affine.tostring()
+        affine = wrapper.affine.tobytes()
     except WrapperError:
         lgr.exception("Errored out while obtaining/converting affine")
         affine = None

heudiconv/tests/test_dicoms.py

@@ -99,6 +99,26 @@ def test_group_dicoms_into_seqinfos() -> None:
     ]
 
 
+def test_custom_seqinfo() -> None:
+    """Tests for custom seqinfo extraction"""
+
+    from heudiconv.heuristics.convertall import custom_seqinfo
+
+    dcmfiles = glob(op.join(TESTS_DATA_PATH, "phantom.dcm"))
+
+    seqinfos = group_dicoms_into_seqinfos(
+        dcmfiles,
+        "studyUID",
+        flatten=True,
+        custom_seqinfo=custom_seqinfo)
+
+    seqinfo = list(seqinfos.keys())[0]
+
+    assert hasattr(seqinfo, 'custom')
+    assert isinstance(seqinfo.custom, tuple)
+    assert len(seqinfo.custom) == 2
+    assert seqinfo.custom[1] == dcmfiles[0]
+
 def test_get_datetime_from_dcm_from_acq_date_time() -> None:
     typical_dcm = dcm.dcmread(
         op.join(TESTS_DATA_PATH, "phantom.dcm"), stop_before_pixels=True