Issue with Measurement Group Name Check in _count_roi_items()

[whollervi]

Hi all,

First of all, thanks for highdicom — it really makes working with DICOM SRs (TID 1500) much easier!

However, I ran into a small issue when parsing a TID 1500 SR that was not created with highdicom.

I received the following error:

SR Content Item does not represent a measurement group because it does not have name "Measurement Group".

It seems this might be related to SRs missing the Template ID for a Measurement Group (e.g., TID 1501).
Looking into sr/templates.py, specifically _count_roi_items(), I noticed this logic:

if group_item.name == codes.DCM.MeasurementGroup:
    raise ValueError(
        'SR Content Item does not represent a measurement group '
        'because it does not have name "Measurement Group".'
    )

The check needs to be inverted to raise the error if the name does not match "Measurement Group"?

Thanks again for your great work, and let me know if I can help further with this!

Best,
Wolfgang

[CPBridge]

Hi @whollervi thanks for the feedback! One-character fixes are my favourite type of bug :)

Unfortunately though it seems that the case of missing template identifiers is never actually tested in the test suite, so I'll work on a more complete PR that also adds regression testing for this problem soon