While the test pass, it shouldn't report this exception. Testing infrastructure should also be improved to catch this error.

This change is independent of the Python3 updates and occurred with Slicer <= r28055 (see http://slicer.cdash.org/testDetails.php?test=9549115&amp;build=1551601)

$ ctest -R DICOMReader -V
[...]
Irregular volume geometry detected (maximum error of 16.5664 mm is above tolerance threshold of 0.001 mm).  Regularization transform is not added, as the option is disabled.
Traceback (most recent call last):
  File "/Volumes/Dashboards/Preview/Slicer-0/Applications/SlicerApp/Testing/Python/DICOMReaders.py", line 279, in test_MissingSlices
    if not numpy.allclose(scalarVolumePlugin.acquisitionModeling.fixedCorners[-1], lastSliceCorners):
AttributeError: 'AcquisitionModeling' object has no attribute 'fixedCorners'
Missing Slices Test caused exception!
'AcquisitionModeling' object has no attribute 'fixedCorners'
Restoring original database directory
[...]