Running unit tests causes failure

[diptorupd]

On running python -m unittest dpctl.tests the test suite passes but then I get this failure.

Exception ignored in: <function Runtime.__del__ at 0x7f0ba8c7cb00>
Traceback (most recent call last):
  File "/home/diptorupd/Desktop/devel/dpctl/dpctl/ocldrv.py", line 543, in __del__
AttributeError: 'NoneType' object has no attribute '_runtime'

The issue does not happen if I go into the dpctl directory and then do python -m unittest tests