I think you have found a bug in qutip. The HTML progress bar seems to be broken in current versions of jupyter notebook. I have submitted a bug report here:
https://github.com/qutip/qutip/issues/2475
Three quick other comments:
* The recommended way of running the qutip test suite is on the command line, using `pytest .../qutip/tests`. At least for me, the tests run faster outside jupyter by several orders of magnitude.
* If you run the tests over the command line, you should find that there is no error, since the HTML progress bar tests are automatically skipped on the command line. (Which is why people haven't noticed this problem before.)
Best regards,
Paul