for this kind of test, I prefer to be able to read the input data litterally. Otherwise the reader need to pay way much more attention to get what self.date_visit is (what type) and pay extra attention to the presence of the str() call.
It's much easier to read as:
'date': '2019-01-15 10 15:35:27 CET'
Build has FAILED
Link to build: https://jenkins.softwareheritage.org/job/DSTO/job/tox/451/
See console output for more information: https://jenkins.softwareheritage.org/job/DSTO/job/tox/451/console