Create test to check that Jenkins and Travis are catching errors

We've had issues in the past with both Jenkins and Travis showing as successful, when the logs show that the tests inside failed.
Can we create some test to check that these are each throwing errors when they should?

No files or test entry points are named. Start by locating the Jenkins and Travis configuration and the Python test commands they run; done means a deliberately failing test makes each service report failure instead of success.

Written by the indexing model from the issue text.