On my laptop, which typically has two working interfaces (wired & wireless), each with a default route, the testsuite fails in pasta_options/log_to_file. Specifically it's failing on the test for truncation of the logfile on start up. It's looking for a logfile of exactly one line, but the log is longer than that due to the information messages about multiple default routes.
Fixed by commit ff2ff2fbca75352ff027a90d6341645f1dea4e50 ("test: Make log truncation test more robust").