Increase test coverage

[jpmckinney]

Priority is process_manager, because a bad change in behavior can do things like schedule tons of jobs. For is_out_of_date, if it returns true, schedule a job, then call it again to ensure it returns false.

Test that all task managers can call wipe without error.

Second priority is views (can add tests next time we work on views).

[jpmckinney]

Can experiment with https://github.com/plasma-umass/coverup