Decide and migrate to new test framework

[makinde]

This doesn't have to be high-pri, but we should think about this at some point. nodeunit is now deprecated.

tape seems like the closest alternative that would be a pretty easy switch, though it doesn't have the setUp and tearDown methods we use currently. We could simply have a setUp function that every test calls.

The other similar framework is ava. That has the setUp/tearDown stuff (along with lots of other great stuff), but doesn't have grouping. We'd also need to tell it to run our tests serially since all our tests share the same db connection.

[brysgo]

Jest has an option to run in band :-)

https://facebook.github.io/jest/docs/en/cli.html#runinband

Has bdd "grouping" and "beforeAll", "beforeEach", "afterAll", and "afterEach"