Audit unit test coverage

[arschles]

As of this writing, coverage is just over 50%. We should intelligently look for ways to increase it, then write the tests to do so.

[jackfrancis]

At the very least this issue will include bringing server_test.go.TestPostClusters up to speed with the standard idiom for this project. Don't use that as an excuse not to increase overall coverage!

[jackfrancis]

Update make test to include the -cover option so we can track coverage over time.

[arschles]

punting this to beta4

[arschles]

Moving this to RC1

[arschles]

Also note that test coverage has been significantly increased as the codebase has grown. We'll need to check the coverage again. I hope we can close this pretty early in the RC1 cycle.

[jackfrancis]

I've changed this ticket to "Audit unit test coverage", as the project has progressed enough that we'll want to target unit test coverage more explicitly. The objective of this ticket is to "componentize" missing unit test coverage areas, and to create specific issues to improve unit test coverage in particular areas of code so that the scope doesn't become overwhelming, and is easy to distribute among multiple contributors.