Deprecation warnings when running rake spec

```
*** Mocha deprecation warning: Change `require 'mocha'` to `require 'mocha/setup'`.


*** Mocha deprecation warning: Test::Unit or MiniTest must be loaded *before* Mocha.


*** Mocha deprecation warning: If you're integrating with a test library other than Test::Unit or MiniTest, you should use `require 'mocha/api'` instead of `require 'mocha'`.
```