vagrant-spec is a both a specification of how Vagrant and its various
components should behave as well as a library of testing helpers that let you
write your own unit and acceptance tests for Vagrant.
The library provides a set of helper methods in addition to RSpec matchers and
expectations to help you both unit test and acceptance test Vagrant
components. The RSpec components are built on top of the helper methods so
that the test library can be used with your test framework of choice, but the
entire tool is geared very heavily towards RSpec.