Create validate, contain_in_change_set and have_change_set_failed matchers

[patrobinson]

This is an initial version of the library we can use to test our Sparkle Packs. It enables you to test a SparkleFormation or CloudFormation template to ensure:

• It compiles
• It is "valid"
• It generates a valid change set
• The generated change set contains the desired resources, with specific resource names

My goal is to make this library Open Source pretty shortly, feel free give any feedback here about that plan.

[jacobbednarz]

Looks like a great place to start! One thing I'm going to advise is that you make the gem name specific to what it's actually doing. "cloud spec" is quite ambiguous and doesn't really tell people what it's meant to be for. I would opt for something like cloudformation-rspec and follow the pattern of other libraries that implement RSpec matchers.

[patrobinson]

@andrewjhumphrey @jacobbednarz sorry I wasn't quite happy with this work, as I wanted to allow the be_valid matcher to accept SparkleFormation. There's now a be_valid_sparkleformation matcher, this required abstracting the ChangeSet code and SparkleFormation compilation to seperate classes and a re-write of most of the tests.