Add Tests

[gregoryvit]

No description provided.

[Atul9]

@gregoryvit I would like to contribute to test.
I checked the initialize method(XCBackyard::BackyardBuilder) and found that it calls sub! but that will return nil.
Example -

2.4.0 :007 > 'a/b/c'.sub! ('a' + 'b'), ''
 => nil 

[gregoryvit]

@Atul9 It is quite possible :)
I do not have much experience in ruby. And I will be appreciated to any advice or Pull Request from people with experience in it.