Fix problem with undefined status code method for Rack::MockResponse

[grzesiek]

Hi.

This patch fixes problem for expect_status Airborne DSL method.

When used with Rack application, expect_status compares status code passed to that method with value returned by response.code method. That method does not exist in Rack::MockRequest.

https://github.com/brooklynDev/airborne/blob/master/lib/airborne/request_expectations.rb#L34

There is status method in Rack::MockRequest instead.

This commit adds method code that is alias for status in Rack::MockResponse

Kind regards,
Grzegorz

[coveralls]

Coverage increased (+0.0%) when pulling 05bf398 on grzesiek:rack-response-fix into e3d75dc on brooklynDev:master.

[grzesiek]

Or maybe define_singleton_method would be better here ?

[brooklynDev]

Good catch! We don't actually have enough tests for Rack applications, and that's probably how this one got through. I merged your PR, and I'll try to flesh out the test suite for Rack apps. (Unless if you want to 😄 )