added check to avoid removing referenced models #278

[fehguy]

Fixes #278

@diegode this is to fix the issue in #278 but...

I don't necessarily agree with the expectations in a couple tests. Once I fixed this bug some other test failures appeared.

For example, when we have this:

definitions:
  x:
    properties:
      foo:
        $ref: '#/definitions/y'
  y:
    $ref: '#/definitions/z'
  z:
    type: object

That the parser should change the definitions to this:

definitions:
  x:
    properties:
      foo:
        $ref: '#/definitions/z'
  z:
    type: object

Because a model is referencing y in this example as a property, there may be intent and value in retaining that name. So even though y absorbs all the properties of z, the name y may be useful.

So this PR changes the behavior of a couple tests that were previously behaving differently. Since you put them there, I thought it was only considerate to get your feedback before any merge :)

[fehguy]

Note that y lives on, even though it is directly referencing all aspects of z

[fehguy]

Instead of changing the reference to x, I'm leaving it as modeled as y

[fehguy]

OK I've reviewed the behavior with a few others and this PR and test changes seem correct. We don't want this:

definitions:
  Address:
    type: object
    # properties:...
  AlternateAddress:
    $ref: '#/definitions/Address'

to remove the Address definition and change references to AlternateAddress. @diegode please open a new issue if you disagree.