Moved to rails-based testing

[exoego]

This PR erases unit tests added in #55 and uses rails-rspec-based testing instead.
A small subset of existing OpenAPI file and test cases are added as test fixtures.

The below diff demonstrates how smart merge updates the existing fields.

❯ diff -u spec/rails/doc/smart/openapi.yaml spec/rails/doc/smart/expected.yaml
--- spec/rails/doc/smart/openapi.yaml   2022-05-27 06:51:14.000000000 +0900
+++ spec/rails/doc/smart/expected.yaml  2022-05-27 06:51:14.000000000 +0900
@@ -87,7 +87,7 @@
                     type: string
                     example: This field does not exist in rspec
               example:
-                message: This field should be updated by rspec
+                message: Unauthorized
     post:
       summary: create
       tags:
@@ -128,7 +128,7 @@
                 updated_at: '2020-07-17T00:00:00+00:00'
   "/tables/{id}":
     get:
-      summary: This filed should be updated by rspec
+      summary: show
       tags:
       - Table
       parameters:

The below diff indicates the current limitation of smart merge: it can not remove the non-existent field no_such_field.
I will add field removal in #57 later, based on this PR.

❯ diff -u spec/rails/doc/smart/openapi.yaml spec/rails/doc/openapi.yaml
--- spec/rails/doc/smart/openapi.yaml   2022-05-27 06:51:14.000000000 +0900
+++ spec/rails/doc/openapi.yaml 2022-05-27 06:51:14.000000000 +0900
(snip)
@@ -83,11 +106,8 @@
                 properties:
                   message:
                     type: string
-                  no_such_field:
-                    type: string
-                    example: This field does not exist in rspec
               example:

Context

#57 (comment)

Can you test it by only adding YAML-level tests at spec/rspec/rails_spec.rb? The only thing that must be maintained in this repository is what OpenAPI schema is generated at each rspec execution, not internal methods to implement it. If you unit-test internal implementations, it becomes harder to refactor the implementation.

So I'm not comfortable having this kind of test when you could just write a test that fails only when needed. This test could fail when it doesn't need to, for example when we rename paths_to_all_fields to something else, which users don't care about. In fact, I actually don't appreciate tests under spec/rspec/schema_merger/ because the interface of RSpec::OpenAPI::SchemaMerger.merge! isn't part of the contact of this gem. Testing the same thing by reading a YAML file generated by running rspec would be more cost-effective because it would fail only when the actual contract is changed.

[k0kubun]

Can you just convert it to a normal YAML instead of a JSON?

[exoego]

Done in 3f9398f

[k0kubun]

Thanks 👍