Support YAML output

.travis.yml

@@ -1,10 +1,19 @@
 language: ruby
 rvm:
-  - 2.2.5
+  - 2.2
+  - 2.3
+  - 2.4
+  - 2.5
 env:
-  - "RAILS_VERSION=3.2.0"
-  - "RAILS_VERSION=4.2.0"
-  - "RAILS_VERSION=5.0.0"
+  - RAILS_VERSION=3.2.0
+  - RAILS_VERSION=4.2.0
+  - RAILS_VERSION=5.1.0
 cache: bundler
 install: ./make_site.sh
 script: bundle exec rspec
+matrix:
+  exclude:
+  - rvm: 2.4
+    env: RAILS_VERSION=3.2.0
+  - rvm: 2.5
+    env: RAILS_VERSION=3.2.0

lib/rspec/rails/swagger/formatter.rb

@@ -44,7 +44,7 @@ def example_finished(notification)
         end
 
         def close(_notification)
-          documents.each{|k, v| write_json(k, v)}
+          documents.each{|k, v| write_file(k, v)}
 
           self
         end
@@ -70,13 +70,33 @@ def example_output(notification)
           " #{notification.example.metadata[:swagger_response][:status_code]}"
         end
 
-        def write_json(name, document)
-          root = ::RSpec.configuration.swagger_root
+        def write_file(name, document)
+          output =
+            if %w(.yaml .yml).include? File.extname(name)
+              YAML.dump(deep_stringify_keys(document))
+            else
+              JSON.pretty_generate(document) + "\n"
+            end
+
           # It would be good to at least warn if the name includes some '../' that
           # takes it out of root directory.
-          target = Pathname(name).expand_path(root)
+          target = Pathname(name).expand_path(::RSpec.configuration.swagger_root)
           target.dirname.mkpath
-          target.write(JSON.pretty_generate(document))
+          target.write(output)
+        end
+
+        # Lifted from ActiveSupport's Hash _deep_transform_keys_in_object
+        def deep_stringify_keys(object)
+          case object
+          when Hash
+            object.each_with_object({}) do |(key, value), result|
+              result[key.to_s] = deep_stringify_keys(value)
+            end
+          when Array
+            object.map { |e| deep_stringify_keys(e) }
+          else
+            object
+          end
         end
 
         def document_for(doc_name = nil)

spec/rspec/rails/swagger/formatter_spec.rb

@@ -94,8 +94,8 @@ def minimal
       context "with a default formatter" do
         before(:example) do
           RSpec::Rails::Swagger::ResponseFormatters.register(
-              'application/json',
-              RSpec::Rails::Swagger::ResponseFormatters::JSON.new
+            'application/json',
+            RSpec::Rails::Swagger::ResponseFormatters::JSON.new
           )
         end
 
@@ -119,7 +119,7 @@ def minimal
 
     context "no relevant examples" do
       it "writes document with no changes" do
-        expect(formatter).to receive(:write_json).with(documents.keys.first, documents.values.first)
+        expect(formatter).to receive(:write_file).with(documents.keys.first, documents.values.first)
         formatter.close(blank_notification)
       end
     end
@@ -130,21 +130,22 @@ def minimal
         {
           swagger_object: :response,
           swagger_path_item: {path: "/ping"},
-          swagger_operation: {method: :get},
+          swagger_operation: {method: :get, produces: ["application/json"]},
           swagger_response:  {status_code: 200, description: 'all good'},
         }
       end
 
       it "writes a document with the request" do
         formatter.example_finished(example_notification)
 
-        expect(formatter).to receive(:write_json).with(
+        expect(formatter).to receive(:write_file).with(
           documents.keys.first,
           documents.values.first.merge({
             paths: {
               '/ping' => {
                 get: {
-                  responses: {200 => {description: 'all good'}}
+                  responses: {200 => {description: 'all good'}},
+                  produces: ["application/json"]
                 }
               }
             }
@@ -153,6 +154,72 @@ def minimal
 
         formatter.close(blank_notification)
       end
+
+      describe 'output formats' do
+        let(:documents) { {file_name => minimal} }
+
+        subject do
+          formatter.example_finished(example_notification)
+          formatter.close(blank_notification)
+          Pathname(file_name).expand_path(::RSpec.configuration.swagger_root).read
+        end
+
+        %w(yaml yml).each do |extension|
+          context "with a name that ends in .#{extension}" do
+            let(:file_name) { "minimal.#{extension}" }
+
+            it 'outputs YAML' do
+              expect(subject).to eq <<YAML
+---
+swagger: '2.0'
+info:
+  version: 0.0.0
+  title: Simple API
+paths:
+  "/ping":
+    get:
+      responses:
+        '200':
+          description: all good
+      produces:
+      - application/json
+YAML
+            end
+          end
+        end
+
+        %w(json txt).each do |extension|
+          context "with a name that ends in .#{extension}" do
+            let(:file_name) { "minimal.#{extension}" }
+
+            it 'outputs JSON' do
+              expect(subject).to eq <<JSON
+{
+  "swagger": "2.0",
+  "info": {
+    "version": "0.0.0",
+    "title": "Simple API"
+  },
+  "paths": {
+    "/ping": {
+      "get": {
+        "responses": {
+          "200": {
+            "description": "all good"
+          }
+        },
+        "produces": [
+          "application/json"
+        ]
+      }
+    }
+  }
+}
+JSON
+            end
+          end
+        end
+      end
     end
   end
 end

spec/swagger_helper.rb

@@ -7,11 +7,18 @@
 
   # Define one or more Swagger documents and global metadata for each.
   #
-  # When you run the "swaggerize" rake task, the complete Swagger will be
+  # When you run the "swagger" rake task, the complete Swagger will be
   # generated at the provided relative path under `swagger_root`
+  #
+  # If the file name ends with .yml or .yaml the contents will be YAML,
+  # otherwise the file will be JSON.
+  #
   # By default, the operations defined in spec files are added to the first
-  # document below. You can override this behavior by adding a swagger_doc tag to the
-  # the root example_group in your specs, e.g. describe '...', swagger_doc: 'v2/swagger.json'
+  # document below. You can override this behavior by adding a `swagger_doc` tag
+  # to the the root example_group in your specs, e.g.
+  #
+  #   describe '...', swagger_doc: 'v2/swagger.json'
+  #
   config.swagger_docs = {
     'v1/swagger.json' => {
       swagger: '2.0',