Add support for 'brackets' collection format (#622)

* Add support for 'brackets' collection format

* Update changelog.md

Author: korstiaan

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 #### Features
 
-* Your contribution here.
+* [#622](https://github.com/ruby-grape/grape-swagger/pull/622): Add support for 'brackets' collection format - [@korstiaan](https://github.com/korstiaan).
 
 #### Fixes
 

lib/grape-swagger/doc_methods/data_type.rb

@@ -80,7 +80,7 @@ def mapping(value)
         end
 
         def collections
-          %w[csv ssv tsv pipes multi]
+          %w[csv ssv tsv pipes multi brackets]
         end
       end
 

spec/swagger_v2/params_array_collection_fromat_spec.rb

@@ -31,6 +31,14 @@ def app
         { 'declared_params' => declared(params) }
       end
 
+      params do
+        optional :array_of_strings, type: Array[String], desc: 'array in brackets collection format', documentation: { collectionFormat: 'brackets' }
+      end
+
+      get '/array_of_strings_brackets_collection_format' do
+        { 'declared_params' => declared(params) }
+      end
+
       add_swagger_documentation
     end
   end
@@ -65,6 +73,21 @@ def app
     end
   end
 
+  describe 'documentation for array parameters in brackets collectionFormat set from documentation' do
+    subject do
+      get '/swagger_doc/array_of_strings_brackets_collection_format'
+      JSON.parse(last_response.body)
+    end
+
+    specify do
+      expect(subject['paths']['/array_of_strings_brackets_collection_format']['get']['parameters']).to eql(
+        [
+          { 'in' => 'formData', 'name' => 'array_of_strings', 'type' => 'array', 'items' => { 'type' => 'string' }, 'required' => false, 'collectionFormat' => 'brackets', 'description' => 'array in brackets collection format' }
+        ]
+      )
+    end
+  end
+
   describe 'documentation for array parameters with collectionFormat set to invalid option' do
     subject do
       get '/swagger_doc/array_of_strings_invalid_collection_format'