diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index 04940c0fe..d0d40c872 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -1,54 +1,117 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config`
-# on 2017-07-11 00:59:31 +0100 using RuboCop version 0.47.0.
+# on 2017-12-10 01:00:44 +0900 using RuboCop version 0.51.0.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
 # versions of RuboCop, may require this file to be generated again.
 
-# Offense count: 45
+# Offense count: 7
+# Cop supports --auto-correct.
+# Configuration parameters: EnforcedStyle, SupportedStyles.
+# SupportedStyles: auto_detection, squiggly, active_support, powerpack, unindent
+Layout/IndentHeredoc:
+  Exclude:
+    - 'lib/grape/router/route.rb'
+    - 'spec/grape/api_spec.rb'
+    - 'spec/grape/entity_spec.rb'
+
+# Offense count: 2
+Lint/AmbiguousBlockAssociation:
+  Exclude:
+    - 'lib/grape/middleware/stack.rb'
+    - 'spec/grape/dsl/routing_spec.rb'
+
+# Offense count: 1
+Lint/RescueWithoutErrorClass:
+  Exclude:
+    - 'lib/grape/validations/validators/coerce.rb'
+
+# Offense count: 49
 Metrics/AbcSize:
   Max: 44
 
-# Offense count: 279
+# Offense count: 285
 # Configuration parameters: CountComments, ExcludedMethods.
 Metrics/BlockLength:
   Max: 3117
 
-# Offense count: 8
+# Offense count: 9
 # Configuration parameters: CountComments.
 Metrics/ClassLength:
   Max: 288
 
-# Offense count: 28
+# Offense count: 32
 Metrics/CyclomaticComplexity:
   Max: 14
 
-# Offense count: 1114
+# Offense count: 1160
 # Configuration parameters: AllowHeredoc, AllowURI, URISchemes, IgnoreCopDirectives, IgnoredPatterns.
 # URISchemes: http, https
 Metrics/LineLength:
   Max: 215
 
-# Offense count: 56
+# Offense count: 57
 # Configuration parameters: CountComments.
 Metrics/MethodLength:
   Max: 33
 
-# Offense count: 10
+# Offense count: 11
 # Configuration parameters: CountComments.
 Metrics/ModuleLength:
   Max: 212
 
-# Offense count: 17
+# Offense count: 21
 Metrics/PerceivedComplexity:
   Max: 14
 
-# Offense count: 2
+# Offense count: 4
+# Configuration parameters: ExpectMatchingDefinition, Regex, IgnoreExecutableScripts, AllowedAcronyms.
+# AllowedAcronyms: CLI, DSL, ACL, API, ASCII, CPU, CSS, DNS, EOF, GUID, HTML, HTTP, HTTPS, ID, IP, JSON, LHS, QPS, RAM, RHS, RPC, SLA, SMTP, SQL, SSH, TCP, TLS, TTL, UDP, UI, UID, UUID, URI, URL, UTF8, VM, XML, XMPP, XSRF, XSS
+Naming/FileName:
+  Exclude:
+    - 'Appraisals'
+    - 'Gemfile'
+    - 'Guardfile'
+    - 'Rakefile'
+
+# Offense count: 1
+# Configuration parameters: Blacklist.
+# Blacklist: END, (?-mix:EO[A-Z]{1})
+Naming/HeredocDelimiterNaming:
+  Exclude:
+    - 'lib/grape/router/route.rb'
+
+# Offense count: 3
+# Cop supports --auto-correct.
+# Configuration parameters: AutoCorrect.
+Performance/HashEachMethods:
+  Exclude:
+    - 'lib/grape/api.rb'
+    - 'lib/grape/middleware/versioner/header.rb'
+
+# Offense count: 1
+# Cop supports --auto-correct.
+# Configuration parameters: EnforcedStyle, SupportedStyles, ProceduralMethods, FunctionalMethods, IgnoredMethods.
+# SupportedStyles: line_count_based, semantic, braces_for_chaining
+# ProceduralMethods: benchmark, bm, bmbm, create, each_with_object, measure, new, realtime, tap, with_object
+# FunctionalMethods: let, let!, subject, watch
+# IgnoredMethods: lambda, proc, it
 Style/BlockDelimiters:
   Exclude:
     - 'spec/grape/middleware/formatter_spec.rb'
 
+# Offense count: 1
+Style/CommentedKeyword:
+  Exclude:
+    - 'spec/grape/validations_spec.rb'
+
+# Offense count: 2
+# Configuration parameters: SupportedStyles.
+# SupportedStyles: annotated, template
+Style/FormatStringToken:
+  EnforcedStyle: template
+
 # Offense count: 2
 Style/IdenticalConditionalBranches:
   Exclude:
@@ -58,3 +121,8 @@ Style/IdenticalConditionalBranches:
 Style/MethodMissing:
   Exclude:
     - 'lib/grape/router/attribute_translator.rb'
+
+# Offense count: 1
+Style/MultipleComparison:
+  Exclude:
+    - 'lib/grape/validations/types/custom_type_coercer.rb'
diff --git a/Appraisals b/Appraisals
index 5ceb072bc..5bb876782 100644
--- a/Appraisals
+++ b/Appraisals
@@ -1,6 +1,6 @@
 appraise 'rails-3' do
   gem 'rails', '3.2.19'
-  gem 'rack-cache', '<= 1.2'  # Pin as next rack-cache version (1.3) removes Ruby1.9 support
+  gem 'rack-cache', '<= 1.2' # Pin as next rack-cache version (1.3) removes Ruby1.9 support
 end
 
 appraise 'rails-4' do
diff --git a/Gemfile b/Gemfile
index 2c95e4d45..b1a41e2c9 100644
--- a/Gemfile
+++ b/Gemfile
@@ -6,28 +6,28 @@ gemspec
 
 group :development, :test do
   gem 'bundler'
-  gem 'rake'
-  gem 'rubocop', '0.47.0'
   gem 'hashie'
+  gem 'rake'
+  gem 'rubocop', '0.51.0'
 end
 
 group :development do
+  gem 'appraisal'
+  gem 'benchmark-ips'
   gem 'guard'
   gem 'guard-rspec'
   gem 'guard-rubocop'
-  gem 'appraisal'
-  gem 'benchmark-ips'
 end
 
 group :test do
+  gem 'cookiejar'
+  gem 'coveralls', '~> 0.8.17', require: false
+  gem 'danger-toc', '~> 0.1.0'
   gem 'grape-entity', '~> 0.6'
   gem 'maruku'
+  gem 'mime-types'
+  gem 'rack-jsonp', require: 'rack/jsonp'
   gem 'rack-test', '~> 0.6.3'
   gem 'rspec', '~> 3.0'
-  gem 'cookiejar'
-  gem 'rack-jsonp', require: 'rack/jsonp'
-  gem 'mime-types'
   gem 'ruby-grape-danger', '~> 0.1.0', require: false
-  gem 'coveralls', '~> 0.8.17', require: false
-  gem 'danger-toc', '~> 0.1.0'
 end
diff --git a/Rakefile b/Rakefile
index a62ec8562..2beb99875 100644
--- a/Rakefile
+++ b/Rakefile
@@ -22,5 +22,4 @@ require 'rainbow/ext/string' unless String.respond_to?(:color)
 require 'rubocop/rake_task'
 RuboCop::RakeTask.new
 
-task default: [:rubocop, :spec]
-
+task default: %i[rubocop spec]
diff --git a/gemfiles/multi_json.gemfile b/gemfiles/multi_json.gemfile
index 231ee1697..495befbf2 100644
--- a/gemfiles/multi_json.gemfile
+++ b/gemfiles/multi_json.gemfile
@@ -1,34 +1,35 @@
 # This file was generated by Appraisal
 
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'multi_json', require: 'multi_json'
+gem "multi_json", :require => "multi_json"
 
 group :development, :test do
-  gem 'bundler'
-  gem 'rake'
-  gem 'rubocop', '0.47.0'
-  gem 'hashie'
+  gem "bundler"
+  gem "hashie"
+  gem "rake"
+  gem "rubocop", "0.51.0"
 end
 
 group :development do
-  gem 'guard'
-  gem 'guard-rspec'
-  gem 'guard-rubocop'
-  gem 'appraisal'
-  gem 'benchmark-ips'
+  gem "appraisal"
+  gem "benchmark-ips"
+  gem "guard"
+  gem "guard-rspec"
+  gem "guard-rubocop"
 end
 
 group :test do
-  gem 'grape-entity', '~> 0.6'
-  gem 'maruku'
-  gem 'rack-test', '~> 0.6.3'
-  gem 'rspec', '~> 3.0'
-  gem 'cookiejar'
-  gem 'rack-jsonp', require: 'rack/jsonp'
-  gem 'mime-types'
-  gem 'ruby-grape-danger', '~> 0.1.0', require: false
-  gem 'coveralls', '~> 0.8.17', require: false
+  gem "cookiejar"
+  gem "coveralls", "~> 0.8.17", :require => false
+  gem "danger-toc", "~> 0.1.0"
+  gem "grape-entity", "~> 0.6"
+  gem "maruku"
+  gem "mime-types"
+  gem "rack-jsonp", :require => "rack/jsonp"
+  gem "rack-test", "~> 0.6.3"
+  gem "rspec", "~> 3.0"
+  gem "ruby-grape-danger", "~> 0.1.0", :require => false
 end
 
-gemspec path: '../'
+gemspec :path => "../"
diff --git a/gemfiles/multi_xml.gemfile b/gemfiles/multi_xml.gemfile
index b551d9dc0..13cb4a570 100644
--- a/gemfiles/multi_xml.gemfile
+++ b/gemfiles/multi_xml.gemfile
@@ -1,34 +1,35 @@
 # This file was generated by Appraisal
 
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'multi_xml', require: 'multi_xml'
+gem "multi_xml", :require => "multi_xml"
 
 group :development, :test do
-  gem 'bundler'
-  gem 'rake'
-  gem 'rubocop', '0.47.0'
-  gem 'hashie'
+  gem "bundler"
+  gem "hashie"
+  gem "rake"
+  gem "rubocop", "0.51.0"
 end
 
 group :development do
-  gem 'guard'
-  gem 'guard-rspec'
-  gem 'guard-rubocop'
-  gem 'appraisal'
-  gem 'benchmark-ips'
+  gem "appraisal"
+  gem "benchmark-ips"
+  gem "guard"
+  gem "guard-rspec"
+  gem "guard-rubocop"
 end
 
 group :test do
-  gem 'grape-entity', '~> 0.6'
-  gem 'maruku'
-  gem 'rack-test', '~> 0.6.3'
-  gem 'rspec', '~> 3.0'
-  gem 'cookiejar'
-  gem 'rack-jsonp', require: 'rack/jsonp'
-  gem 'mime-types'
-  gem 'ruby-grape-danger', '~> 0.1.0', require: false
-  gem 'coveralls', '~> 0.8.17', require: false
+  gem "cookiejar"
+  gem "coveralls", "~> 0.8.17", :require => false
+  gem "danger-toc", "~> 0.1.0"
+  gem "grape-entity", "~> 0.6"
+  gem "maruku"
+  gem "mime-types"
+  gem "rack-jsonp", :require => "rack/jsonp"
+  gem "rack-test", "~> 0.6.3"
+  gem "rspec", "~> 3.0"
+  gem "ruby-grape-danger", "~> 0.1.0", :require => false
 end
 
-gemspec path: '../'
+gemspec :path => "../"
diff --git a/gemfiles/rack_1.5.2.gemfile b/gemfiles/rack_1.5.2.gemfile
index 7207360b5..753f7d5b4 100644
--- a/gemfiles/rack_1.5.2.gemfile
+++ b/gemfiles/rack_1.5.2.gemfile
@@ -1,34 +1,35 @@
 # This file was generated by Appraisal
 
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rack', '1.5.2'
+gem "rack", "1.5.2"
 
 group :development, :test do
-  gem 'bundler'
-  gem 'rake'
-  gem 'rubocop', '0.47.0'
-  gem 'hashie'
+  gem "bundler"
+  gem "hashie"
+  gem "rake"
+  gem "rubocop", "0.51.0"
 end
 
 group :development do
-  gem 'guard'
-  gem 'guard-rspec'
-  gem 'guard-rubocop'
-  gem 'appraisal'
-  gem 'benchmark-ips'
+  gem "appraisal"
+  gem "benchmark-ips"
+  gem "guard"
+  gem "guard-rspec"
+  gem "guard-rubocop"
 end
 
 group :test do
-  gem 'grape-entity', '~> 0.6'
-  gem 'maruku'
-  gem 'rack-test', '~> 0.6.3'
-  gem 'rspec', '~> 3.0'
-  gem 'cookiejar'
-  gem 'rack-jsonp', require: 'rack/jsonp'
-  gem 'mime-types'
-  gem 'ruby-grape-danger', '~> 0.1.0', require: false
-  gem 'coveralls', '~> 0.8.17', require: false
+  gem "cookiejar"
+  gem "coveralls", "~> 0.8.17", :require => false
+  gem "danger-toc", "~> 0.1.0"
+  gem "grape-entity", "~> 0.6"
+  gem "maruku"
+  gem "mime-types"
+  gem "rack-jsonp", :require => "rack/jsonp"
+  gem "rack-test", "~> 0.6.3"
+  gem "rspec", "~> 3.0"
+  gem "ruby-grape-danger", "~> 0.1.0", :require => false
 end
 
-gemspec path: '../'
+gemspec :path => "../"
diff --git a/gemfiles/rack_edge.gemfile b/gemfiles/rack_edge.gemfile
index 11c2d0652..fedd2f681 100644
--- a/gemfiles/rack_edge.gemfile
+++ b/gemfiles/rack_edge.gemfile
@@ -1,34 +1,35 @@
 # This file was generated by Appraisal
 
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rack', github: 'rack/rack'
+gem "rack", :github => "rack/rack"
 
 group :development, :test do
-  gem 'bundler'
-  gem 'rake'
-  gem 'rubocop', '0.47.0'
-  gem 'hashie'
+  gem "bundler"
+  gem "hashie"
+  gem "rake"
+  gem "rubocop", "0.51.0"
 end
 
 group :development do
-  gem 'guard'
-  gem 'guard-rspec'
-  gem 'guard-rubocop'
-  gem 'appraisal'
-  gem 'benchmark-ips'
+  gem "appraisal"
+  gem "benchmark-ips"
+  gem "guard"
+  gem "guard-rspec"
+  gem "guard-rubocop"
 end
 
 group :test do
-  gem 'grape-entity', '~> 0.6'
-  gem 'maruku'
-  gem 'rack-test', '~> 0.6.3'
-  gem 'rspec', '~> 3.0'
-  gem 'cookiejar'
-  gem 'rack-jsonp', require: 'rack/jsonp'
-  gem 'mime-types'
-  gem 'ruby-grape-danger', '~> 0.1.0', require: false
-  gem 'coveralls', '~> 0.8.17', require: false
+  gem "cookiejar"
+  gem "coveralls", "~> 0.8.17", :require => false
+  gem "danger-toc", "~> 0.1.0"
+  gem "grape-entity", "~> 0.6"
+  gem "maruku"
+  gem "mime-types"
+  gem "rack-jsonp", :require => "rack/jsonp"
+  gem "rack-test", "~> 0.6.3"
+  gem "rspec", "~> 3.0"
+  gem "ruby-grape-danger", "~> 0.1.0", :require => false
 end
 
-gemspec path: '../'
+gemspec :path => "../"
diff --git a/gemfiles/rails_3.gemfile b/gemfiles/rails_3.gemfile
index 1137e17df..5b5b8ac3a 100644
--- a/gemfiles/rails_3.gemfile
+++ b/gemfiles/rails_3.gemfile
@@ -1,35 +1,36 @@
 # This file was generated by Appraisal
 
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rails', '3.2.19'
-gem 'rack-cache', '<= 1.2'
+gem "rails", "3.2.19"
+gem "rack-cache", "<= 1.2"
 
 group :development, :test do
-  gem 'bundler'
-  gem 'rake'
-  gem 'rubocop', '0.47.0'
-  gem 'hashie'
+  gem "bundler"
+  gem "hashie"
+  gem "rake"
+  gem "rubocop", "0.51.0"
 end
 
 group :development do
-  gem 'guard'
-  gem 'guard-rspec'
-  gem 'guard-rubocop'
-  gem 'appraisal'
-  gem 'benchmark-ips'
+  gem "appraisal"
+  gem "benchmark-ips"
+  gem "guard"
+  gem "guard-rspec"
+  gem "guard-rubocop"
 end
 
 group :test do
-  gem 'grape-entity', '~> 0.6'
-  gem 'maruku'
-  gem 'rack-test', '~> 0.6.3'
-  gem 'rspec', '~> 3.0'
-  gem 'cookiejar'
-  gem 'rack-jsonp', require: 'rack/jsonp'
-  gem 'mime-types'
-  gem 'ruby-grape-danger', '~> 0.1.0', require: false
-  gem 'coveralls', '~> 0.8.17', require: false
+  gem "cookiejar"
+  gem "coveralls", "~> 0.8.17", :require => false
+  gem "danger-toc", "~> 0.1.0"
+  gem "grape-entity", "~> 0.6"
+  gem "maruku"
+  gem "mime-types"
+  gem "rack-jsonp", :require => "rack/jsonp"
+  gem "rack-test", "~> 0.6.3"
+  gem "rspec", "~> 3.0"
+  gem "ruby-grape-danger", "~> 0.1.0", :require => false
 end
 
-gemspec path: '../'
+gemspec :path => "../"
diff --git a/gemfiles/rails_4.gemfile b/gemfiles/rails_4.gemfile
index e115c6cb9..d0b4262cd 100644
--- a/gemfiles/rails_4.gemfile
+++ b/gemfiles/rails_4.gemfile
@@ -1,34 +1,35 @@
 # This file was generated by Appraisal
 
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rails', '4.1.6'
+gem "rails", "4.1.6"
 
 group :development, :test do
-  gem 'bundler'
-  gem 'rake'
-  gem 'rubocop', '0.47.0'
-  gem 'hashie'
+  gem "bundler"
+  gem "hashie"
+  gem "rake"
+  gem "rubocop", "0.51.0"
 end
 
 group :development do
-  gem 'guard'
-  gem 'guard-rspec'
-  gem 'guard-rubocop'
-  gem 'appraisal'
-  gem 'benchmark-ips'
+  gem "appraisal"
+  gem "benchmark-ips"
+  gem "guard"
+  gem "guard-rspec"
+  gem "guard-rubocop"
 end
 
 group :test do
-  gem 'grape-entity', '~> 0.6'
-  gem 'maruku'
-  gem 'rack-test', '~> 0.6.3'
-  gem 'rspec', '~> 3.0'
-  gem 'cookiejar'
-  gem 'rack-jsonp', require: 'rack/jsonp'
-  gem 'mime-types'
-  gem 'ruby-grape-danger', '~> 0.1.0', require: false
-  gem 'coveralls', '~> 0.8.17', require: false
+  gem "cookiejar"
+  gem "coveralls", "~> 0.8.17", :require => false
+  gem "danger-toc", "~> 0.1.0"
+  gem "grape-entity", "~> 0.6"
+  gem "maruku"
+  gem "mime-types"
+  gem "rack-jsonp", :require => "rack/jsonp"
+  gem "rack-test", "~> 0.6.3"
+  gem "rspec", "~> 3.0"
+  gem "ruby-grape-danger", "~> 0.1.0", :require => false
 end
 
-gemspec path: '../'
+gemspec :path => "../"
diff --git a/gemfiles/rails_5.gemfile b/gemfiles/rails_5.gemfile
index a477347e9..f374975ed 100644
--- a/gemfiles/rails_5.gemfile
+++ b/gemfiles/rails_5.gemfile
@@ -1,34 +1,35 @@
 # This file was generated by Appraisal
 
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rails', '5.0.0'
+gem "rails", "5.0.0"
 
 group :development, :test do
-  gem 'bundler'
-  gem 'rake'
-  gem 'rubocop', '0.47.0'
-  gem 'hashie'
+  gem "bundler"
+  gem "hashie"
+  gem "rake"
+  gem "rubocop", "0.51.0"
 end
 
 group :development do
-  gem 'guard'
-  gem 'guard-rspec'
-  gem 'guard-rubocop'
-  gem 'appraisal'
-  gem 'benchmark-ips'
+  gem "appraisal"
+  gem "benchmark-ips"
+  gem "guard"
+  gem "guard-rspec"
+  gem "guard-rubocop"
 end
 
 group :test do
-  gem 'grape-entity', '~> 0.6'
-  gem 'maruku'
-  gem 'rack-test', '~> 0.6.3'
-  gem 'rspec', '~> 3.0'
-  gem 'cookiejar'
-  gem 'rack-jsonp', require: 'rack/jsonp'
-  gem 'mime-types'
-  gem 'ruby-grape-danger', '~> 0.1.0', require: false
-  gem 'coveralls', '~> 0.8.17', require: false
+  gem "cookiejar"
+  gem "coveralls", "~> 0.8.17", :require => false
+  gem "danger-toc", "~> 0.1.0"
+  gem "grape-entity", "~> 0.6"
+  gem "maruku"
+  gem "mime-types"
+  gem "rack-jsonp", :require => "rack/jsonp"
+  gem "rack-test", "~> 0.6.3"
+  gem "rspec", "~> 3.0"
+  gem "ruby-grape-danger", "~> 0.1.0", :require => false
 end
 
-gemspec path: '../'
+gemspec :path => "../"
diff --git a/gemfiles/rails_edge.gemfile b/gemfiles/rails_edge.gemfile
index 0b788b331..f8a5f8d71 100644
--- a/gemfiles/rails_edge.gemfile
+++ b/gemfiles/rails_edge.gemfile
@@ -1,34 +1,35 @@
 # This file was generated by Appraisal
 
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'arel', github: 'rails/arel'
+gem "arel", :github => "rails/arel"
 
 group :development, :test do
-  gem 'bundler'
-  gem 'rake'
-  gem 'rubocop', '0.47.0'
-  gem 'hashie'
+  gem "bundler"
+  gem "hashie"
+  gem "rake"
+  gem "rubocop", "0.51.0"
 end
 
 group :development do
-  gem 'guard'
-  gem 'guard-rspec'
-  gem 'guard-rubocop'
-  gem 'appraisal'
-  gem 'benchmark-ips'
+  gem "appraisal"
+  gem "benchmark-ips"
+  gem "guard"
+  gem "guard-rspec"
+  gem "guard-rubocop"
 end
 
 group :test do
-  gem 'grape-entity', '~> 0.6'
-  gem 'maruku'
-  gem 'rack-test', '~> 0.6.3'
-  gem 'rspec', '~> 3.0'
-  gem 'cookiejar'
-  gem 'rack-jsonp', require: 'rack/jsonp'
-  gem 'mime-types'
-  gem 'ruby-grape-danger', '~> 0.1.0', require: false
-  gem 'coveralls', '~> 0.8.17', require: false
+  gem "cookiejar"
+  gem "coveralls", "~> 0.8.17", :require => false
+  gem "danger-toc", "~> 0.1.0"
+  gem "grape-entity", "~> 0.6"
+  gem "maruku"
+  gem "mime-types"
+  gem "rack-jsonp", :require => "rack/jsonp"
+  gem "rack-test", "~> 0.6.3"
+  gem "rspec", "~> 3.0"
+  gem "ruby-grape-danger", "~> 0.1.0", :require => false
 end
 
-gemspec path: '../'
+gemspec :path => "../"
diff --git a/grape.gemspec b/grape.gemspec
index e2f43592a..176efd1f7 100644
--- a/grape.gemspec
+++ b/grape.gemspec
@@ -12,12 +12,12 @@ Gem::Specification.new do |s|
   s.description = 'A Ruby framework for rapid API development with great conventions.'
   s.license     = 'MIT'
 
-  s.add_runtime_dependency 'rack', '>= 1.3.0'
+  s.add_runtime_dependency 'activesupport'
+  s.add_runtime_dependency 'builder'
   s.add_runtime_dependency 'mustermann-grape', '~> 1.0.0'
+  s.add_runtime_dependency 'rack', '>= 1.3.0'
   s.add_runtime_dependency 'rack-accept'
-  s.add_runtime_dependency 'activesupport'
   s.add_runtime_dependency 'virtus', '>= 1.0.0'
-  s.add_runtime_dependency 'builder'
 
   s.files         = Dir['**/*'].keep_if { |file| File.file?(file) }
   s.test_files    = Dir['spec/**/*']
diff --git a/lib/grape/api.rb b/lib/grape/api.rb
index 4e4f79bd7..70114859d 100644
--- a/lib/grape/api.rb
+++ b/lib/grape/api.rb
@@ -161,7 +161,7 @@ def add_head_not_allowed_methods_and_options_methods
           route_settings[:endpoint] = route.app
 
           # using the :any shorthand produces [nil] for route methods, substitute all manually
-          route_settings[:methods] = %w(GET PUT POST DELETE PATCH HEAD OPTIONS) if route_settings[:methods].include?('*')
+          route_settings[:methods] = %w[GET PUT POST DELETE PATCH HEAD OPTIONS] if route_settings[:methods].include?('*')
         end
       end
 
@@ -195,7 +195,7 @@ def add_head_not_allowed_methods_and_options_methods
     # Generate a route that returns an HTTP 405 response for a user defined
     # path on methods not specified
     def generate_not_allowed_method(pattern, allowed_methods: [], **attributes)
-      not_allowed_methods = %w(GET PUT POST DELETE PATCH HEAD) - allowed_methods
+      not_allowed_methods = %w[GET PUT POST DELETE PATCH HEAD] - allowed_methods
       not_allowed_methods << Grape::Http::Headers::OPTIONS if self.class.namespace_inheritable(:do_not_route_options)
 
       return if not_allowed_methods.empty?
diff --git a/lib/grape/dsl/routing.rb b/lib/grape/dsl/routing.rb
index 2f3236d7d..fcde3dbda 100644
--- a/lib/grape/dsl/routing.rb
+++ b/lib/grape/dsl/routing.rb
@@ -136,7 +136,7 @@ def route(methods, paths = ['/'], route_options = {}, &block)
           reset_validations!
         end
 
-        %w(get post put head delete options patch).each do |meth|
+        %w[get post put head delete options patch].each do |meth|
           define_method meth do |*args, &block|
             options = args.extract_options!
             paths = args.first || ['/']
diff --git a/lib/grape/exceptions/incompatible_option_values.rb b/lib/grape/exceptions/incompatible_option_values.rb
index 5f42ea43a..a5e40b5b4 100644
--- a/lib/grape/exceptions/incompatible_option_values.rb
+++ b/lib/grape/exceptions/incompatible_option_values.rb
@@ -1,4 +1,4 @@
-# encoding: utf-8
+
 module Grape
   module Exceptions
     class IncompatibleOptionValues < Base
diff --git a/lib/grape/exceptions/invalid_accept_header.rb b/lib/grape/exceptions/invalid_accept_header.rb
index 544201607..d9e04cc89 100644
--- a/lib/grape/exceptions/invalid_accept_header.rb
+++ b/lib/grape/exceptions/invalid_accept_header.rb
@@ -1,4 +1,4 @@
-# encoding: utf-8
+
 module Grape
   module Exceptions
     class InvalidAcceptHeader < Base
diff --git a/lib/grape/exceptions/invalid_formatter.rb b/lib/grape/exceptions/invalid_formatter.rb
index 5d069b91f..21f1a473f 100644
--- a/lib/grape/exceptions/invalid_formatter.rb
+++ b/lib/grape/exceptions/invalid_formatter.rb
@@ -1,4 +1,4 @@
-# encoding: utf-8
+
 module Grape
   module Exceptions
     class InvalidFormatter < Base
diff --git a/lib/grape/exceptions/invalid_message_body.rb b/lib/grape/exceptions/invalid_message_body.rb
index c0f05281e..6c2ae2b26 100644
--- a/lib/grape/exceptions/invalid_message_body.rb
+++ b/lib/grape/exceptions/invalid_message_body.rb
@@ -1,4 +1,4 @@
-# encoding: utf-8
+
 module Grape
   module Exceptions
     class InvalidMessageBody < Base
diff --git a/lib/grape/exceptions/invalid_version_header.rb b/lib/grape/exceptions/invalid_version_header.rb
index 6b93ea7e9..7a903eebb 100644
--- a/lib/grape/exceptions/invalid_version_header.rb
+++ b/lib/grape/exceptions/invalid_version_header.rb
@@ -1,4 +1,4 @@
-# encoding: utf-8
+
 module Grape
   module Exceptions
     class InvalidVersionHeader < Base
diff --git a/lib/grape/exceptions/invalid_versioner_option.rb b/lib/grape/exceptions/invalid_versioner_option.rb
index 14aea1684..8549a3fc2 100644
--- a/lib/grape/exceptions/invalid_versioner_option.rb
+++ b/lib/grape/exceptions/invalid_versioner_option.rb
@@ -1,4 +1,4 @@
-# encoding: utf-8
+
 module Grape
   module Exceptions
     class InvalidVersionerOption < Base
diff --git a/lib/grape/exceptions/invalid_with_option_for_represent.rb b/lib/grape/exceptions/invalid_with_option_for_represent.rb
index 521a1e019..3d8530348 100644
--- a/lib/grape/exceptions/invalid_with_option_for_represent.rb
+++ b/lib/grape/exceptions/invalid_with_option_for_represent.rb
@@ -1,4 +1,4 @@
-# encoding: utf-8
+
 module Grape
   module Exceptions
     class InvalidWithOptionForRepresent < Base
diff --git a/lib/grape/exceptions/method_not_allowed.rb b/lib/grape/exceptions/method_not_allowed.rb
index 378cf034c..2fc1fd91d 100644
--- a/lib/grape/exceptions/method_not_allowed.rb
+++ b/lib/grape/exceptions/method_not_allowed.rb
@@ -1,4 +1,4 @@
-# encoding: utf-8
+
 module Grape
   module Exceptions
     class MethodNotAllowed < Base
diff --git a/lib/grape/exceptions/missing_group_type.rb b/lib/grape/exceptions/missing_group_type.rb
index 31faa6887..96ce63a98 100644
--- a/lib/grape/exceptions/missing_group_type.rb
+++ b/lib/grape/exceptions/missing_group_type.rb
@@ -1,4 +1,4 @@
-# encoding: utf-8
+
 module Grape
   module Exceptions
     class MissingGroupTypeError < Base
diff --git a/lib/grape/exceptions/missing_mime_type.rb b/lib/grape/exceptions/missing_mime_type.rb
index faaef5b53..880ba310a 100644
--- a/lib/grape/exceptions/missing_mime_type.rb
+++ b/lib/grape/exceptions/missing_mime_type.rb
@@ -1,4 +1,4 @@
-# encoding: utf-8
+
 module Grape
   module Exceptions
     class MissingMimeType < Base
diff --git a/lib/grape/exceptions/missing_option.rb b/lib/grape/exceptions/missing_option.rb
index 19d2aa61d..fad838dd1 100644
--- a/lib/grape/exceptions/missing_option.rb
+++ b/lib/grape/exceptions/missing_option.rb
@@ -1,4 +1,4 @@
-# encoding: utf-8
+
 module Grape
   module Exceptions
     class MissingOption < Base
diff --git a/lib/grape/exceptions/missing_vendor_option.rb b/lib/grape/exceptions/missing_vendor_option.rb
index b30ec42c6..a06110c8c 100644
--- a/lib/grape/exceptions/missing_vendor_option.rb
+++ b/lib/grape/exceptions/missing_vendor_option.rb
@@ -1,4 +1,4 @@
-# encoding: utf-8
+
 module Grape
   module Exceptions
     class MissingVendorOption < Base
diff --git a/lib/grape/exceptions/unknown_options.rb b/lib/grape/exceptions/unknown_options.rb
index fc92fab79..4e5d535e0 100644
--- a/lib/grape/exceptions/unknown_options.rb
+++ b/lib/grape/exceptions/unknown_options.rb
@@ -1,4 +1,4 @@
-# encoding: utf-8
+
 module Grape
   module Exceptions
     class UnknownOptions < Base
diff --git a/lib/grape/exceptions/unknown_parameter.rb b/lib/grape/exceptions/unknown_parameter.rb
index 7ed3b19af..30e8ef111 100644
--- a/lib/grape/exceptions/unknown_parameter.rb
+++ b/lib/grape/exceptions/unknown_parameter.rb
@@ -1,4 +1,4 @@
-# encoding: utf-8
+
 module Grape
   module Exceptions
     class UnknownParameter < Base
diff --git a/lib/grape/exceptions/unknown_validator.rb b/lib/grape/exceptions/unknown_validator.rb
index 3a6bf4220..3acea5304 100644
--- a/lib/grape/exceptions/unknown_validator.rb
+++ b/lib/grape/exceptions/unknown_validator.rb
@@ -1,4 +1,4 @@
-# encoding: utf-8
+
 module Grape
   module Exceptions
     class UnknownValidator < Base
diff --git a/lib/grape/exceptions/unsupported_group_type.rb b/lib/grape/exceptions/unsupported_group_type.rb
index 2ebada66e..36dfc2fc4 100644
--- a/lib/grape/exceptions/unsupported_group_type.rb
+++ b/lib/grape/exceptions/unsupported_group_type.rb
@@ -1,4 +1,4 @@
-# encoding: utf-8
+
 module Grape
   module Exceptions
     class UnsupportedGroupTypeError < Base
diff --git a/lib/grape/router/pattern.rb b/lib/grape/router/pattern.rb
index c563b76e2..9f326ecc0 100644
--- a/lib/grape/router/pattern.rb
+++ b/lib/grape/router/pattern.rb
@@ -5,7 +5,7 @@ module Grape
   class Router
     class Pattern
       DEFAULT_PATTERN_OPTIONS   = { uri_decode: true, type: :grape }.freeze
-      DEFAULT_SUPPORTED_CAPTURE = [:format, :version].freeze
+      DEFAULT_SUPPORTED_CAPTURE = %i[format version].freeze
 
       attr_reader :origin, :path, :capture, :pattern
 
diff --git a/lib/grape/router/route.rb b/lib/grape/router/route.rb
index 9026665a3..bf6e47b88 100644
--- a/lib/grape/router/route.rb
+++ b/lib/grape/router/route.rb
@@ -8,7 +8,7 @@ class Router
     class Route
       ROUTE_ATTRIBUTE_REGEXP = /route_([_a-zA-Z]\w*)/
       SOURCE_LOCATION_REGEXP = /^(.*?):(\d+?)(?::in `.+?')?$/
-      FIXED_NAMED_CAPTURES = %w(format version).freeze
+      FIXED_NAMED_CAPTURES = %w[format version].freeze
 
       attr_accessor :pattern, :translator, :app, :index, :regexp, :options
 
@@ -32,19 +32,19 @@ def respond_to_missing?(method_id, _)
         ROUTE_ATTRIBUTE_REGEXP.match(method_id.to_s)
       end
 
-      [
-        :prefix,
-        :version,
-        :settings,
-        :format,
-        :description,
-        :http_codes,
-        :headers,
-        :entity,
-        :details,
-        :requirements,
-        :request_method,
-        :namespace
+      %i[
+        prefix
+        version
+        settings
+        format
+        description
+        http_codes
+        headers
+        entity
+        details
+        requirements
+        request_method
+        namespace
       ].each do |method_name|
         define_method method_name do
           attributes.public_send method_name
diff --git a/lib/grape/validations/validators/allow_blank.rb b/lib/grape/validations/validators/allow_blank.rb
index e22a511cb..d0c314e7a 100644
--- a/lib/grape/validations/validators/allow_blank.rb
+++ b/lib/grape/validations/validators/allow_blank.rb
@@ -7,7 +7,7 @@ def validate_param!(attr_name, params)
         value = params[attr_name]
         value = value.strip if value.respond_to?(:strip)
 
-        return if false == value || value.present?
+        return if value == false || value.present?
 
         raise Grape::Exceptions::Validation, params: [@scope.full_name(attr_name)], message: message(:blank)
       end
diff --git a/spec/grape/api_spec.rb b/spec/grape/api_spec.rb
index 9b5db5a47..48bb0f415 100644
--- a/spec/grape/api_spec.rb
+++ b/spec/grape/api_spec.rb
@@ -209,7 +209,7 @@ def app
       expect(last_response.body).to eq('outer')
     end
 
-    %w(group resource resources segment).each do |als|
+    %w[group resource resources segment].each do |als|
       it "`.#{als}` is an alias" do
         inner_namespace = nil
         subject.send(als, :awesome) do
@@ -318,7 +318,7 @@ def subject.enable_root_route!
         end
 
         context 'when array of versions provided' do
-          let(:version) { %w(v1 v2) }
+          let(:version) { %w[v1 v2] }
 
           it { versioned_get '/', 'v1', using: :path }
           it { versioned_get '/', 'v2', using: :path }
@@ -333,7 +333,7 @@ def subject.enable_root_route!
       end
 
       it 'header versioned APIs with multiple headers' do
-        subject.version %w(v1 v2), using: :header, vendor: 'test'
+        subject.version %w[v1 v2], using: :header, vendor: 'test'
         subject.enable_root_route!
 
         versioned_get '/', 'v1', using: :header, vendor: 'test'
@@ -421,7 +421,7 @@ class DummyFormatClass
     end
 
     it 'allows for multiple verbs' do
-      subject.route([:get, :post], '/abc') do
+      subject.route(%i[get post], '/abc') do
         'hiya'
       end
 
@@ -435,7 +435,7 @@ class DummyFormatClass
       expect(last_response.body).to eql 'hiya'
     end
 
-    [:put, :post].each do |verb|
+    %i[put post].each do |verb|
       context verb do
         ['string', :symbol, 1, -1.1, {}, [], true, false, nil].each do |object|
           it "allows a(n) #{object.class} json object in params" do
@@ -473,14 +473,14 @@ class DummyFormatClass
     end
 
     it 'allows for multipart paths' do
-      subject.route([:get, :post], '/:id/first') do
+      subject.route(%i[get post], '/:id/first') do
         'first'
       end
 
-      subject.route([:get, :post], '/:id') do
+      subject.route(%i[get post], '/:id') do
         'ola'
       end
-      subject.route([:get, :post], '/:id/first/second') do
+      subject.route(%i[get post], '/:id/first/second') do
         'second'
       end
 
@@ -501,7 +501,7 @@ class DummyFormatClass
         'lol'
       end
 
-      %w(get post put delete options patch).each do |m|
+      %w[get post put delete options patch].each do |m|
         send(m, '/abc')
         expect(last_response.body).to eql 'lol'
       end
@@ -538,7 +538,7 @@ class DummyFormatClass
       expect(last_response.body).to eql 'catch-all'
     end
 
-    verbs = %w(post get head delete put options patch)
+    verbs = %w[post get head delete put options patch]
     verbs.each do |verb|
       it "allows and properly constrain a #{verb.upcase} method" do
         subject.send(verb, '/example') do
@@ -2393,7 +2393,7 @@ def static
         expect(subject.version).to eq('v2')
       end
       it 'returns versions' do
-        expect(subject.versions).to eq(%w(v1 v2))
+        expect(subject.versions).to eq(%w[v1 v2])
       end
       it 'sets route paths' do
         expect(subject.routes.size).to be >= 2
@@ -3368,7 +3368,7 @@ def serializable_hash
       end
       it 'array' do
         subject.get '/example' do
-          %w(example1 example2)
+          %w[example1 example2]
         end
         get '/example'
         expect(last_response.status).to eq(200)
diff --git a/spec/grape/dsl/inside_route_spec.rb b/spec/grape/dsl/inside_route_spec.rb
index f48ba0d8b..928510f75 100644
--- a/spec/grape/dsl/inside_route_spec.rb
+++ b/spec/grape/dsl/inside_route_spec.rb
@@ -91,7 +91,7 @@ def initialize
   end
 
   describe '#status' do
-    %w(GET PUT OPTIONS).each do |method|
+    %w[GET PUT OPTIONS].each do |method|
       it 'defaults to 200 on GET' do
         request = Grape::Request.new(Rack::MockRequest.env_for('/', method: method))
         expect(subject).to receive(:request).and_return(request)
diff --git a/spec/grape/dsl/parameters_spec.rb b/spec/grape/dsl/parameters_spec.rb
index f6ffd433b..27af242a2 100644
--- a/spec/grape/dsl/parameters_spec.rb
+++ b/spec/grape/dsl/parameters_spec.rb
@@ -110,7 +110,7 @@ def extract_message_option(attrs)
         it 'adds an mutally exclusive parameter validation' do
           subject.mutually_exclusive :media, :audio
 
-          expect(subject.validates_reader).to eq([[:media, :audio], { mutual_exclusion: { value: true, message: nil } }])
+          expect(subject.validates_reader).to eq([%i[media audio], { mutual_exclusion: { value: true, message: nil } }])
         end
       end
 
@@ -118,7 +118,7 @@ def extract_message_option(attrs)
         it 'adds an exactly of one parameter validation' do
           subject.exactly_one_of :media, :audio
 
-          expect(subject.validates_reader).to eq([[:media, :audio], { exactly_one_of: { value: true, message: nil } }])
+          expect(subject.validates_reader).to eq([%i[media audio], { exactly_one_of: { value: true, message: nil } }])
         end
       end
 
@@ -126,7 +126,7 @@ def extract_message_option(attrs)
         it 'adds an at least one of parameter validation' do
           subject.at_least_one_of :media, :audio
 
-          expect(subject.validates_reader).to eq([[:media, :audio], { at_least_one_of: { value: true, message: nil } }])
+          expect(subject.validates_reader).to eq([%i[media audio], { at_least_one_of: { value: true, message: nil } }])
         end
       end
 
@@ -134,7 +134,7 @@ def extract_message_option(attrs)
         it 'adds an all or none of parameter validation' do
           subject.all_or_none_of :media, :audio
 
-          expect(subject.validates_reader).to eq([[:media, :audio], { all_or_none_of: { value: true, message: nil } }])
+          expect(subject.validates_reader).to eq([%i[media audio], { all_or_none_of: { value: true, message: nil } }])
         end
       end
 
@@ -155,7 +155,7 @@ def extract_message_option(attrs)
         describe 'when params argument is an array of hashes' do
           it 'returns values of each hash for @element key' do
             subject.element = :foo
-            expect(subject.params([{ foo: 'bar' }, { foo: 'baz' }])).to eq(%w(bar baz))
+            expect(subject.params([{ foo: 'bar' }, { foo: 'baz' }])).to eq(%w[bar baz])
           end
         end
 
diff --git a/spec/grape/dsl/settings_spec.rb b/spec/grape/dsl/settings_spec.rb
index 556e353ff..1620c4f7d 100644
--- a/spec/grape/dsl/settings_spec.rb
+++ b/spec/grape/dsl/settings_spec.rb
@@ -166,7 +166,7 @@ def reset_validations!; end
 
           subject.namespace_stackable(:some_thing, :foo_bar_2)
 
-          expect(subject.namespace_stackable(:some_thing)).to eq [:foo_bar, :foo_bar_2]
+          expect(subject.namespace_stackable(:some_thing)).to eq %i[foo_bar foo_bar_2]
 
           subject.namespace_end
           expect(subject.namespace_stackable(:some_thing)).to eq [:foo_bar]
@@ -253,7 +253,7 @@ def reset_validations!; end
           obj1.top_level_setting.inherit_from obj2_copy.point_in_time_copy
           obj2.top_level_setting.inherit_from obj3_copy.point_in_time_copy
 
-          expect(obj1_copy.namespace_stackable[:some_thing]).to eq [:obj3, :obj2, :obj1]
+          expect(obj1_copy.namespace_stackable[:some_thing]).to eq %i[obj3 obj2 obj1]
         end
       end
     end
diff --git a/spec/grape/endpoint_spec.rb b/spec/grape/endpoint_spec.rb
index dbe1d2cab..659766f2a 100644
--- a/spec/grape/endpoint_spec.rb
+++ b/spec/grape/endpoint_spec.rb
@@ -215,7 +215,7 @@ def app
         [cookie.name, cookie]
       end]
       expect(cookies.size).to eq(2)
-      %w(and_this delete_this_cookie).each do |cookie_name|
+      %w[and_this delete_this_cookie].each do |cookie_name|
         cookie = cookies[cookie_name]
         expect(cookie).not_to be_nil
         expect(cookie.value).to eq('deleted')
@@ -239,7 +239,7 @@ def app
         [cookie.name, cookie]
       end]
       expect(cookies.size).to eq(2)
-      %w(and_this delete_this_cookie).each do |cookie_name|
+      %w[and_this delete_this_cookie].each do |cookie_name|
         cookie = cookies[cookie_name]
         expect(cookie).not_to be_nil
         expect(cookie.value).to eq('deleted')
@@ -528,9 +528,9 @@ def app
       json = JSON.parse(last_response.body)
       expect(last_response.status).to eq(200)
       expect(json['first']).to eq 'present'
-      expect(json['nested'].keys).to eq %w(fourth fifth nested_nested)
+      expect(json['nested'].keys).to eq %w[fourth fifth nested_nested]
       expect(json['nested']['fourth']).to eq ''
-      expect(json['nested']['nested_nested'].keys).to eq %w(sixth seven)
+      expect(json['nested']['nested_nested'].keys).to eq %w[sixth seven]
       expect(json['nested']['nested_nested']['sixth']).to eq 'sixth'
     end
 
@@ -556,7 +556,7 @@ def app
       json = JSON.parse(last_response.body)
       expect(last_response.status).to eq(200)
       expect(json['first']).to eq 'present'
-      expect(json['nested'].keys).to eq %w(fourth)
+      expect(json['nested'].keys).to eq %w[fourth]
       expect(json['nested']['fourth']).to eq '4'
     end
   end
@@ -1224,7 +1224,7 @@ def memoized
 
       get '/all_filters'
       json = JSON.parse(last_response.body)
-      expect(json.keys).to match_array %w(before before_validation after_validation endpoint after)
+      expect(json.keys).to match_array %w[before before_validation after_validation endpoint after]
     end
 
     context 'when terminating the response with error!' do
@@ -1241,7 +1241,7 @@ def memoized
 
         get '/error_filters'
         expect(last_response.status).to eql 500
-        expect(called).to match_array %w(before before_validation)
+        expect(called).to match_array %w[before before_validation]
       end
 
       it 'allows prior and parent filters of same type to run' do
@@ -1259,7 +1259,7 @@ def memoized
 
         get '/parent/hello'
         expect(last_response.status).to eql 500
-        expect(called).to match_array %w(parent prior)
+        expect(called).to match_array %w[parent prior]
       end
     end
   end
@@ -1326,7 +1326,7 @@ def memoized
     end
 
     describe 'all other' do
-      %w(post get head put options patch).each do |verb|
+      %w[post get head put options patch].each do |verb|
         it "allows for the anchoring option with a #{verb.upcase} method" do
           subject.send(verb, '/example', anchor: true) do
             verb
diff --git a/spec/grape/entity_spec.rb b/spec/grape/entity_spec.rb
index 4748d1467..35299dfb9 100644
--- a/spec/grape/entity_spec.rb
+++ b/spec/grape/entity_spec.rb
@@ -169,7 +169,7 @@ def first
       expect(inner_body).to eql(root: { abc: 'def' })
     end
 
-    [:json, :serializable_hash].each do |format|
+    %i[json serializable_hash].each do |format|
       it "presents with #{format}" do
         entity = Class.new(Grape::Entity)
         entity.root 'examples', 'example'
diff --git a/spec/grape/exceptions/invalid_formatter_spec.rb b/spec/grape/exceptions/invalid_formatter_spec.rb
index e98ab75a6..01ac0439b 100644
--- a/spec/grape/exceptions/invalid_formatter_spec.rb
+++ b/spec/grape/exceptions/invalid_formatter_spec.rb
@@ -1,4 +1,4 @@
-# encoding: utf-8
+
 require 'spec_helper'
 
 describe Grape::Exceptions::InvalidFormatter do
diff --git a/spec/grape/exceptions/invalid_versioner_option_spec.rb b/spec/grape/exceptions/invalid_versioner_option_spec.rb
index 1e0dde002..2778b793f 100644
--- a/spec/grape/exceptions/invalid_versioner_option_spec.rb
+++ b/spec/grape/exceptions/invalid_versioner_option_spec.rb
@@ -1,4 +1,4 @@
-# encoding: utf-8
+
 require 'spec_helper'
 
 describe Grape::Exceptions::InvalidVersionerOption do
diff --git a/spec/grape/exceptions/missing_option_spec.rb b/spec/grape/exceptions/missing_option_spec.rb
index 2aaac32cd..54e750695 100644
--- a/spec/grape/exceptions/missing_option_spec.rb
+++ b/spec/grape/exceptions/missing_option_spec.rb
@@ -1,4 +1,4 @@
-# encoding: utf-8
+
 require 'spec_helper'
 
 describe Grape::Exceptions::MissingOption do
diff --git a/spec/grape/exceptions/unknown_options_spec.rb b/spec/grape/exceptions/unknown_options_spec.rb
index ca49321c4..c94e81c9f 100644
--- a/spec/grape/exceptions/unknown_options_spec.rb
+++ b/spec/grape/exceptions/unknown_options_spec.rb
@@ -1,10 +1,10 @@
-# encoding: utf-8
+
 require 'spec_helper'
 
 describe Grape::Exceptions::UnknownOptions do
   describe '#message' do
     let(:error) do
-      described_class.new([:a, :b])
+      described_class.new(%i[a b])
     end
 
     it 'contains the problem in the message' do
diff --git a/spec/grape/exceptions/unknown_validator_spec.rb b/spec/grape/exceptions/unknown_validator_spec.rb
index 8015ba9fd..9411b50c0 100644
--- a/spec/grape/exceptions/unknown_validator_spec.rb
+++ b/spec/grape/exceptions/unknown_validator_spec.rb
@@ -1,4 +1,4 @@
-# encoding: utf-8
+
 require 'spec_helper'
 
 describe Grape::Exceptions::UnknownValidator do
diff --git a/spec/grape/exceptions/validation_errors_spec.rb b/spec/grape/exceptions/validation_errors_spec.rb
index e0ee3883b..bbbcc10cc 100644
--- a/spec/grape/exceptions/validation_errors_spec.rb
+++ b/spec/grape/exceptions/validation_errors_spec.rb
@@ -69,7 +69,7 @@ def app
       get '/exactly_one_of', beer: 'string', wine: 'anotherstring'
       expect(last_response.status).to eq(400)
       expect(JSON.parse(last_response.body)).to eq([
-                                                     'params' => %w(beer wine),
+                                                     'params' => %w[beer wine],
                                                      'messages' => ['are mutually exclusive']
                                                    ])
     end
diff --git a/spec/grape/middleware/formatter_spec.rb b/spec/grape/middleware/formatter_spec.rb
index aeab1c4e1..dafef25a8 100644
--- a/spec/grape/middleware/formatter_spec.rb
+++ b/spec/grape/middleware/formatter_spec.rb
@@ -223,7 +223,7 @@ def to_xml
   end
 
   context 'input' do
-    %w(POST PATCH PUT DELETE).each do |method|
+    %w[POST PATCH PUT DELETE].each do |method|
       ['application/json', 'application/json; charset=utf-8'].each do |content_type|
         context content_type do
           it "parses the body from #{method} and copies values into rack.request.form_hash" do
diff --git a/spec/grape/middleware/versioner/header_spec.rb b/spec/grape/middleware/versioner/header_spec.rb
index 498fe50a6..5befcc6a7 100644
--- a/spec/grape/middleware/versioner/header_spec.rb
+++ b/spec/grape/middleware/versioner/header_spec.rb
@@ -241,7 +241,7 @@
 
   context 'when multiple versions are specified' do
     before do
-      @options[:versions] = %w(v1 v2)
+      @options[:versions] = %w[v1 v2]
     end
 
     it 'succeeds with v1' do
diff --git a/spec/grape/middleware/versioner/param_spec.rb b/spec/grape/middleware/versioner/param_spec.rb
index 98bb0710a..cdf3d23a8 100644
--- a/spec/grape/middleware/versioner/param_spec.rb
+++ b/spec/grape/middleware/versioner/param_spec.rb
@@ -35,7 +35,7 @@
   end
 
   context 'with specified versions' do
-    let(:options) { { versions: %w(v1 v2) } }
+    let(:options) { { versions: %w[v1 v2] } }
     it 'throws an error if a non-allowed version is specified' do
       env = Rack::MockRequest.env_for('/awesome', params: { 'apiver' => 'v3' })
       expect(catch(:error) { subject.call(env) }[:status]).to eq(404)
diff --git a/spec/grape/middleware/versioner/path_spec.rb b/spec/grape/middleware/versioner/path_spec.rb
index 686be9393..c5e9995d8 100644
--- a/spec/grape/middleware/versioner/path_spec.rb
+++ b/spec/grape/middleware/versioner/path_spec.rb
@@ -28,7 +28,7 @@
     end
   end
 
-  [%w(v1 v2), [:v1, :v2], [:v1, 'v2'], ['v1', :v2]].each do |versions|
+  [%w[v1 v2], %i[v1 v2], [:v1, 'v2'], ['v1', :v2]].each do |versions|
     context "with specified versions as #{versions}" do
       let(:options) { { versions: versions } }
 
diff --git a/spec/grape/path_spec.rb b/spec/grape/path_spec.rb
index 88ffd8793..721b69f24 100644
--- a/spec/grape/path_spec.rb
+++ b/spec/grape/path_spec.rb
@@ -31,8 +31,8 @@ module Grape
       end
 
       it 'splits the mount path' do
-        path = Path.new(anything, anything, mount_path: %w(foo bar))
-        expect(path.mount_path).to eql(%w(foo bar))
+        path = Path.new(anything, anything, mount_path: %w[foo bar])
+        expect(path.mount_path).to eql(%w[foo bar])
       end
     end
 
@@ -49,7 +49,7 @@ module Grape
 
       it 'splits the mount path' do
         path = Path.new(anything, anything, root_prefix: 'hello/world')
-        expect(path.root_prefix).to eql(%w(hello world))
+        expect(path.root_prefix).to eql(%w[hello world])
       end
     end
 
diff --git a/spec/grape/util/inheritable_setting_spec.rb b/spec/grape/util/inheritable_setting_spec.rb
index 4caa7606f..866a7bbd3 100644
--- a/spec/grape/util/inheritable_setting_spec.rb
+++ b/spec/grape/util/inheritable_setting_spec.rb
@@ -192,7 +192,7 @@ module Util
           expect(cloned_obj.namespace_stackable[:namespace_stackable_thing]).to eq [:namespace_stackable_foo_bar]
 
           subject.namespace_stackable[:namespace_stackable_thing] = :other_thing
-          expect(subject.namespace_stackable[:namespace_stackable_thing]).to eq [:namespace_stackable_foo_bar, :other_thing]
+          expect(subject.namespace_stackable[:namespace_stackable_thing]).to eq %i[namespace_stackable_foo_bar other_thing]
           expect(cloned_obj.namespace_stackable[:namespace_stackable_thing]).to eq [:namespace_stackable_foo_bar]
         end
 
@@ -200,7 +200,7 @@ module Util
           expect(cloned_obj.namespace_reverse_stackable[:namespace_reverse_stackable_thing]).to eq [:namespace_reverse_stackable_foo_bar]
 
           subject.namespace_reverse_stackable[:namespace_reverse_stackable_thing] = :other_thing
-          expect(subject.namespace_reverse_stackable[:namespace_reverse_stackable_thing]).to eq [:other_thing, :namespace_reverse_stackable_foo_bar]
+          expect(subject.namespace_reverse_stackable[:namespace_reverse_stackable_thing]).to eq %i[other_thing namespace_reverse_stackable_foo_bar]
           expect(cloned_obj.namespace_reverse_stackable[:namespace_reverse_stackable_thing]).to eq [:namespace_reverse_stackable_foo_bar]
         end
 
diff --git a/spec/grape/util/reverse_stackable_values_spec.rb b/spec/grape/util/reverse_stackable_values_spec.rb
index 2fc623664..6c2d6b543 100644
--- a/spec/grape/util/reverse_stackable_values_spec.rb
+++ b/spec/grape/util/reverse_stackable_values_spec.rb
@@ -9,7 +9,7 @@ module Util
         it 'returns all keys' do
           subject[:some_thing] = :foo_bar
           subject[:some_thing_else] = :foo_bar
-          expect(subject.keys).to eq [:some_thing, :some_thing_else].sort
+          expect(subject.keys).to eq %i[some_thing some_thing_else].sort
         end
 
         it 'returns merged keys with parent' do
@@ -19,7 +19,7 @@ module Util
           subject[:some_thing] = :foo_bar
           subject[:some_thing_more] = :foo_bar
 
-          expect(subject.keys).to eq [:some_thing, :some_thing_else, :some_thing_more].sort
+          expect(subject.keys).to eq %i[some_thing some_thing_else some_thing_more].sort
         end
       end
 
@@ -52,7 +52,7 @@ module Util
         it 'combines parent and actual values (actual first)' do
           parent[:some_thing] = :foo
           subject[:some_thing] = :foo_bar
-          expect(subject[:some_thing]).to eq [:foo_bar, :foo]
+          expect(subject[:some_thing]).to eq %i[foo_bar foo]
         end
 
         it 'parent values are not changed' do
@@ -71,28 +71,28 @@ module Util
         it 'pushes further values' do
           subject[:some_thing] = :foo
           subject[:some_thing] = :bar
-          expect(subject[:some_thing]).to eq [:foo, :bar]
+          expect(subject[:some_thing]).to eq %i[foo bar]
         end
 
         it 'can handle array values' do
           subject[:some_thing] = :foo
-          subject[:some_thing] = [:bar, :more]
-          expect(subject[:some_thing]).to eq [:foo, [:bar, :more]]
+          subject[:some_thing] = %i[bar more]
+          expect(subject[:some_thing]).to eq [:foo, %i[bar more]]
 
-          parent[:some_thing_else] = [:foo, :bar]
-          subject[:some_thing_else] = [:some, :bar, :foo]
+          parent[:some_thing_else] = %i[foo bar]
+          subject[:some_thing_else] = %i[some bar foo]
 
-          expect(subject[:some_thing_else]).to eq [[:some, :bar, :foo], [:foo, :bar]]
+          expect(subject[:some_thing_else]).to eq [%i[some bar foo], %i[foo bar]]
         end
       end
 
       describe '#to_hash' do
         it 'returns a Hash representation' do
           parent[:some_thing] = :foo
-          subject[:some_thing] = [:bar, :more]
+          subject[:some_thing] = %i[bar more]
           subject[:some_thing_more] = :foo_bar
           expect(subject.to_hash).to eq(
-            some_thing: [[:bar, :more], :foo],
+            some_thing: [%i[bar more], :foo],
             some_thing_more: [:foo_bar]
           )
         end
@@ -106,12 +106,12 @@ module Util
           grandchild = described_class.new child
 
           parent[:some_thing] = :foo
-          child[:some_thing] = [:bar, :more]
+          child[:some_thing] = %i[bar more]
           grandchild[:some_thing] = :grand_foo_bar
           grandchild[:some_thing_more] = :foo_bar
 
           expect(grandchild.clone.to_hash).to eq(
-            some_thing: [:grand_foo_bar, [:bar, :more], :foo],
+            some_thing: [:grand_foo_bar, %i[bar more], :foo],
             some_thing_more: [:foo_bar]
           )
         end
diff --git a/spec/grape/util/stackable_values_spec.rb b/spec/grape/util/stackable_values_spec.rb
index 6f2982dfb..82a327a56 100644
--- a/spec/grape/util/stackable_values_spec.rb
+++ b/spec/grape/util/stackable_values_spec.rb
@@ -9,7 +9,7 @@ module Util
         it 'returns all key' do
           subject[:some_thing] = :foo_bar
           subject[:some_thing_else] = :foo_bar
-          expect(subject.keys).to eq [:some_thing, :some_thing_else].sort
+          expect(subject.keys).to eq %i[some_thing some_thing_else].sort
         end
 
         it 'returns merged keys with parent' do
@@ -19,7 +19,7 @@ module Util
           subject[:some_thing] = :foo_bar
           subject[:some_thing_more] = :foo_bar
 
-          expect(subject.keys).to eq [:some_thing, :some_thing_else, :some_thing_more].sort
+          expect(subject.keys).to eq %i[some_thing some_thing_else some_thing_more].sort
         end
       end
 
@@ -52,7 +52,7 @@ module Util
         it 'combines parent and actual values' do
           parent[:some_thing] = :foo
           subject[:some_thing] = :foo_bar
-          expect(subject[:some_thing]).to eq [:foo, :foo_bar]
+          expect(subject[:some_thing]).to eq %i[foo foo_bar]
         end
 
         it 'parent values are not changed' do
@@ -71,27 +71,27 @@ module Util
         it 'pushes further values' do
           subject[:some_thing] = :foo
           subject[:some_thing] = :bar
-          expect(subject[:some_thing]).to eq [:foo, :bar]
+          expect(subject[:some_thing]).to eq %i[foo bar]
         end
 
         it 'can handle array values' do
           subject[:some_thing] = :foo
-          subject[:some_thing] = [:bar, :more]
-          expect(subject[:some_thing]).to eq [:foo, [:bar, :more]]
+          subject[:some_thing] = %i[bar more]
+          expect(subject[:some_thing]).to eq [:foo, %i[bar more]]
 
-          parent[:some_thing_else] = [:foo, :bar]
-          subject[:some_thing_else] = [:some, :bar, :foo]
+          parent[:some_thing_else] = %i[foo bar]
+          subject[:some_thing_else] = %i[some bar foo]
 
-          expect(subject[:some_thing_else]).to eq [[:foo, :bar], [:some, :bar, :foo]]
+          expect(subject[:some_thing_else]).to eq [%i[foo bar], %i[some bar foo]]
         end
       end
 
       describe '#to_hash' do
         it 'returns a Hash representation' do
           parent[:some_thing] = :foo
-          subject[:some_thing] = [:bar, :more]
+          subject[:some_thing] = %i[bar more]
           subject[:some_thing_more] = :foo_bar
-          expect(subject.to_hash).to eq(some_thing: [:foo, [:bar, :more]], some_thing_more: [:foo_bar])
+          expect(subject.to_hash).to eq(some_thing: [:foo, %i[bar more]], some_thing_more: [:foo_bar])
         end
       end
 
@@ -103,11 +103,11 @@ module Util
           grandchild = StackableValues.new child
 
           parent[:some_thing] = :foo
-          child[:some_thing] = [:bar, :more]
+          child[:some_thing] = %i[bar more]
           grandchild[:some_thing] = :grand_foo_bar
           grandchild[:some_thing_more] = :foo_bar
 
-          expect(grandchild.clone.to_hash).to eq(some_thing: [:foo, [:bar, :more], :grand_foo_bar], some_thing_more: [:foo_bar])
+          expect(grandchild.clone.to_hash).to eq(some_thing: [:foo, %i[bar more], :grand_foo_bar], some_thing_more: [:foo_bar])
         end
 
         context 'complex (i.e. not primitive) data types (ex. middleware, please see bug #930)' do
diff --git a/spec/grape/util/strict_hash_configuration_spec.rb b/spec/grape/util/strict_hash_configuration_spec.rb
index 428d1f5e0..8798d095f 100644
--- a/spec/grape/util/strict_hash_configuration_spec.rb
+++ b/spec/grape/util/strict_hash_configuration_spec.rb
@@ -4,7 +4,7 @@ module Util
     describe 'StrictHashConfiguration' do
       subject do
         Class.new do
-          include Grape::Util::StrictHashConfiguration.module(:config1, :config2, config3: [:config4], config5: [config6: [:config7, :config8]])
+          include Grape::Util::StrictHashConfiguration.module(:config1, :config2, config3: [:config4], config5: [config6: %i[config7 config8]])
         end
       end
 
diff --git a/spec/grape/validations/params_scope_spec.rb b/spec/grape/validations/params_scope_spec.rb
index e048496ed..075db2195 100644
--- a/spec/grape/validations/params_scope_spec.rb
+++ b/spec/grape/validations/params_scope_spec.rb
@@ -74,7 +74,7 @@ def app
   end
 
   context 'setting description' do
-    [:desc, :description].each do |description_type|
+    %i[desc description].each do |description_type|
       it "allows setting #{description_type}" do
         subject.params do
           requires :int, type: Integer, description_type => 'My very nice integer'
@@ -160,18 +160,18 @@ def initialize(value)
   context 'array without coerce type explicitly given' do
     it 'sets the type based on first element' do
       subject.params do
-        requires :periods, type: Array, values: -> { %w(day month) }
+        requires :periods, type: Array, values: -> { %w[day month] }
       end
       subject.get('/required') { 'required works' }
 
-      get '/required', periods: %w(day month)
+      get '/required', periods: %w[day month]
       expect(last_response.status).to eq(200)
       expect(last_response.body).to eq('required works')
     end
 
     it 'fails to call API without Array type' do
       subject.params do
-        requires :periods, type: Array, values: -> { %w(day month) }
+        requires :periods, type: Array, values: -> { %w[day month] }
       end
       subject.get('/required') { 'required works' }
 
@@ -468,7 +468,7 @@ def initialize(value)
 
     it 'does not validate nested requires when given is false' do
       subject.params do
-        requires :a, type: String, allow_blank: false, values: %w(x y z)
+        requires :a, type: String, allow_blank: false, values: %w[x y z]
         given a: ->(val) { val == 'x' } do
           requires :inner1, type: Hash, allow_blank: false do
             requires :foo, type: Integer, allow_blank: false
@@ -586,8 +586,8 @@ def initialize(value)
 
   context 'when validations are dependent on a parameter with specific value' do
     # build test cases from all combinations of declarations and options
-    a_decls = %i(optional requires)
-    a_options = [{}, { values: %w(x y z) }]
+    a_decls = %i[optional requires]
+    a_options = [{}, { values: %w[x y z] }]
     b_options = [{}, { type: String }, { allow_blank: false }, { type: String, allow_blank: false }]
     combinations = a_decls.product(a_options, b_options)
     combinations.each_with_index do |combination, i|
diff --git a/spec/grape/validations/validators/all_or_none_spec.rb b/spec/grape/validations/validators/all_or_none_spec.rb
index 0e6e9b40e..98d82ce8f 100644
--- a/spec/grape/validations/validators/all_or_none_spec.rb
+++ b/spec/grape/validations/validators/all_or_none_spec.rb
@@ -11,7 +11,7 @@ def params(arg)
         def required?; end
       end
     end
-    let(:all_or_none_params) { [:beer, :wine, :grapefruit] }
+    let(:all_or_none_params) { %i[beer wine grapefruit] }
     let(:validator) { described_class.new(all_or_none_params, {}, false, scope.new) }
 
     context 'when all restricted params are present' do
diff --git a/spec/grape/validations/validators/at_least_one_of_spec.rb b/spec/grape/validations/validators/at_least_one_of_spec.rb
index 6a0a05fea..7a331fe9b 100644
--- a/spec/grape/validations/validators/at_least_one_of_spec.rb
+++ b/spec/grape/validations/validators/at_least_one_of_spec.rb
@@ -11,7 +11,7 @@ def params(arg)
         def required?; end
       end
     end
-    let(:at_least_one_of_params) { [:beer, :wine, :grapefruit] }
+    let(:at_least_one_of_params) { %i[beer wine grapefruit] }
     let(:validator) { described_class.new(at_least_one_of_params, {}, false, scope.new) }
 
     context 'when all restricted params are present' do
diff --git a/spec/grape/validations/validators/coerce_spec.rb b/spec/grape/validations/validators/coerce_spec.rb
index c3eaaf0ad..b21ec8cf2 100644
--- a/spec/grape/validations/validators/coerce_spec.rb
+++ b/spec/grape/validations/validators/coerce_spec.rb
@@ -1,4 +1,4 @@
-# encoding: utf-8
+
 require 'spec_helper'
 
 describe Grape::Validations::CoerceValidator do
@@ -136,11 +136,11 @@ class User
         'array int works'
       end
 
-      get 'array', ids: %w(1 2 az)
+      get 'array', ids: %w[1 2 az]
       expect(last_response.status).to eq(400)
       expect(last_response.body).to eq('ids is invalid')
 
-      get 'array', ids: %w(1 2 890)
+      get 'array', ids: %w[1 2 890]
       expect(last_response.status).to eq(200)
       expect(last_response.body).to eq('array int works')
     end
@@ -187,7 +187,7 @@ class User
             params[:arry][0].class
           end
 
-          get '/array', arry: %w(1 2 3)
+          get '/array', arry: %w[1 2 3]
           expect(last_response.status).to eq(200)
           expect(last_response.body).to eq(integer_class_name)
         end
@@ -444,11 +444,11 @@ def self.parsed?(value)
 
         get '/ints', values: '1 2 3 4'
         expect(last_response.status).to eq(200)
-        expect(JSON.parse(last_response.body)).to eq(%w(1 2 3 4))
+        expect(JSON.parse(last_response.body)).to eq(%w[1 2 3 4])
 
         get '/ints', values: 'a b c d'
         expect(last_response.status).to eq(200)
-        expect(JSON.parse(last_response.body)).to eq(%w(0 0 0 0))
+        expect(JSON.parse(last_response.body)).to eq(%w[0 0 0 0])
       end
 
       it 'parses parameters with Array[Integer] type' do
@@ -480,7 +480,7 @@ def self.parsed?(value)
         expect(last_response.status).to eq(200)
         expect(JSON.parse(last_response.body)).to eq([2, 3, 4, 5])
 
-        get '/ints', values: %w(a b c d)
+        get '/ints', values: %w[a b c d]
         expect(last_response.status).to eq(200)
         expect(JSON.parse(last_response.body)).to eq([1, 1, 1, 1])
       end
@@ -742,7 +742,7 @@ def self.parsed?(value)
           expect(last_response.status).to eq(200)
           expect(last_response.body).to eq('"one way"')
 
-          get '/', a: %w(the other)
+          get '/', a: %w[the other]
           expect(last_response.status).to eq(200)
           expect(last_response.body).to eq('["the", "other"]')
 
@@ -760,7 +760,7 @@ def self.parsed?(value)
           expect(last_response.status).to eq(200)
           expect(last_response.body).to eq('[1, 2, 3]')
 
-          get '/', b: %w(1 2 3)
+          get '/', b: %w[1 2 3]
           expect(last_response.status).to eq(200)
           expect(last_response.body).to eq('[1, 2, 3]')
 
@@ -782,7 +782,7 @@ def self.parsed?(value)
           expect(last_response.status).to eq(200)
           expect(last_response.body).to eq('"one"')
 
-          get '/', d: %w(1 two)
+          get '/', d: %w[1 two]
           expect(last_response.status).to eq(200)
           expect(last_response.body).to eq('#<Set: {1, "two"}>')
         end
@@ -813,7 +813,7 @@ def self.parsed?(value)
             expect(last_response.status).to eq(200)
             expect(last_response.body).to eq('"one way"')
 
-            get '/', a: %w(the other)
+            get '/', a: %w[the other]
             expect(last_response.status).to eq(200)
             expect(last_response.body).to eq('#<Hashie::Array ["the", "other"]>')
 
@@ -831,7 +831,7 @@ def self.parsed?(value)
             expect(last_response.status).to eq(200)
             expect(last_response.body).to eq('#<Hashie::Array [1, 2, 3]>')
 
-            get '/', b: %w(1 2 3)
+            get '/', b: %w[1 2 3]
             expect(last_response.status).to eq(200)
             expect(last_response.body).to eq('#<Hashie::Array [1, 2, 3]>')
 
@@ -853,7 +853,7 @@ def self.parsed?(value)
             expect(last_response.status).to eq(200)
             expect(last_response.body).to eq('"one"')
 
-            get '/', d: %w(1 two)
+            get '/', d: %w[1 two]
             expect(last_response.status).to eq(200)
             expect(last_response.body).to eq('#<Set: {1, "two"}>')
           end
diff --git a/spec/grape/validations/validators/exactly_one_of_spec.rb b/spec/grape/validations/validators/exactly_one_of_spec.rb
index 166bb0627..8bdb23073 100644
--- a/spec/grape/validations/validators/exactly_one_of_spec.rb
+++ b/spec/grape/validations/validators/exactly_one_of_spec.rb
@@ -11,7 +11,7 @@ def params(arg)
         def required?; end
       end
     end
-    let(:exactly_one_of_params) { [:beer, :wine, :grapefruit] }
+    let(:exactly_one_of_params) { %i[beer wine grapefruit] }
     let(:validator) { described_class.new(exactly_one_of_params, {}, false, scope.new) }
 
     context 'when all restricted params are present' do
diff --git a/spec/grape/validations/validators/mutual_exclusion_spec.rb b/spec/grape/validations/validators/mutual_exclusion_spec.rb
index f06778054..9fa6375b5 100644
--- a/spec/grape/validations/validators/mutual_exclusion_spec.rb
+++ b/spec/grape/validations/validators/mutual_exclusion_spec.rb
@@ -9,7 +9,7 @@ def params(arg)
         end
       end
     end
-    let(:mutually_exclusive_params) { [:beer, :wine, :grapefruit] }
+    let(:mutually_exclusive_params) { %i[beer wine grapefruit] }
     let(:validator) { described_class.new(mutually_exclusive_params, {}, false, scope.new) }
 
     context 'when all mutually exclusive params are present' do
diff --git a/spec/grape/validations/validators/values_spec.rb b/spec/grape/validations/validators/values_spec.rb
index 4e7cecf07..2317cf555 100644
--- a/spec/grape/validations/validators/values_spec.rb
+++ b/spec/grape/validations/validators/values_spec.rb
@@ -159,7 +159,7 @@ class API < Grape::API
 
         params do
           optional :optional, type: Array do
-            requires :type, values: %w(a b)
+            requires :type, values: %w[a b]
           end
         end
         get '/optional_with_required_values'
@@ -207,7 +207,7 @@ class API < Grape::API
         end
 
         params do
-          optional :optional, type: Array[String], values: %w(a b c)
+          optional :optional, type: Array[String], values: %w[a b c]
         end
         put '/optional_with_array_of_string_values'
 
@@ -555,7 +555,7 @@ def app
     end
 
     it 'rejects an array of values if any of them matches except' do
-      get '/except/exclusive', type: %w(valid1 valid2 invalid-type1 valid4)
+      get '/except/exclusive', type: %w[valid1 valid2 invalid-type1 valid4]
       expect(last_response.status).to eq 400
       expect(last_response.body).to eq({ error: 'type has a value not allowed' }.to_json)
     end
diff --git a/spec/grape/validations_spec.rb b/spec/grape/validations_spec.rb
index 2c5e90e58..a5b79be9e 100644
--- a/spec/grape/validations_spec.rb
+++ b/spec/grape/validations_spec.rb
@@ -63,7 +63,7 @@ def define_optional_using
 
       it 'adds entity documentation to declared params' do
         define_optional_using
-        expect(subject.route_setting(:declared_params)).to eq([:field_a, :field_b])
+        expect(subject.route_setting(:declared_params)).to eq(%i[field_a field_b])
       end
 
       it 'works when field_a and field_b are not present' do
@@ -139,7 +139,7 @@ def define_requires_all
 
       it 'adds entity documentation to declared params' do
         define_requires_all
-        expect(subject.route_setting(:declared_params)).to eq([:required_field, :optional_field])
+        expect(subject.route_setting(:declared_params)).to eq(%i[required_field optional_field])
       end
 
       it 'errors when required_field is not present' do
@@ -174,7 +174,7 @@ def define_requires_none
 
       it 'adds entity documentation to declared params' do
         define_requires_none
-        expect(subject.route_setting(:declared_params)).to eq([:required_field, :optional_field])
+        expect(subject.route_setting(:declared_params)).to eq(%i[required_field optional_field])
       end
 
       it 'errors when required_field is not present' do
@@ -204,7 +204,7 @@ def define_requires_all
 
         it 'adds only the entity documentation to declared params, nothing more' do
           define_requires_all
-          expect(subject.route_setting(:declared_params)).to eq([:required_field, :optional_field])
+          expect(subject.route_setting(:declared_params)).to eq(%i[required_field optional_field])
         end
       end
 
@@ -350,7 +350,7 @@ def define_requires_none
       before do
         subject.params do
           requires :items, type: Hash do
-            requires :key, type: String, values: %w(a b)
+            requires :key, type: String, values: %w[a b]
           end
         end
         subject.get '/required' do
@@ -1058,14 +1058,14 @@ def validate_param!(attr_name, params)
           subject.params do
             use :pagination
           end
-          expect(subject.route_setting(:declared_params)).to eq [:page, :per_page]
+          expect(subject.route_setting(:declared_params)).to eq %i[page per_page]
         end
 
         it 'by #use with multiple params' do
           subject.params do
             use :pagination, :period
           end
-          expect(subject.route_setting(:declared_params)).to eq [:page, :per_page, :start_date, :end_date]
+          expect(subject.route_setting(:declared_params)).to eq %i[page per_page start_date end_date]
         end
       end
 
@@ -1073,13 +1073,13 @@ def validate_param!(attr_name, params)
         before do
           subject.helpers do
             params :order do |options|
-              optional :order, type: Symbol, values: [:asc, :desc], default: options[:default_order]
+              optional :order, type: Symbol, values: %i[asc desc], default: options[:default_order]
               optional :order_by, type: Symbol, values: options[:order_by], default: options[:default_order_by]
             end
           end
           subject.format :json
           subject.params do
-            use :order, default_order: :asc, order_by: [:name, :created_at], default_order_by: :created_at
+            use :order, default_order: :asc, order_by: %i[name created_at], default_order_by: :created_at
           end
           subject.get '/order' do
             {
diff --git a/spec/support/content_type_helpers.rb b/spec/support/content_type_helpers.rb
index 1ec1851b3..5a23f0260 100644
--- a/spec/support/content_type_helpers.rb
+++ b/spec/support/content_type_helpers.rb
@@ -1,7 +1,7 @@
 module Spec
   module Support
     module Helpers
-      %w(put patch post delete).each do |method|
+      %w[put patch post delete].each do |method|
         define_method :"#{method}_with_json" do |uri, params = {}, env = {}, &block|
           params = params.to_json
           env['CONTENT_TYPE'] ||= 'application/json'