extracted boolean validation logic into stand-alone validator

app/models/code_ocean/file.rb

@@ -1,4 +1,5 @@
 require File.expand_path('../../../uploaders/file_uploader', __FILE__)
+require File.expand_path('../../../../lib/active_model/validations/boolean_presence_validator', __FILE__)
 
 module CodeOcean
   class File < ActiveRecord::Base
@@ -35,9 +36,9 @@ module CodeOcean
     validates :feedback_message, absence: true, unless: :teacher_defined_test?
     validates :file_type_id, presence: true
     validates :hashed_content, if: :content_present?, presence: true
-    validates :hidden, inclusion: {in: [true, false]}
+    validates :hidden, boolean_presence: true
     validates :name, presence: true
-    validates :read_only, inclusion: {in: [true, false]}
+    validates :read_only, boolean_presence: true
     validates :role, inclusion: {in: ROLES}
     validates :weight, if: :teacher_defined_test?, numericality: true, presence: true
     validates :weight, absence: true, unless: :teacher_defined_test?

app/models/execution_environment.rb

@@ -1,3 +1,5 @@
+require File.expand_path('../../../lib/active_model/validations/boolean_presence_validator', __FILE__)
+
 class ExecutionEnvironment < ActiveRecord::Base
   include Creation
   include DefaultValues
@@ -16,7 +18,7 @@ class ExecutionEnvironment < ActiveRecord::Base
   validate :working_docker_image?, if: :validate_docker_image?
   validates :docker_image, presence: true
   validates :memory_limit, numericality: {greater_than_or_equal_to: DockerClient::MINIMUM_MEMORY_LIMIT, only_integer: true}, presence: true
-  validates :network_enabled, inclusion: {in: [true, false]}
+  validates :network_enabled, boolean_presence: true
   validates :name, presence: true
   validates :permitted_execution_time, numericality: {only_integer: true}, presence: true
   validates :pool_size, numericality: {only_integer: true}, presence: true

app/models/exercise.rb

@@ -1,3 +1,5 @@
+require File.expand_path('../../../lib/active_model/validations/boolean_presence_validator', __FILE__)
+
 class Exercise < ActiveRecord::Base
   include Context
   include Creation
@@ -16,7 +18,7 @@ class Exercise < ActiveRecord::Base
   validate :valid_main_file?
   validates :description, presence: true
   validates :execution_environment_id, presence: true
-  validates :public, inclusion: {in: [true, false]}
+  validates :public, boolean_presence: true
   validates :title, presence: true
   validates :token, presence: true, uniqueness: true
 

app/models/file_type.rb

@@ -1,3 +1,5 @@
+require File.expand_path('../../../lib/active_model/validations/boolean_presence_validator', __FILE__)
+
 class FileType < ActiveRecord::Base
   include Creation
   include DefaultValues
@@ -11,12 +13,12 @@ class FileType < ActiveRecord::Base
   has_many :execution_environments
   has_many :files
 
-  validates :binary, inclusion: {in: [true, false]}
+  validates :binary, boolean_presence: true
   validates :editor_mode, presence: true, unless: :binary?
-  validates :executable, inclusion: {in: [true, false]}
+  validates :executable, boolean_presence: true
   validates :indent_size, presence: true, unless: :binary?
   validates :name, presence: true
-  validates :renderable, inclusion: {in: [true, false]}
+  validates :renderable, boolean_presence: true
 
   [:audio, :image, :video].each do |type|
     define_method("#{type}?") do