diff --git a/Gemfile b/Gemfile
index 0897dae..c5def96 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 source "https://rubygems.org"
 
 # Declare your gem's dependencies in diaspora_federation.gemspec.
diff --git a/Guardfile b/Guardfile
index ef40b68..d0f3e68 100644
--- a/Guardfile
+++ b/Guardfile
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 guard :rspec, cmd: "NO_COVERAGE=true bin/rspec" do
   require "guard/rspec/dsl"
   dsl = Guard::RSpec::Dsl.new(self)
diff --git a/Rakefile b/Rakefile
index ad80011..a3a1bb9 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 begin
   require "bundler/setup"
 rescue LoadError
diff --git a/app/controllers/diaspora_federation/application_controller.rb b/app/controllers/diaspora_federation/application_controller.rb
index 820394f..47eefd3 100644
--- a/app/controllers/diaspora_federation/application_controller.rb
+++ b/app/controllers/diaspora_federation/application_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   # Base controller for all DiasporaFederation controllers
   class ApplicationController < ActionController::Base
diff --git a/app/controllers/diaspora_federation/fetch_controller.rb b/app/controllers/diaspora_federation/fetch_controller.rb
index de5d651..24ec5fd 100644
--- a/app/controllers/diaspora_federation/fetch_controller.rb
+++ b/app/controllers/diaspora_federation/fetch_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_dependency "diaspora_federation/application_controller"
 
 module DiasporaFederation
diff --git a/app/controllers/diaspora_federation/h_card_controller.rb b/app/controllers/diaspora_federation/h_card_controller.rb
index b7d2f2e..b7af1f8 100644
--- a/app/controllers/diaspora_federation/h_card_controller.rb
+++ b/app/controllers/diaspora_federation/h_card_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_dependency "diaspora_federation/application_controller"
 
 module DiasporaFederation
diff --git a/app/controllers/diaspora_federation/receive_controller.rb b/app/controllers/diaspora_federation/receive_controller.rb
index 9155a8a..a477dfd 100644
--- a/app/controllers/diaspora_federation/receive_controller.rb
+++ b/app/controllers/diaspora_federation/receive_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_dependency "diaspora_federation/application_controller"
 
 module DiasporaFederation
diff --git a/app/controllers/diaspora_federation/webfinger_controller.rb b/app/controllers/diaspora_federation/webfinger_controller.rb
index 542eb8f..da275de 100644
--- a/app/controllers/diaspora_federation/webfinger_controller.rb
+++ b/app/controllers/diaspora_federation/webfinger_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_dependency "diaspora_federation/application_controller"
 
 module DiasporaFederation
diff --git a/config/initializers/filter_parameter_logging.rb b/config/initializers/filter_parameter_logging.rb
index 67516e1..4a8838c 100644
--- a/config/initializers/filter_parameter_logging.rb
+++ b/config/initializers/filter_parameter_logging.rb
@@ -1,2 +1,4 @@
+# frozen_string_literal: true
+
 # Don't log received xml data.
 Rails.application.config.filter_parameters += %i[xml aes_key encrypted_magic_envelope]
diff --git a/config/initializers/mime_types.rb b/config/initializers/mime_types.rb
index 10cadb2..27cecfb 100644
--- a/config/initializers/mime_types.rb
+++ b/config/initializers/mime_types.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # mime types for webfinger
 Mime::Type.register "application/jrd+json", :jrd
 Mime::Type.register "application/xrd+xml", :xrd
diff --git a/config/routes.rb b/config/routes.rb
index 30c1a98..2c34046 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 DiasporaFederation::Engine.routes.draw do
   controller :receive do
     post "receive/public"      => :public,  :as => "receive_public"
diff --git a/config/spring.rb b/config/spring.rb
index d8a7f92..2bf4187 100644
--- a/config/spring.rb
+++ b/config/spring.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 Spring.application_root = "./test/dummy"
 
 root_path = Pathname.new(File.expand_path("."))
diff --git a/diaspora_federation-json_schema.gemspec b/diaspora_federation-json_schema.gemspec
index d078a28..5cae269 100644
--- a/diaspora_federation-json_schema.gemspec
+++ b/diaspora_federation-json_schema.gemspec
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 $LOAD_PATH.push File.expand_path("lib", __dir__)
 
 # Maintain your gem's version:
diff --git a/diaspora_federation-rails.gemspec b/diaspora_federation-rails.gemspec
index df918a0..7148c82 100644
--- a/diaspora_federation-rails.gemspec
+++ b/diaspora_federation-rails.gemspec
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 $LOAD_PATH.push File.expand_path("lib", __dir__)
 
 # Maintain your gem's version:
diff --git a/diaspora_federation-test.gemspec b/diaspora_federation-test.gemspec
index 69df103..40a0da8 100644
--- a/diaspora_federation-test.gemspec
+++ b/diaspora_federation-test.gemspec
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 $LOAD_PATH.push File.expand_path("lib", __dir__)
 
 # Maintain your gem's version:
diff --git a/diaspora_federation.gemspec b/diaspora_federation.gemspec
index a2840e8..eaf83bc 100644
--- a/diaspora_federation.gemspec
+++ b/diaspora_federation.gemspec
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 $LOAD_PATH.push File.expand_path("lib", __dir__)
 
 # Maintain your gem's version:
diff --git a/lib/diaspora_federation.rb b/lib/diaspora_federation.rb
index 08c360a..6194da0 100644
--- a/lib/diaspora_federation.rb
+++ b/lib/diaspora_federation.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "nokogiri"
 require "openssl"
 
diff --git a/lib/diaspora_federation/callbacks.rb b/lib/diaspora_federation/callbacks.rb
index fae3689..c58fa34 100644
--- a/lib/diaspora_federation/callbacks.rb
+++ b/lib/diaspora_federation/callbacks.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   # Callbacks are used to communicate with the application. They are called to
   # fetch data and after data is received.
diff --git a/lib/diaspora_federation/discovery.rb b/lib/diaspora_federation/discovery.rb
index f4bd28d..ab587c9 100644
--- a/lib/diaspora_federation/discovery.rb
+++ b/lib/diaspora_federation/discovery.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   # This module provides the namespace for the various classes implementing
   # WebFinger and other protocols used for metadata discovery on remote servers
diff --git a/lib/diaspora_federation/discovery/discovery.rb b/lib/diaspora_federation/discovery/discovery.rb
index 5f24513..2c78970 100644
--- a/lib/diaspora_federation/discovery/discovery.rb
+++ b/lib/diaspora_federation/discovery/discovery.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Discovery
     # This class contains the logic to fetch all data for the given diaspora* ID.
@@ -49,13 +51,10 @@ module DiasporaFederation
         raise "Failed to fetch #{url}: #{response.status}" unless response.success?
         response.body
       rescue => e # rubocop:disable Style/RescueStandardError
-        unless http_fallback && url.start_with?("https://")
-          raise DiscoveryError, "Failed to fetch #{url} for #{diaspora_id}: #{e.class}: #{e.message}"
-        end
+        raise DiscoveryError, "Failed to fetch #{url} for #{diaspora_id}: #{e.class}: #{e.message}" unless http_fallback
 
         logger.warn "Retry with http: #{url} for #{diaspora_id}: #{e.class}: #{e.message}"
-        url.sub!("https://", "http://")
-        retry
+        get(url.sub("https://", "http://"))
       end
 
       def domain
diff --git a/lib/diaspora_federation/discovery/exceptions.rb b/lib/diaspora_federation/discovery/exceptions.rb
index caba207..3985b5b 100644
--- a/lib/diaspora_federation/discovery/exceptions.rb
+++ b/lib/diaspora_federation/discovery/exceptions.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Discovery
     # Raised, if there is an error while discover a new person
diff --git a/lib/diaspora_federation/discovery/h_card.rb b/lib/diaspora_federation/discovery/h_card.rb
index 69d7526..f486cde 100644
--- a/lib/diaspora_federation/discovery/h_card.rb
+++ b/lib/diaspora_federation/discovery/h_card.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Discovery
     # This class provides the means of generating and parsing account data to and
diff --git a/lib/diaspora_federation/discovery/host_meta.rb b/lib/diaspora_federation/discovery/host_meta.rb
index b7a8b95..cc15da0 100644
--- a/lib/diaspora_federation/discovery/host_meta.rb
+++ b/lib/diaspora_federation/discovery/host_meta.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Discovery
     # Generates and parses Host Meta documents.
@@ -25,7 +27,7 @@ module DiasporaFederation
       end
 
       # URL fragment to append to the base URL
-      WEBFINGER_SUFFIX = "/.well-known/webfinger.xml?resource={uri}".freeze
+      WEBFINGER_SUFFIX = "/.well-known/webfinger.xml?resource={uri}"
 
       # Returns the WebFinger URL that was used to build this instance (either from
       # xml or by giving a base URL).
diff --git a/lib/diaspora_federation/discovery/web_finger.rb b/lib/diaspora_federation/discovery/web_finger.rb
index 295038e..57c7033 100644
--- a/lib/diaspora_federation/discovery/web_finger.rb
+++ b/lib/diaspora_federation/discovery/web_finger.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Discovery
     # The WebFinger document used for diaspora* user discovery is based on an
@@ -69,23 +71,23 @@ module DiasporaFederation
       property :subscribe_url, :string, optional: true
 
       # +hcard_url+ link relation
-      REL_HCARD = "http://microformats.org/profile/hcard".freeze
+      REL_HCARD = "http://microformats.org/profile/hcard"
 
       # +seed_url+ link relation
-      REL_SEED = "http://joindiaspora.com/seed_location".freeze
+      REL_SEED = "http://joindiaspora.com/seed_location"
 
       # +profile_url+ link relation.
       # @note This might just as well be an +Alias+ instead of a +Link+.
-      REL_PROFILE = "http://webfinger.net/rel/profile-page".freeze
+      REL_PROFILE = "http://webfinger.net/rel/profile-page"
 
       # +atom_url+ link relation
-      REL_ATOM = "http://schemas.google.com/g/2010#updates-from".freeze
+      REL_ATOM = "http://schemas.google.com/g/2010#updates-from"
 
       # +salmon_url+ link relation
-      REL_SALMON = "salmon".freeze
+      REL_SALMON = "salmon"
 
       # +subscribe_url+ link relation
-      REL_SUBSCRIBE = "http://ostatus.org/schema/1.0/subscribe".freeze
+      REL_SUBSCRIBE = "http://ostatus.org/schema/1.0/subscribe"
 
       # Additional WebFinger data
       # @return [Hash] additional elements
diff --git a/lib/diaspora_federation/discovery/xrd_document.rb b/lib/diaspora_federation/discovery/xrd_document.rb
index 354594c..657dc74 100644
--- a/lib/diaspora_federation/discovery/xrd_document.rb
+++ b/lib/diaspora_federation/discovery/xrd_document.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Discovery
     # This class implements basic handling of XRD documents as far as it is
@@ -29,13 +31,13 @@ module DiasporaFederation
     # @see http://docs.oasis-open.org/xri/xrd/v1.0/xrd-1.0.html Extensible Resource Descriptor (XRD) Version 1.0
     class XrdDocument
       # xml namespace url
-      XMLNS = "http://docs.oasis-open.org/ns/xri/xrd-1.0".freeze
+      XMLNS = "http://docs.oasis-open.org/ns/xri/xrd-1.0"
 
       # +Link+ element attributes
       LINK_ATTRS = %i[rel type href template].freeze
 
       # format string for datetime (+Expires+ element)
-      DATETIME_FORMAT = "%Y-%m-%dT%H:%M:%SZ".freeze
+      DATETIME_FORMAT = "%Y-%m-%dT%H:%M:%SZ"
 
       # The <Expires> element contains a time value which specifies the instant at
       # and after which the document has expired and SHOULD NOT be used.
diff --git a/lib/diaspora_federation/engine.rb b/lib/diaspora_federation/engine.rb
index 0941467..3ab91df 100644
--- a/lib/diaspora_federation/engine.rb
+++ b/lib/diaspora_federation/engine.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   # diaspora* federation rails engine
   class Engine < ::Rails::Engine
diff --git a/lib/diaspora_federation/entities.rb b/lib/diaspora_federation/entities.rb
index a7689d0..d29388b 100644
--- a/lib/diaspora_federation/entities.rb
+++ b/lib/diaspora_federation/entities.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   # This namespace contains all the entities used to encapsulate data that is
   # passed around in the diaspora* network as part of the federation protocol.
diff --git a/lib/diaspora_federation/entities/account_deletion.rb b/lib/diaspora_federation/entities/account_deletion.rb
index 88e087e..d969b24 100644
--- a/lib/diaspora_federation/entities/account_deletion.rb
+++ b/lib/diaspora_federation/entities/account_deletion.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # This entity is sent when an account was deleted on a remote pod.
diff --git a/lib/diaspora_federation/entities/account_migration.rb b/lib/diaspora_federation/entities/account_migration.rb
index 2857a79..589d833 100644
--- a/lib/diaspora_federation/entities/account_migration.rb
+++ b/lib/diaspora_federation/entities/account_migration.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # This entity is sent when a person changes their diaspora* ID (e.g. when a user migration
diff --git a/lib/diaspora_federation/entities/account_migration/signable.rb b/lib/diaspora_federation/entities/account_migration/signable.rb
index 40cb5f1..fe8825d 100644
--- a/lib/diaspora_federation/entities/account_migration/signable.rb
+++ b/lib/diaspora_federation/entities/account_migration/signable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     class AccountMigration < Entity
diff --git a/lib/diaspora_federation/entities/comment.rb b/lib/diaspora_federation/entities/comment.rb
index b3f05e7..f271b1d 100644
--- a/lib/diaspora_federation/entities/comment.rb
+++ b/lib/diaspora_federation/entities/comment.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # This entity represents a comment to some kind of post (e.g. status message).
@@ -5,7 +7,7 @@ module DiasporaFederation
     # @see Validators::CommentValidator
     class Comment < Entity
       # The {Comment} parent is a {Post}
-      PARENT_TYPE = "Post".freeze
+      PARENT_TYPE = "Post"
 
       include Relayable
 
diff --git a/lib/diaspora_federation/entities/contact.rb b/lib/diaspora_federation/entities/contact.rb
index bd5c0f2..52e8d0e 100644
--- a/lib/diaspora_federation/entities/contact.rb
+++ b/lib/diaspora_federation/entities/contact.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # This entity represents a contact with another person. A user issues it
diff --git a/lib/diaspora_federation/entities/conversation.rb b/lib/diaspora_federation/entities/conversation.rb
index 57898d0..b3720d3 100644
--- a/lib/diaspora_federation/entities/conversation.rb
+++ b/lib/diaspora_federation/entities/conversation.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # This entity represents a private conversation between users.
diff --git a/lib/diaspora_federation/entities/embed.rb b/lib/diaspora_federation/entities/embed.rb
index 166b99a..76136f5 100644
--- a/lib/diaspora_federation/entities/embed.rb
+++ b/lib/diaspora_federation/entities/embed.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # This entity is used to specify embed information about an URL that should be embedded.
diff --git a/lib/diaspora_federation/entities/event.rb b/lib/diaspora_federation/entities/event.rb
index 274c1e3..02ddba7 100644
--- a/lib/diaspora_federation/entities/event.rb
+++ b/lib/diaspora_federation/entities/event.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # This entity represents an event and it is federated as a part of a status message.
diff --git a/lib/diaspora_federation/entities/event_participation.rb b/lib/diaspora_federation/entities/event_participation.rb
index 1dfa504..fd1eaac 100644
--- a/lib/diaspora_federation/entities/event_participation.rb
+++ b/lib/diaspora_federation/entities/event_participation.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # This entity represents a participation in an event, i.e. it is issued when a user responds to en event.
@@ -5,7 +7,7 @@ module DiasporaFederation
     # @see Validators::EventParticipationValidator
     class EventParticipation < Entity
       # The {EventParticipation} parent is an {Event}
-      PARENT_TYPE = "Event".freeze
+      PARENT_TYPE = "Event"
 
       include Relayable
 
diff --git a/lib/diaspora_federation/entities/like.rb b/lib/diaspora_federation/entities/like.rb
index b1b7b2e..b589058 100644
--- a/lib/diaspora_federation/entities/like.rb
+++ b/lib/diaspora_federation/entities/like.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # This entity represents a like to some kind of post (e.g. status message).
diff --git a/lib/diaspora_federation/entities/location.rb b/lib/diaspora_federation/entities/location.rb
index 5bd8501..3d0a134 100644
--- a/lib/diaspora_federation/entities/location.rb
+++ b/lib/diaspora_federation/entities/location.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # This entity is used to specify location data and used embedded in a status message.
diff --git a/lib/diaspora_federation/entities/message.rb b/lib/diaspora_federation/entities/message.rb
index c43b53b..81c631a 100644
--- a/lib/diaspora_federation/entities/message.rb
+++ b/lib/diaspora_federation/entities/message.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # This entity represents a private message exchanged in private conversation.
diff --git a/lib/diaspora_federation/entities/participation.rb b/lib/diaspora_federation/entities/participation.rb
index 25f9aa5..554d9bd 100644
--- a/lib/diaspora_federation/entities/participation.rb
+++ b/lib/diaspora_federation/entities/participation.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # Participation is sent to subscribe a user on updates for some post.
diff --git a/lib/diaspora_federation/entities/person.rb b/lib/diaspora_federation/entities/person.rb
index ab48857..e4ad225 100644
--- a/lib/diaspora_federation/entities/person.rb
+++ b/lib/diaspora_federation/entities/person.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # This entity contains the base data of a person.
diff --git a/lib/diaspora_federation/entities/photo.rb b/lib/diaspora_federation/entities/photo.rb
index 0e60f31..4f11179 100644
--- a/lib/diaspora_federation/entities/photo.rb
+++ b/lib/diaspora_federation/entities/photo.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # This entity represents a photo and it is federated as a part of a status message.
diff --git a/lib/diaspora_federation/entities/poll.rb b/lib/diaspora_federation/entities/poll.rb
index 47fd2dc..6f3ba16 100644
--- a/lib/diaspora_federation/entities/poll.rb
+++ b/lib/diaspora_federation/entities/poll.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # This entity represents a poll and it is federated as an optional part of a status message.
diff --git a/lib/diaspora_federation/entities/poll_answer.rb b/lib/diaspora_federation/entities/poll_answer.rb
index 7c1ee17..2eb34dc 100644
--- a/lib/diaspora_federation/entities/poll_answer.rb
+++ b/lib/diaspora_federation/entities/poll_answer.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # This entity represents a poll answer and is federated as a part of the Poll entity.
diff --git a/lib/diaspora_federation/entities/poll_participation.rb b/lib/diaspora_federation/entities/poll_participation.rb
index d1ce464..ec7eb86 100644
--- a/lib/diaspora_federation/entities/poll_participation.rb
+++ b/lib/diaspora_federation/entities/poll_participation.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # This entity represents a participation in poll, i.e. it is issued when a user votes for an answer in a poll.
@@ -5,7 +7,7 @@ module DiasporaFederation
     # @see Validators::PollParticipationValidator
     class PollParticipation < Entity
       # The {PollParticipation} parent is a {Poll}
-      PARENT_TYPE = "Poll".freeze
+      PARENT_TYPE = "Poll"
 
       include Relayable
 
diff --git a/lib/diaspora_federation/entities/post.rb b/lib/diaspora_federation/entities/post.rb
index 6957cdf..a5c0a48 100644
--- a/lib/diaspora_federation/entities/post.rb
+++ b/lib/diaspora_federation/entities/post.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # This is a module that defines common properties for a post which
diff --git a/lib/diaspora_federation/entities/profile.rb b/lib/diaspora_federation/entities/profile.rb
index ea851b1..b6ba0ff 100644
--- a/lib/diaspora_federation/entities/profile.rb
+++ b/lib/diaspora_federation/entities/profile.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # This entity contains all the profile data of a person.
diff --git a/lib/diaspora_federation/entities/related_entity.rb b/lib/diaspora_federation/entities/related_entity.rb
index b384748..ac90d01 100644
--- a/lib/diaspora_federation/entities/related_entity.rb
+++ b/lib/diaspora_federation/entities/related_entity.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # Entity meta informations for a related entity (parent or target of
diff --git a/lib/diaspora_federation/entities/relayable.rb b/lib/diaspora_federation/entities/relayable.rb
index 4ee3ffa..a0ebc11 100644
--- a/lib/diaspora_federation/entities/relayable.rb
+++ b/lib/diaspora_federation/entities/relayable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # This is a module that defines common properties for relayable entities
diff --git a/lib/diaspora_federation/entities/relayable_retraction.rb b/lib/diaspora_federation/entities/relayable_retraction.rb
index aa7b03f..d0365f1 100644
--- a/lib/diaspora_federation/entities/relayable_retraction.rb
+++ b/lib/diaspora_federation/entities/relayable_retraction.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # This entity represents a claim of deletion of a previously federated
diff --git a/lib/diaspora_federation/entities/request.rb b/lib/diaspora_federation/entities/request.rb
index a60aab1..6627f36 100644
--- a/lib/diaspora_federation/entities/request.rb
+++ b/lib/diaspora_federation/entities/request.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # This entity represents a sharing request for a user. A user issues it
diff --git a/lib/diaspora_federation/entities/reshare.rb b/lib/diaspora_federation/entities/reshare.rb
index 7c0bcc6..aa38b29 100644
--- a/lib/diaspora_federation/entities/reshare.rb
+++ b/lib/diaspora_federation/entities/reshare.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # This entity represents the fact that a user reshared another user's post.
diff --git a/lib/diaspora_federation/entities/retraction.rb b/lib/diaspora_federation/entities/retraction.rb
index 217c0a6..83f6e93 100644
--- a/lib/diaspora_federation/entities/retraction.rb
+++ b/lib/diaspora_federation/entities/retraction.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # This entity represents a claim of deletion of a previously federated entity.
diff --git a/lib/diaspora_federation/entities/signable.rb b/lib/diaspora_federation/entities/signable.rb
index d78d4a5..1301f17 100644
--- a/lib/diaspora_federation/entities/signable.rb
+++ b/lib/diaspora_federation/entities/signable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # Signable is a module that encapsulates basic signature generation/verification flow for entities.
diff --git a/lib/diaspora_federation/entities/signed_retraction.rb b/lib/diaspora_federation/entities/signed_retraction.rb
index af850b9..77e474c 100644
--- a/lib/diaspora_federation/entities/signed_retraction.rb
+++ b/lib/diaspora_federation/entities/signed_retraction.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # This entity represents a claim of deletion of a previously federated
diff --git a/lib/diaspora_federation/entities/status_message.rb b/lib/diaspora_federation/entities/status_message.rb
index 6a50b61..1da0d8b 100644
--- a/lib/diaspora_federation/entities/status_message.rb
+++ b/lib/diaspora_federation/entities/status_message.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     # This entity represents a status message sent by a user.
diff --git a/lib/diaspora_federation/entity.rb b/lib/diaspora_federation/entity.rb
index 7b564be..3f81ad6 100644
--- a/lib/diaspora_federation/entity.rb
+++ b/lib/diaspora_federation/entity.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   # +Entity+ is the base class for all other objects used to encapsulate data
   # for federation messages in the diaspora* network.
@@ -41,7 +43,7 @@ module DiasporaFederation
     INVALID_XML_REGEX = /[^\x09\x0A\x0D\x20-\uD7FF\uE000-\uFFFD\u{10000}-\u{10FFFF}]/
 
     # Regex to validate and find entity names
-    ENTITY_NAME_REGEX = "[a-z]*(?:_[a-z]*)*".freeze
+    ENTITY_NAME_REGEX = "[a-z]*(?:_[a-z]*)*"
 
     # Initializes the Entity with the given attribute hash and freezes the created
     # instance it returns.
diff --git a/lib/diaspora_federation/federation.rb b/lib/diaspora_federation/federation.rb
index b279cfd..e1ccd95 100644
--- a/lib/diaspora_federation/federation.rb
+++ b/lib/diaspora_federation/federation.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   # This module contains the federation logic
   module Federation
diff --git a/lib/diaspora_federation/federation/diaspora_url_parser.rb b/lib/diaspora_federation/federation/diaspora_url_parser.rb
index 5b59da2..cfb1f00 100644
--- a/lib/diaspora_federation/federation/diaspora_url_parser.rb
+++ b/lib/diaspora_federation/federation/diaspora_url_parser.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Federation
     # This module is for parsing and fetching linked entities.
diff --git a/lib/diaspora_federation/federation/fetcher.rb b/lib/diaspora_federation/federation/fetcher.rb
index d9b85cf..b249903 100644
--- a/lib/diaspora_federation/federation/fetcher.rb
+++ b/lib/diaspora_federation/federation/fetcher.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Federation
     # This module is for fetching entities from other pods.
diff --git a/lib/diaspora_federation/federation/receiver.rb b/lib/diaspora_federation/federation/receiver.rb
index 76903e5..f5b50da 100644
--- a/lib/diaspora_federation/federation/receiver.rb
+++ b/lib/diaspora_federation/federation/receiver.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Federation
     # This module parses and receives entities.
diff --git a/lib/diaspora_federation/federation/receiver/abstract_receiver.rb b/lib/diaspora_federation/federation/receiver/abstract_receiver.rb
index c244c1d..74b8abd 100644
--- a/lib/diaspora_federation/federation/receiver/abstract_receiver.rb
+++ b/lib/diaspora_federation/federation/receiver/abstract_receiver.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Federation
     module Receiver
diff --git a/lib/diaspora_federation/federation/receiver/exceptions.rb b/lib/diaspora_federation/federation/receiver/exceptions.rb
index 5c1a0b8..a48a20e 100644
--- a/lib/diaspora_federation/federation/receiver/exceptions.rb
+++ b/lib/diaspora_federation/federation/receiver/exceptions.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Federation
     module Receiver
diff --git a/lib/diaspora_federation/federation/receiver/private.rb b/lib/diaspora_federation/federation/receiver/private.rb
index 18115cf..2e45a3f 100644
--- a/lib/diaspora_federation/federation/receiver/private.rb
+++ b/lib/diaspora_federation/federation/receiver/private.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Federation
     module Receiver
diff --git a/lib/diaspora_federation/federation/receiver/public.rb b/lib/diaspora_federation/federation/receiver/public.rb
index 7711088..d56611d 100644
--- a/lib/diaspora_federation/federation/receiver/public.rb
+++ b/lib/diaspora_federation/federation/receiver/public.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Federation
     module Receiver
diff --git a/lib/diaspora_federation/federation/sender.rb b/lib/diaspora_federation/federation/sender.rb
index ab15662..37f7a72 100644
--- a/lib/diaspora_federation/federation/sender.rb
+++ b/lib/diaspora_federation/federation/sender.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Federation
     # Federation logic to send messages to other pods
diff --git a/lib/diaspora_federation/federation/sender/hydra_wrapper.rb b/lib/diaspora_federation/federation/sender/hydra_wrapper.rb
index b300b07..df1adf1 100644
--- a/lib/diaspora_federation/federation/sender/hydra_wrapper.rb
+++ b/lib/diaspora_federation/federation/sender/hydra_wrapper.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "typhoeus"
 
 module DiasporaFederation
diff --git a/lib/diaspora_federation/http_client.rb b/lib/diaspora_federation/http_client.rb
index 8cf0fa1..df536a0 100644
--- a/lib/diaspora_federation/http_client.rb
+++ b/lib/diaspora_federation/http_client.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "faraday"
 require "faraday_middleware/response/follow_redirects"
 
diff --git a/lib/diaspora_federation/logging.rb b/lib/diaspora_federation/logging.rb
index 4593c28..29fb7b2 100644
--- a/lib/diaspora_federation/logging.rb
+++ b/lib/diaspora_federation/logging.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   # Logging module for the diaspora* federation
   #
diff --git a/lib/diaspora_federation/parsers.rb b/lib/diaspora_federation/parsers.rb
index a08ba5c..783ab8e 100644
--- a/lib/diaspora_federation/parsers.rb
+++ b/lib/diaspora_federation/parsers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   # This namespace contains parsers which are used to deserialize federation entities
   # objects from supported formats (XML, JSON) to objects of DiasporaFederation::Entity
diff --git a/lib/diaspora_federation/parsers/base_parser.rb b/lib/diaspora_federation/parsers/base_parser.rb
index 50b48b9..8727dba 100644
--- a/lib/diaspora_federation/parsers/base_parser.rb
+++ b/lib/diaspora_federation/parsers/base_parser.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Parsers
     # +BaseParser+ is an abstract class which is used for defining parsers for different
diff --git a/lib/diaspora_federation/parsers/json_parser.rb b/lib/diaspora_federation/parsers/json_parser.rb
index ff7c0aa..3d7adcd 100644
--- a/lib/diaspora_federation/parsers/json_parser.rb
+++ b/lib/diaspora_federation/parsers/json_parser.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Parsers
     # This is a parser of JSON serialized object. JSON object format is defined by
diff --git a/lib/diaspora_federation/parsers/relayable_json_parser.rb b/lib/diaspora_federation/parsers/relayable_json_parser.rb
index 192a572..61d5f00 100644
--- a/lib/diaspora_federation/parsers/relayable_json_parser.rb
+++ b/lib/diaspora_federation/parsers/relayable_json_parser.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Parsers
     # This is a parser of JSON serialized object, that is normally used for parsing data of relayables.
diff --git a/lib/diaspora_federation/parsers/relayable_xml_parser.rb b/lib/diaspora_federation/parsers/relayable_xml_parser.rb
index 272a4ca..4372854 100644
--- a/lib/diaspora_federation/parsers/relayable_xml_parser.rb
+++ b/lib/diaspora_federation/parsers/relayable_xml_parser.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Parsers
     # This is a parser of XML serialized object that is normally used for parsing data of relayables.
diff --git a/lib/diaspora_federation/parsers/xml_parser.rb b/lib/diaspora_federation/parsers/xml_parser.rb
index 2e04418..07f2f47 100644
--- a/lib/diaspora_federation/parsers/xml_parser.rb
+++ b/lib/diaspora_federation/parsers/xml_parser.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Parsers
     # This is a parser of XML serialized object.
diff --git a/lib/diaspora_federation/properties_dsl.rb b/lib/diaspora_federation/properties_dsl.rb
index 2b4cef8..04fbaa4 100644
--- a/lib/diaspora_federation/properties_dsl.rb
+++ b/lib/diaspora_federation/properties_dsl.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   # Provides a simple DSL for specifying {Entity} properties during class
   # definition.
diff --git a/lib/diaspora_federation/rails.rb b/lib/diaspora_federation/rails.rb
index dd551a7..cd2577a 100644
--- a/lib/diaspora_federation/rails.rb
+++ b/lib/diaspora_federation/rails.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "diaspora_federation/engine"
 
 require "diaspora_federation"
diff --git a/lib/diaspora_federation/salmon.rb b/lib/diaspora_federation/salmon.rb
index 79c0216..0fc3ef9 100644
--- a/lib/diaspora_federation/salmon.rb
+++ b/lib/diaspora_federation/salmon.rb
@@ -1,9 +1,11 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   # This module contains a diaspora*-specific implementation of parts of the
   # {http://www.salmon-protocol.org/ Salmon Protocol}.
   module Salmon
     # XML namespace url
-    XMLNS = "https://joindiaspora.com/protocol".freeze
+    XMLNS = "https://joindiaspora.com/protocol"
   end
 end
 
diff --git a/lib/diaspora_federation/salmon/aes.rb b/lib/diaspora_federation/salmon/aes.rb
index 9a717c3..cc55e28 100644
--- a/lib/diaspora_federation/salmon/aes.rb
+++ b/lib/diaspora_federation/salmon/aes.rb
@@ -1,9 +1,11 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Salmon
     # Class for AES encryption and decryption
     class AES
       # OpenSSL aes cipher definition
-      CIPHER = "AES-256-CBC".freeze
+      CIPHER = "AES-256-CBC"
 
       # Generates a random AES key and initialization vector
       # @return [Hash] { key: "...", iv: "..." }
diff --git a/lib/diaspora_federation/salmon/encrypted_magic_envelope.rb b/lib/diaspora_federation/salmon/encrypted_magic_envelope.rb
index a883474..83b585d 100644
--- a/lib/diaspora_federation/salmon/encrypted_magic_envelope.rb
+++ b/lib/diaspora_federation/salmon/encrypted_magic_envelope.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Salmon
     # This is a simple crypt-wrapper for {MagicEnvelope}.
diff --git a/lib/diaspora_federation/salmon/encrypted_slap.rb b/lib/diaspora_federation/salmon/encrypted_slap.rb
index 2fa772f..29f8a13 100644
--- a/lib/diaspora_federation/salmon/encrypted_slap.rb
+++ b/lib/diaspora_federation/salmon/encrypted_slap.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "json"
 
 module DiasporaFederation
diff --git a/lib/diaspora_federation/salmon/exceptions.rb b/lib/diaspora_federation/salmon/exceptions.rb
index 9dd0f96..07061be 100644
--- a/lib/diaspora_federation/salmon/exceptions.rb
+++ b/lib/diaspora_federation/salmon/exceptions.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Salmon
     # Raised, if the element containing the Magic Envelope is missing from the XML
diff --git a/lib/diaspora_federation/salmon/magic_envelope.rb b/lib/diaspora_federation/salmon/magic_envelope.rb
index ac53e95..07a3a37 100644
--- a/lib/diaspora_federation/salmon/magic_envelope.rb
+++ b/lib/diaspora_federation/salmon/magic_envelope.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Salmon
     # Represents a Magic Envelope for diaspora* federation messages
@@ -24,19 +26,19 @@ module DiasporaFederation
       include Logging
 
       # Encoding used for the payload data
-      ENCODING = "base64url".freeze
+      ENCODING = "base64url"
 
       # Algorithm used for signing the payload data
-      ALGORITHM = "RSA-SHA256".freeze
+      ALGORITHM = "RSA-SHA256"
 
       # Mime type describing the payload data
-      DATA_TYPE = "application/xml".freeze
+      DATA_TYPE = "application/xml"
 
       # Digest instance used for signing
       DIGEST = OpenSSL::Digest::SHA256.new
 
       # XML namespace url
-      XMLNS = "http://salmon-protocol.org/ns/magic-env".freeze
+      XMLNS = "http://salmon-protocol.org/ns/magic-env"
 
       # The payload entity of the magic envelope
       # @return [Entity] payload entity
diff --git a/lib/diaspora_federation/salmon/slap.rb b/lib/diaspora_federation/salmon/slap.rb
index f0daa92..cca7226 100644
--- a/lib/diaspora_federation/salmon/slap.rb
+++ b/lib/diaspora_federation/salmon/slap.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Salmon
     # +Slap+ provides class methods to create unencrypted Slap XML from payload
diff --git a/lib/diaspora_federation/salmon/xml_payload.rb b/lib/diaspora_federation/salmon/xml_payload.rb
index 90d8557..32ea453 100644
--- a/lib/diaspora_federation/salmon/xml_payload.rb
+++ b/lib/diaspora_federation/salmon/xml_payload.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Salmon
     # +XmlPayload+ provides methods to wrap a XML-serialized {Entity} inside a
diff --git a/lib/diaspora_federation/schemas.rb b/lib/diaspora_federation/schemas.rb
index 5b7120a..d04de47 100644
--- a/lib/diaspora_federation/schemas.rb
+++ b/lib/diaspora_federation/schemas.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "pathname"
 require "json"
 
@@ -5,7 +7,7 @@ module DiasporaFederation
   # A helper class to access the JSON schema.
   module Schemas
     # federation_entities schema uri
-    FEDERATION_ENTITIES_URI = "https://diaspora.github.io/diaspora_federation/schemas/federation_entities.json".freeze
+    FEDERATION_ENTITIES_URI = "https://diaspora.github.io/diaspora_federation/schemas/federation_entities.json"
 
     # Parsed federation_entities schema
     def self.federation_entities
diff --git a/lib/diaspora_federation/test.rb b/lib/diaspora_federation/test.rb
index db81377..60e136f 100644
--- a/lib/diaspora_federation/test.rb
+++ b/lib/diaspora_federation/test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "fabrication"
 
 require "diaspora_federation"
diff --git a/lib/diaspora_federation/test/entity_generator.rb b/lib/diaspora_federation/test/entity_generator.rb
index 1f9c7e6..9e610c0 100644
--- a/lib/diaspora_federation/test/entity_generator.rb
+++ b/lib/diaspora_federation/test/entity_generator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Test
     # Generator to instantiate entities
diff --git a/lib/diaspora_federation/test/factories.rb b/lib/diaspora_federation/test/factories.rb
index 38e8d99..92dd1c0 100644
--- a/lib/diaspora_federation/test/factories.rb
+++ b/lib/diaspora_federation/test/factories.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "uuid"
 require "securerandom"
 require "diaspora_federation/test"
diff --git a/lib/diaspora_federation/validators.rb b/lib/diaspora_federation/validators.rb
index 986daef..4ab6a70 100644
--- a/lib/diaspora_federation/validators.rb
+++ b/lib/diaspora_federation/validators.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "validation"
 require "validation/rule/regular_expression"
 require "validation/rule/length"
diff --git a/lib/diaspora_federation/validators/account_deletion_validator.rb b/lib/diaspora_federation/validators/account_deletion_validator.rb
index 60a32cf..f297e37 100644
--- a/lib/diaspora_federation/validators/account_deletion_validator.rb
+++ b/lib/diaspora_federation/validators/account_deletion_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # This validates a {Entities::AccountDeletion}.
diff --git a/lib/diaspora_federation/validators/account_migration_validator.rb b/lib/diaspora_federation/validators/account_migration_validator.rb
index 36c38be..206a2ff 100644
--- a/lib/diaspora_federation/validators/account_migration_validator.rb
+++ b/lib/diaspora_federation/validators/account_migration_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # This validates a {Entities::AccountMigration}.
diff --git a/lib/diaspora_federation/validators/comment_validator.rb b/lib/diaspora_federation/validators/comment_validator.rb
index 4669f50..3f4ac65 100644
--- a/lib/diaspora_federation/validators/comment_validator.rb
+++ b/lib/diaspora_federation/validators/comment_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # This validates a {Entities::Comment}.
diff --git a/lib/diaspora_federation/validators/contact_validator.rb b/lib/diaspora_federation/validators/contact_validator.rb
index cf313cc..d8f4f2c 100644
--- a/lib/diaspora_federation/validators/contact_validator.rb
+++ b/lib/diaspora_federation/validators/contact_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # This validates a {Entities::Contact}.
diff --git a/lib/diaspora_federation/validators/conversation_validator.rb b/lib/diaspora_federation/validators/conversation_validator.rb
index 1e66994..da984c6 100644
--- a/lib/diaspora_federation/validators/conversation_validator.rb
+++ b/lib/diaspora_federation/validators/conversation_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # This validates a {Entities::Conversation}.
diff --git a/lib/diaspora_federation/validators/embed_validator.rb b/lib/diaspora_federation/validators/embed_validator.rb
index de766cc..6486035 100644
--- a/lib/diaspora_federation/validators/embed_validator.rb
+++ b/lib/diaspora_federation/validators/embed_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # This validates a {Entities::Embed}.
diff --git a/lib/diaspora_federation/validators/event_participation_validator.rb b/lib/diaspora_federation/validators/event_participation_validator.rb
index 8e1209f..cfa6f61 100644
--- a/lib/diaspora_federation/validators/event_participation_validator.rb
+++ b/lib/diaspora_federation/validators/event_participation_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # This validates a {Entities::EventParticipation}.
diff --git a/lib/diaspora_federation/validators/event_validator.rb b/lib/diaspora_federation/validators/event_validator.rb
index a6c0aa6..ce37dbe 100644
--- a/lib/diaspora_federation/validators/event_validator.rb
+++ b/lib/diaspora_federation/validators/event_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # This validates a {Entities::Event}.
diff --git a/lib/diaspora_federation/validators/h_card_validator.rb b/lib/diaspora_federation/validators/h_card_validator.rb
index 236d88e..6612e1b 100644
--- a/lib/diaspora_federation/validators/h_card_validator.rb
+++ b/lib/diaspora_federation/validators/h_card_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # This validates a {Discovery::HCard}.
diff --git a/lib/diaspora_federation/validators/like_validator.rb b/lib/diaspora_federation/validators/like_validator.rb
index 60bb64c..97490b3 100644
--- a/lib/diaspora_federation/validators/like_validator.rb
+++ b/lib/diaspora_federation/validators/like_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # This validates a {Entities::Like}.
diff --git a/lib/diaspora_federation/validators/location_validator.rb b/lib/diaspora_federation/validators/location_validator.rb
index cd6e952..656f82e 100644
--- a/lib/diaspora_federation/validators/location_validator.rb
+++ b/lib/diaspora_federation/validators/location_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # This validates a {Entities::Location}.
diff --git a/lib/diaspora_federation/validators/message_validator.rb b/lib/diaspora_federation/validators/message_validator.rb
index 6ded966..9064a06 100644
--- a/lib/diaspora_federation/validators/message_validator.rb
+++ b/lib/diaspora_federation/validators/message_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # This validates a {Entities::Message}.
diff --git a/lib/diaspora_federation/validators/optional_aware_validator.rb b/lib/diaspora_federation/validators/optional_aware_validator.rb
index 1c0b467..178f17b 100644
--- a/lib/diaspora_federation/validators/optional_aware_validator.rb
+++ b/lib/diaspora_federation/validators/optional_aware_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # Abstract validator which only validates optional fields when they are not nil.
diff --git a/lib/diaspora_federation/validators/participation_validator.rb b/lib/diaspora_federation/validators/participation_validator.rb
index c3c4917..315887b 100644
--- a/lib/diaspora_federation/validators/participation_validator.rb
+++ b/lib/diaspora_federation/validators/participation_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # This validates a {Entities::Participation}.
diff --git a/lib/diaspora_federation/validators/person_validator.rb b/lib/diaspora_federation/validators/person_validator.rb
index ddfad99..147da56 100644
--- a/lib/diaspora_federation/validators/person_validator.rb
+++ b/lib/diaspora_federation/validators/person_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # This validates a {Entities::Person}.
diff --git a/lib/diaspora_federation/validators/photo_validator.rb b/lib/diaspora_federation/validators/photo_validator.rb
index 7c18107..02af975 100644
--- a/lib/diaspora_federation/validators/photo_validator.rb
+++ b/lib/diaspora_federation/validators/photo_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # This validates a {Entities::Photo}.
diff --git a/lib/diaspora_federation/validators/poll_answer_validator.rb b/lib/diaspora_federation/validators/poll_answer_validator.rb
index 4c55f05..b22668b 100644
--- a/lib/diaspora_federation/validators/poll_answer_validator.rb
+++ b/lib/diaspora_federation/validators/poll_answer_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # This validates a {Entities::PollAnswer}.
diff --git a/lib/diaspora_federation/validators/poll_participation_validator.rb b/lib/diaspora_federation/validators/poll_participation_validator.rb
index 65cb7db..8410c22 100644
--- a/lib/diaspora_federation/validators/poll_participation_validator.rb
+++ b/lib/diaspora_federation/validators/poll_participation_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # This validates a {Entities::PollParticipation}.
diff --git a/lib/diaspora_federation/validators/poll_validator.rb b/lib/diaspora_federation/validators/poll_validator.rb
index 103b85f..1a8a49e 100644
--- a/lib/diaspora_federation/validators/poll_validator.rb
+++ b/lib/diaspora_federation/validators/poll_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # This validates a {Entities::Poll}.
diff --git a/lib/diaspora_federation/validators/profile_validator.rb b/lib/diaspora_federation/validators/profile_validator.rb
index 38ef3e3..cea39be 100644
--- a/lib/diaspora_federation/validators/profile_validator.rb
+++ b/lib/diaspora_federation/validators/profile_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # This validates a {Entities::Profile}.
diff --git a/lib/diaspora_federation/validators/related_entity_validator.rb b/lib/diaspora_federation/validators/related_entity_validator.rb
index 17c2726..0c6e99f 100644
--- a/lib/diaspora_federation/validators/related_entity_validator.rb
+++ b/lib/diaspora_federation/validators/related_entity_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # This validates a {Entities::RelatedEntity}.
diff --git a/lib/diaspora_federation/validators/relayable_validator.rb b/lib/diaspora_federation/validators/relayable_validator.rb
index 618f3ce..11f155f 100644
--- a/lib/diaspora_federation/validators/relayable_validator.rb
+++ b/lib/diaspora_federation/validators/relayable_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # This is included to validatros which validate entities which include {Entities::Relayable}.
diff --git a/lib/diaspora_federation/validators/reshare_validator.rb b/lib/diaspora_federation/validators/reshare_validator.rb
index 343e36b..46de5e6 100644
--- a/lib/diaspora_federation/validators/reshare_validator.rb
+++ b/lib/diaspora_federation/validators/reshare_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # This validates a {Entities::Reshare}.
diff --git a/lib/diaspora_federation/validators/retraction_validator.rb b/lib/diaspora_federation/validators/retraction_validator.rb
index 922b44f..6400ae0 100644
--- a/lib/diaspora_federation/validators/retraction_validator.rb
+++ b/lib/diaspora_federation/validators/retraction_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # This validates a {Entities::Retraction}.
diff --git a/lib/diaspora_federation/validators/rules/birthday.rb b/lib/diaspora_federation/validators/rules/birthday.rb
index 0630ad1..21c28a0 100644
--- a/lib/diaspora_federation/validators/rules/birthday.rb
+++ b/lib/diaspora_federation/validators/rules/birthday.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "date"
 
 module Validation
diff --git a/lib/diaspora_federation/validators/rules/boolean.rb b/lib/diaspora_federation/validators/rules/boolean.rb
index 6c0418d..01f0e30 100644
--- a/lib/diaspora_federation/validators/rules/boolean.rb
+++ b/lib/diaspora_federation/validators/rules/boolean.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Validation
   module Rule
     # Boolean validation rule
diff --git a/lib/diaspora_federation/validators/rules/diaspora_id.rb b/lib/diaspora_federation/validators/rules/diaspora_id.rb
index 42bcc0b..15b0035 100644
--- a/lib/diaspora_federation/validators/rules/diaspora_id.rb
+++ b/lib/diaspora_federation/validators/rules/diaspora_id.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Validation
   module Rule
     # diaspora* ID validation rule
diff --git a/lib/diaspora_federation/validators/rules/diaspora_id_list.rb b/lib/diaspora_federation/validators/rules/diaspora_id_list.rb
index 85e1937..2c4837c 100644
--- a/lib/diaspora_federation/validators/rules/diaspora_id_list.rb
+++ b/lib/diaspora_federation/validators/rules/diaspora_id_list.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Validation
   module Rule
     # Rule for validating the number of diaspora* IDs in a string.
diff --git a/lib/diaspora_federation/validators/rules/guid.rb b/lib/diaspora_federation/validators/rules/guid.rb
index 3e30874..23f1748 100644
--- a/lib/diaspora_federation/validators/rules/guid.rb
+++ b/lib/diaspora_federation/validators/rules/guid.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Validation
   module Rule
     # GUID validation rule
@@ -9,7 +11,7 @@ module Validation
     # Special chars aren't allowed at the end.
     class Guid
       # Allowed chars to validate a GUID with a regex
-      VALID_CHARS = "[0-9A-Za-z\\-_@.:]{15,254}[0-9A-Za-z]".freeze
+      VALID_CHARS = "[0-9A-Za-z\\-_@.:]{15,254}[0-9A-Za-z]"
 
       # The error key for this rule
       # @return [Symbol] error key
diff --git a/lib/diaspora_federation/validators/rules/not_nil.rb b/lib/diaspora_federation/validators/rules/not_nil.rb
index 3fb6950..ce3b2c0 100644
--- a/lib/diaspora_federation/validators/rules/not_nil.rb
+++ b/lib/diaspora_federation/validators/rules/not_nil.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Validation
   module Rule
     # Validates that a property is not +nil+
diff --git a/lib/diaspora_federation/validators/rules/public_key.rb b/lib/diaspora_federation/validators/rules/public_key.rb
index 7b94802..77a2227 100644
--- a/lib/diaspora_federation/validators/rules/public_key.rb
+++ b/lib/diaspora_federation/validators/rules/public_key.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Validation
   module Rule
     # Public key validation rule
diff --git a/lib/diaspora_federation/validators/rules/tag_count.rb b/lib/diaspora_federation/validators/rules/tag_count.rb
index 4033605..ccf249a 100644
--- a/lib/diaspora_federation/validators/rules/tag_count.rb
+++ b/lib/diaspora_federation/validators/rules/tag_count.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Validation
   module Rule
     # Rule for validating the number of tags in a string.
diff --git a/lib/diaspora_federation/validators/status_message_validator.rb b/lib/diaspora_federation/validators/status_message_validator.rb
index 62eee98..6b70b55 100644
--- a/lib/diaspora_federation/validators/status_message_validator.rb
+++ b/lib/diaspora_federation/validators/status_message_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # This validates a {Entities::StatusMessage}.
diff --git a/lib/diaspora_federation/validators/web_finger_validator.rb b/lib/diaspora_federation/validators/web_finger_validator.rb
index 596f14c..8769750 100644
--- a/lib/diaspora_federation/validators/web_finger_validator.rb
+++ b/lib/diaspora_federation/validators/web_finger_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Validators
     # This validates a {Discovery::WebFinger}.
diff --git a/lib/diaspora_federation/version.rb b/lib/diaspora_federation/version.rb
index 1255d74..7f64d6c 100644
--- a/lib/diaspora_federation/version.rb
+++ b/lib/diaspora_federation/version.rb
@@ -1,4 +1,6 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   # the gem version
-  VERSION = "0.2.6".freeze
+  VERSION = "0.2.6"
 end
diff --git a/lib/tasks/build.rake b/lib/tasks/build.rake
index ef74168..945f47b 100644
--- a/lib/tasks/build.rake
+++ b/lib/tasks/build.rake
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 desc "Build gem into the pkg directory"
 task build: :test do
   FileUtils.rm_rf("pkg")
diff --git a/lib/tasks/gemfiles.rake b/lib/tasks/gemfiles.rake
index 52d3fa2..3500bdd 100644
--- a/lib/tasks/gemfiles.rake
+++ b/lib/tasks/gemfiles.rake
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 namespace :gemfiles do
   desc "Generates no-rails.Gemfile"
   task :generate do
diff --git a/spec/controllers/diaspora_federation/application_controller_spec.rb b/spec/controllers/diaspora_federation/application_controller_spec.rb
index 79084c4..70bf828 100644
--- a/spec/controllers/diaspora_federation/application_controller_spec.rb
+++ b/spec/controllers/diaspora_federation/application_controller_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe ApplicationController, type: :controller do
     controller do
diff --git a/spec/controllers/diaspora_federation/fetch_controller_spec.rb b/spec/controllers/diaspora_federation/fetch_controller_spec.rb
index 22916e9..ec80207 100644
--- a/spec/controllers/diaspora_federation/fetch_controller_spec.rb
+++ b/spec/controllers/diaspora_federation/fetch_controller_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe FetchController, type: :controller do
     routes { DiasporaFederation::Engine.routes }
diff --git a/spec/controllers/diaspora_federation/h_card_controller_spec.rb b/spec/controllers/diaspora_federation/h_card_controller_spec.rb
index 4bb4529..1cf805b 100644
--- a/spec/controllers/diaspora_federation/h_card_controller_spec.rb
+++ b/spec/controllers/diaspora_federation/h_card_controller_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe HCardController, type: :controller do
     routes { DiasporaFederation::Engine.routes }
diff --git a/spec/controllers/diaspora_federation/receive_controller_spec.rb b/spec/controllers/diaspora_federation/receive_controller_spec.rb
index 281319e..0d5b684 100644
--- a/spec/controllers/diaspora_federation/receive_controller_spec.rb
+++ b/spec/controllers/diaspora_federation/receive_controller_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe ReceiveController, type: :controller do
     routes { DiasporaFederation::Engine.routes }
@@ -38,7 +40,7 @@ module DiasporaFederation
         it "returns a 202 if queued correctly" do
           expect_callback(:queue_public_receive, "<me:env/>", false)
 
-          post :public, body: "<me:env/>"
+          post :public, body: +"<me:env/>"
           expect(response.code).to eq("202")
         end
       end
@@ -89,7 +91,7 @@ module DiasporaFederation
           ).and_return(false)
 
           post :private,
-               body:   "{\"aes_key\": \"key\", \"encrypted_magic_envelope\": \"env\"}",
+               body:   +"{\"aes_key\": \"key\", \"encrypted_magic_envelope\": \"env\"}",
                params: {guid: "any-guid"}
           expect(response.code).to eq("404")
         end
@@ -100,7 +102,7 @@ module DiasporaFederation
           ).and_return(true)
 
           post :private,
-               body:   "{\"aes_key\": \"key\", \"encrypted_magic_envelope\": \"env\"}",
+               body:   +"{\"aes_key\": \"key\", \"encrypted_magic_envelope\": \"env\"}",
                params: {guid: "any-guid"}
           expect(response.code).to eq("202")
         end
diff --git a/spec/controllers/diaspora_federation/webfinger_controller_spec.rb b/spec/controllers/diaspora_federation/webfinger_controller_spec.rb
index 335c19e..c1a4fa1 100644
--- a/spec/controllers/diaspora_federation/webfinger_controller_spec.rb
+++ b/spec/controllers/diaspora_federation/webfinger_controller_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe WebfingerController, type: :controller do
     routes { DiasporaFederation::Engine.routes }
diff --git a/spec/entities.rb b/spec/entities.rb
index c370a91..429ea8a 100644
--- a/spec/entities.rb
+++ b/spec/entities.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   module Entities
     class TestEntity < DiasporaFederation::Entity
@@ -70,7 +72,7 @@ module DiasporaFederation
     end
 
     class SomeRelayable < DiasporaFederation::Entity
-      PARENT_TYPE = "Parent".freeze
+      PARENT_TYPE = "Parent"
 
       include Entities::Relayable
 
@@ -78,7 +80,7 @@ module DiasporaFederation
     end
 
     class TestRelayableWithBoolean < DiasporaFederation::Entity
-      PARENT_TYPE = "Parent".freeze
+      PARENT_TYPE = "Parent"
 
       include Entities::Relayable
 
diff --git a/spec/factories.rb b/spec/factories.rb
index 8bd3e67..bbba632 100644
--- a/spec/factories.rb
+++ b/spec/factories.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "diaspora_federation/test/factories"
 
 Fabricator(:person) do
diff --git a/spec/integration/comment_integration_spec.rb b/spec/integration/comment_integration_spec.rb
index 838f7b4..085a318 100644
--- a/spec/integration/comment_integration_spec.rb
+++ b/spec/integration/comment_integration_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::Relayable do
     let(:author_serialized_key) { <<-KEY }
diff --git a/spec/lib/diaspora_federation/callbacks_spec.rb b/spec/lib/diaspora_federation/callbacks_spec.rb
index e6adfe8..80e0ff3 100644
--- a/spec/lib/diaspora_federation/callbacks_spec.rb
+++ b/spec/lib/diaspora_federation/callbacks_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Callbacks do
     subject(:callbacks) { Callbacks.new %i[some_event another_event] }
diff --git a/spec/lib/diaspora_federation/discovery/discovery_spec.rb b/spec/lib/diaspora_federation/discovery/discovery_spec.rb
index 7ee024e..d298d04 100644
--- a/spec/lib/diaspora_federation/discovery/discovery_spec.rb
+++ b/spec/lib/diaspora_federation/discovery/discovery_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Discovery::Discovery do
     let(:host_meta_xrd) { Discovery::HostMeta.from_base_url("http://localhost:3000/").to_xml }
diff --git a/spec/lib/diaspora_federation/discovery/h_card_spec.rb b/spec/lib/diaspora_federation/discovery/h_card_spec.rb
index 5644891..22456db 100644
--- a/spec/lib/diaspora_federation/discovery/h_card_spec.rb
+++ b/spec/lib/diaspora_federation/discovery/h_card_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Discovery::HCard do
     let(:person) { Fabricate(:person) }
diff --git a/spec/lib/diaspora_federation/discovery/host_meta_spec.rb b/spec/lib/diaspora_federation/discovery/host_meta_spec.rb
index aeb6fa6..afd351b 100644
--- a/spec/lib/diaspora_federation/discovery/host_meta_spec.rb
+++ b/spec/lib/diaspora_federation/discovery/host_meta_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Discovery::HostMeta do
     let(:base_url) { "https://pod.example.tld/" }
diff --git a/spec/lib/diaspora_federation/discovery/web_finger_spec.rb b/spec/lib/diaspora_federation/discovery/web_finger_spec.rb
index fb0a2a4..96f7c3e 100644
--- a/spec/lib/diaspora_federation/discovery/web_finger_spec.rb
+++ b/spec/lib/diaspora_federation/discovery/web_finger_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Discovery::WebFinger do
     let(:person) { Fabricate(:person) }
diff --git a/spec/lib/diaspora_federation/discovery/xrd_document_spec.rb b/spec/lib/diaspora_federation/discovery/xrd_document_spec.rb
index 3fe8a3b..30ecc05 100644
--- a/spec/lib/diaspora_federation/discovery/xrd_document_spec.rb
+++ b/spec/lib/diaspora_federation/discovery/xrd_document_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Discovery::XrdDocument do
     let(:xml) { <<-XML }
diff --git a/spec/lib/diaspora_federation/entities/account_deletion_spec.rb b/spec/lib/diaspora_federation/entities/account_deletion_spec.rb
index 1de2ecf..0105e15 100644
--- a/spec/lib/diaspora_federation/entities/account_deletion_spec.rb
+++ b/spec/lib/diaspora_federation/entities/account_deletion_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::AccountDeletion do
     let(:data) { Fabricate.attributes_for(:account_deletion_entity) }
diff --git a/spec/lib/diaspora_federation/entities/account_migration/signable_spec.rb b/spec/lib/diaspora_federation/entities/account_migration/signable_spec.rb
index 5b6b784..0d150d9 100644
--- a/spec/lib/diaspora_federation/entities/account_migration/signable_spec.rb
+++ b/spec/lib/diaspora_federation/entities/account_migration/signable_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::AccountMigration::Signable do
     let(:entity) { TestAMSignableEntity.new({}) }
diff --git a/spec/lib/diaspora_federation/entities/account_migration_spec.rb b/spec/lib/diaspora_federation/entities/account_migration_spec.rb
index 37852df..d6b9e8e 100644
--- a/spec/lib/diaspora_federation/entities/account_migration_spec.rb
+++ b/spec/lib/diaspora_federation/entities/account_migration_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::AccountMigration do
     let(:old_user) { Fabricate(:user) }
diff --git a/spec/lib/diaspora_federation/entities/comment_spec.rb b/spec/lib/diaspora_federation/entities/comment_spec.rb
index 1263510..c2da543 100644
--- a/spec/lib/diaspora_federation/entities/comment_spec.rb
+++ b/spec/lib/diaspora_federation/entities/comment_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::Comment do
     let(:parent) { Fabricate(:post, author: bob) }
diff --git a/spec/lib/diaspora_federation/entities/contact_spec.rb b/spec/lib/diaspora_federation/entities/contact_spec.rb
index aea9ef8..f0a29ca 100644
--- a/spec/lib/diaspora_federation/entities/contact_spec.rb
+++ b/spec/lib/diaspora_federation/entities/contact_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::Contact do
     let(:data) { Fabricate.attributes_for(:contact_entity) }
diff --git a/spec/lib/diaspora_federation/entities/conversation_spec.rb b/spec/lib/diaspora_federation/entities/conversation_spec.rb
index 0c263b0..9495c90 100644
--- a/spec/lib/diaspora_federation/entities/conversation_spec.rb
+++ b/spec/lib/diaspora_federation/entities/conversation_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::Conversation do
     let(:parent) { Fabricate(:conversation, author: bob) }
diff --git a/spec/lib/diaspora_federation/entities/embed_spec.rb b/spec/lib/diaspora_federation/entities/embed_spec.rb
index 7b857e4..5475aca 100644
--- a/spec/lib/diaspora_federation/entities/embed_spec.rb
+++ b/spec/lib/diaspora_federation/entities/embed_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::Embed do
     let(:data) { Fabricate.attributes_for(:embed_entity) }
diff --git a/spec/lib/diaspora_federation/entities/event_participation_spec.rb b/spec/lib/diaspora_federation/entities/event_participation_spec.rb
index b6c7ce1..6a399b4 100644
--- a/spec/lib/diaspora_federation/entities/event_participation_spec.rb
+++ b/spec/lib/diaspora_federation/entities/event_participation_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::EventParticipation do
     let(:parent) { Fabricate(:event, author: bob) }
diff --git a/spec/lib/diaspora_federation/entities/event_spec.rb b/spec/lib/diaspora_federation/entities/event_spec.rb
index 29f5e77..492d921 100644
--- a/spec/lib/diaspora_federation/entities/event_spec.rb
+++ b/spec/lib/diaspora_federation/entities/event_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::Event do
     let(:location) { Fabricate(:location_entity) }
diff --git a/spec/lib/diaspora_federation/entities/like_spec.rb b/spec/lib/diaspora_federation/entities/like_spec.rb
index 5983c94..10d6101 100644
--- a/spec/lib/diaspora_federation/entities/like_spec.rb
+++ b/spec/lib/diaspora_federation/entities/like_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::Like do
     let(:parent) { Fabricate(:post, author: bob) }
diff --git a/spec/lib/diaspora_federation/entities/location_spec.rb b/spec/lib/diaspora_federation/entities/location_spec.rb
index 0ba629e..9a7d48e 100644
--- a/spec/lib/diaspora_federation/entities/location_spec.rb
+++ b/spec/lib/diaspora_federation/entities/location_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::Location do
     let(:data) { Fabricate.attributes_for(:location_entity) }
diff --git a/spec/lib/diaspora_federation/entities/message_spec.rb b/spec/lib/diaspora_federation/entities/message_spec.rb
index d8aa86d..ea06f25 100644
--- a/spec/lib/diaspora_federation/entities/message_spec.rb
+++ b/spec/lib/diaspora_federation/entities/message_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::Message do
     let(:data) { Fabricate.attributes_for(:message_entity, author: alice.diaspora_id) }
diff --git a/spec/lib/diaspora_federation/entities/participation_spec.rb b/spec/lib/diaspora_federation/entities/participation_spec.rb
index 819e4a0..ae021b9 100644
--- a/spec/lib/diaspora_federation/entities/participation_spec.rb
+++ b/spec/lib/diaspora_federation/entities/participation_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::Participation do
     let(:parent) { Fabricate(:post, author: bob) }
diff --git a/spec/lib/diaspora_federation/entities/person_spec.rb b/spec/lib/diaspora_federation/entities/person_spec.rb
index 615a41e..ae0a100 100644
--- a/spec/lib/diaspora_federation/entities/person_spec.rb
+++ b/spec/lib/diaspora_federation/entities/person_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::Person do
     let(:data) { Fabricate.attributes_for(:person_entity) }
diff --git a/spec/lib/diaspora_federation/entities/photo_spec.rb b/spec/lib/diaspora_federation/entities/photo_spec.rb
index 742f3f9..55e7556 100644
--- a/spec/lib/diaspora_federation/entities/photo_spec.rb
+++ b/spec/lib/diaspora_federation/entities/photo_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::Photo do
     let(:data) { Fabricate.attributes_for(:photo_entity) }
diff --git a/spec/lib/diaspora_federation/entities/poll_answer_spec.rb b/spec/lib/diaspora_federation/entities/poll_answer_spec.rb
index b16d23e..db0120d 100644
--- a/spec/lib/diaspora_federation/entities/poll_answer_spec.rb
+++ b/spec/lib/diaspora_federation/entities/poll_answer_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::PollAnswer do
     let(:data) { Fabricate.attributes_for(:poll_answer_entity) }
diff --git a/spec/lib/diaspora_federation/entities/poll_participation_spec.rb b/spec/lib/diaspora_federation/entities/poll_participation_spec.rb
index 424d767..0530357 100644
--- a/spec/lib/diaspora_federation/entities/poll_participation_spec.rb
+++ b/spec/lib/diaspora_federation/entities/poll_participation_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::PollParticipation do
     let(:parent) { Fabricate(:poll, author: bob) }
diff --git a/spec/lib/diaspora_federation/entities/poll_spec.rb b/spec/lib/diaspora_federation/entities/poll_spec.rb
index 2065785..5ca60f1 100644
--- a/spec/lib/diaspora_federation/entities/poll_spec.rb
+++ b/spec/lib/diaspora_federation/entities/poll_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::Poll do
     let(:data) { Fabricate.attributes_for(:poll_entity) }
diff --git a/spec/lib/diaspora_federation/entities/profile_spec.rb b/spec/lib/diaspora_federation/entities/profile_spec.rb
index fa42faf..62b3887 100644
--- a/spec/lib/diaspora_federation/entities/profile_spec.rb
+++ b/spec/lib/diaspora_federation/entities/profile_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::Profile do
     let(:data) { Fabricate.attributes_for(:profile_entity) }
diff --git a/spec/lib/diaspora_federation/entities/related_entity_spec.rb b/spec/lib/diaspora_federation/entities/related_entity_spec.rb
index 902eab3..7b02c81 100644
--- a/spec/lib/diaspora_federation/entities/related_entity_spec.rb
+++ b/spec/lib/diaspora_federation/entities/related_entity_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::RelatedEntity do
     let(:data) { Fabricate.attributes_for(:related_entity) }
diff --git a/spec/lib/diaspora_federation/entities/relayable_retraction_spec.rb b/spec/lib/diaspora_federation/entities/relayable_retraction_spec.rb
index 09bfce4..ed4108c 100644
--- a/spec/lib/diaspora_federation/entities/relayable_retraction_spec.rb
+++ b/spec/lib/diaspora_federation/entities/relayable_retraction_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::RelayableRetraction do
     let(:target) { Fabricate(:comment, author: bob) }
diff --git a/spec/lib/diaspora_federation/entities/relayable_spec.rb b/spec/lib/diaspora_federation/entities/relayable_spec.rb
index f80e143..33da867 100644
--- a/spec/lib/diaspora_federation/entities/relayable_spec.rb
+++ b/spec/lib/diaspora_federation/entities/relayable_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::Relayable do
     let(:author_pkey) { OpenSSL::PKey::RSA.generate(1024) }
diff --git a/spec/lib/diaspora_federation/entities/request_spec.rb b/spec/lib/diaspora_federation/entities/request_spec.rb
index 1826217..8d28435 100644
--- a/spec/lib/diaspora_federation/entities/request_spec.rb
+++ b/spec/lib/diaspora_federation/entities/request_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::Request do
     let(:data) { {author: Fabricate.sequence(:diaspora_id), recipient: Fabricate.sequence(:diaspora_id)} }
diff --git a/spec/lib/diaspora_federation/entities/reshare_spec.rb b/spec/lib/diaspora_federation/entities/reshare_spec.rb
index 7a15a85..518c66c 100644
--- a/spec/lib/diaspora_federation/entities/reshare_spec.rb
+++ b/spec/lib/diaspora_federation/entities/reshare_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::Reshare do
     let(:root) { Fabricate(:post, author: bob) }
diff --git a/spec/lib/diaspora_federation/entities/retraction_spec.rb b/spec/lib/diaspora_federation/entities/retraction_spec.rb
index c3d1e9d..3f7b690 100644
--- a/spec/lib/diaspora_federation/entities/retraction_spec.rb
+++ b/spec/lib/diaspora_federation/entities/retraction_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::Retraction do
     let(:target) { Fabricate(:post, author: bob) }
diff --git a/spec/lib/diaspora_federation/entities/signable_spec.rb b/spec/lib/diaspora_federation/entities/signable_spec.rb
index 6ae9e7f..051e52a 100644
--- a/spec/lib/diaspora_federation/entities/signable_spec.rb
+++ b/spec/lib/diaspora_federation/entities/signable_spec.rb
@@ -1,6 +1,8 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::Signable do
-    TEST_STRING_VALUE = "abc123".freeze
+    TEST_STRING_VALUE = "abc123"
 
     class TestSignableEntity < Entity
       include Entities::Signable
diff --git a/spec/lib/diaspora_federation/entities/signed_retraction_spec.rb b/spec/lib/diaspora_federation/entities/signed_retraction_spec.rb
index 0547299..8fdb1c5 100644
--- a/spec/lib/diaspora_federation/entities/signed_retraction_spec.rb
+++ b/spec/lib/diaspora_federation/entities/signed_retraction_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::SignedRetraction do
     let(:target) { Fabricate(:post, author: alice) }
diff --git a/spec/lib/diaspora_federation/entities/status_message_spec.rb b/spec/lib/diaspora_federation/entities/status_message_spec.rb
index 4fe600a..4a07258 100644
--- a/spec/lib/diaspora_federation/entities/status_message_spec.rb
+++ b/spec/lib/diaspora_federation/entities/status_message_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entities::StatusMessage do
     let(:photo1) { Fabricate(:photo_entity, author: alice.diaspora_id) }
diff --git a/spec/lib/diaspora_federation/entity_spec.rb b/spec/lib/diaspora_federation/entity_spec.rb
index 3039338..63964b0 100644
--- a/spec/lib/diaspora_federation/entity_spec.rb
+++ b/spec/lib/diaspora_federation/entity_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Entity do
     let(:data) { {test1: "asdf", test2: 1234, test3: false, test4: false} }
diff --git a/spec/lib/diaspora_federation/federation/diaspora_url_parser_spec.rb b/spec/lib/diaspora_federation/federation/diaspora_url_parser_spec.rb
index 2649d80..dee3354 100644
--- a/spec/lib/diaspora_federation/federation/diaspora_url_parser_spec.rb
+++ b/spec/lib/diaspora_federation/federation/diaspora_url_parser_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Federation::DiasporaUrlParser do
     let(:author) { Fabricate.sequence(:diaspora_id) }
diff --git a/spec/lib/diaspora_federation/federation/fetcher_spec.rb b/spec/lib/diaspora_federation/federation/fetcher_spec.rb
index 51997eb..d1cdd8f 100644
--- a/spec/lib/diaspora_federation/federation/fetcher_spec.rb
+++ b/spec/lib/diaspora_federation/federation/fetcher_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Federation::Fetcher do
     let(:post) { Fabricate(:status_message_entity, public: true) }
diff --git a/spec/lib/diaspora_federation/federation/receiver/private_spec.rb b/spec/lib/diaspora_federation/federation/receiver/private_spec.rb
index e0fbb37..8d9cb6a 100644
--- a/spec/lib/diaspora_federation/federation/receiver/private_spec.rb
+++ b/spec/lib/diaspora_federation/federation/receiver/private_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Federation::Receiver::Private do
     let(:recipient) { 42 }
diff --git a/spec/lib/diaspora_federation/federation/receiver/public_spec.rb b/spec/lib/diaspora_federation/federation/receiver/public_spec.rb
index 9815490..5aa3220 100644
--- a/spec/lib/diaspora_federation/federation/receiver/public_spec.rb
+++ b/spec/lib/diaspora_federation/federation/receiver/public_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Federation::Receiver::Public do
     let(:post) { Fabricate(:status_message_entity) }
diff --git a/spec/lib/diaspora_federation/federation/receiver_spec.rb b/spec/lib/diaspora_federation/federation/receiver_spec.rb
index 5779a37..b5b2d33 100644
--- a/spec/lib/diaspora_federation/federation/receiver_spec.rb
+++ b/spec/lib/diaspora_federation/federation/receiver_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Federation::Receiver do
     let(:sender_key) { OpenSSL::PKey::RSA.generate(1024) }
diff --git a/spec/lib/diaspora_federation/federation/sender/hydra_wrapper_spec.rb b/spec/lib/diaspora_federation/federation/sender/hydra_wrapper_spec.rb
index 66f9698..170729e 100644
--- a/spec/lib/diaspora_federation/federation/sender/hydra_wrapper_spec.rb
+++ b/spec/lib/diaspora_federation/federation/sender/hydra_wrapper_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Federation::Sender::HydraWrapper do
     let(:sender_id) { Fabricate.sequence(:diaspora_id) }
diff --git a/spec/lib/diaspora_federation/federation/sender_spec.rb b/spec/lib/diaspora_federation/federation/sender_spec.rb
index 8f1dce9..0a8e3ad 100644
--- a/spec/lib/diaspora_federation/federation/sender_spec.rb
+++ b/spec/lib/diaspora_federation/federation/sender_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Federation::Sender do
     let(:sender_id) { Fabricate.sequence(:diaspora_id) }
diff --git a/spec/lib/diaspora_federation/http_client_spec.rb b/spec/lib/diaspora_federation/http_client_spec.rb
index 00efe91..5a4c5a7 100644
--- a/spec/lib/diaspora_federation/http_client_spec.rb
+++ b/spec/lib/diaspora_federation/http_client_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe HttpClient do
     describe ".get" do
diff --git a/spec/lib/diaspora_federation/parsers/base_parser_spec.rb b/spec/lib/diaspora_federation/parsers/base_parser_spec.rb
index 1fdf683..17a3c17 100644
--- a/spec/lib/diaspora_federation/parsers/base_parser_spec.rb
+++ b/spec/lib/diaspora_federation/parsers/base_parser_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Parsers::BaseParser do
     describe ".parse" do
diff --git a/spec/lib/diaspora_federation/parsers/json_parser_spec.rb b/spec/lib/diaspora_federation/parsers/json_parser_spec.rb
index 0758395..e73d796 100644
--- a/spec/lib/diaspora_federation/parsers/json_parser_spec.rb
+++ b/spec/lib/diaspora_federation/parsers/json_parser_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Parsers::JsonParser do
     describe ".parse" do
diff --git a/spec/lib/diaspora_federation/parsers/relayable_json_parser_spec.rb b/spec/lib/diaspora_federation/parsers/relayable_json_parser_spec.rb
index bab94ff..7b9fef4 100644
--- a/spec/lib/diaspora_federation/parsers/relayable_json_parser_spec.rb
+++ b/spec/lib/diaspora_federation/parsers/relayable_json_parser_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Parsers::RelayableJsonParser do
     describe ".parse" do
diff --git a/spec/lib/diaspora_federation/parsers/relayable_xml_parser_spec.rb b/spec/lib/diaspora_federation/parsers/relayable_xml_parser_spec.rb
index d3f524e..e7159ca 100644
--- a/spec/lib/diaspora_federation/parsers/relayable_xml_parser_spec.rb
+++ b/spec/lib/diaspora_federation/parsers/relayable_xml_parser_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Parsers::RelayableXmlParser do
     describe ".parse" do
diff --git a/spec/lib/diaspora_federation/parsers/xml_parser_spec.rb b/spec/lib/diaspora_federation/parsers/xml_parser_spec.rb
index fdcf4b6..14c5544 100644
--- a/spec/lib/diaspora_federation/parsers/xml_parser_spec.rb
+++ b/spec/lib/diaspora_federation/parsers/xml_parser_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Parsers::XmlParser do
     describe ".parse" do
diff --git a/spec/lib/diaspora_federation/properties_dsl_spec.rb b/spec/lib/diaspora_federation/properties_dsl_spec.rb
index d7ce682..f5ff9ee 100644
--- a/spec/lib/diaspora_federation/properties_dsl_spec.rb
+++ b/spec/lib/diaspora_federation/properties_dsl_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe PropertiesDSL do
     subject(:dsl) { Class.new.extend(PropertiesDSL) }
diff --git a/spec/lib/diaspora_federation/salmon/aes_spec.rb b/spec/lib/diaspora_federation/salmon/aes_spec.rb
index cd0db9e..8fa5af0 100644
--- a/spec/lib/diaspora_federation/salmon/aes_spec.rb
+++ b/spec/lib/diaspora_federation/salmon/aes_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Salmon::AES do
     let(:data) { "test data string" }
diff --git a/spec/lib/diaspora_federation/salmon/encrypted_magic_envelope_spec.rb b/spec/lib/diaspora_federation/salmon/encrypted_magic_envelope_spec.rb
index 7b5f264..de6d97a 100644
--- a/spec/lib/diaspora_federation/salmon/encrypted_magic_envelope_spec.rb
+++ b/spec/lib/diaspora_federation/salmon/encrypted_magic_envelope_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Salmon::EncryptedMagicEnvelope do
     let(:sender_id) { Fabricate.sequence(:diaspora_id) }
diff --git a/spec/lib/diaspora_federation/salmon/encrypted_slap_spec.rb b/spec/lib/diaspora_federation/salmon/encrypted_slap_spec.rb
index 43349f0..a806936 100644
--- a/spec/lib/diaspora_federation/salmon/encrypted_slap_spec.rb
+++ b/spec/lib/diaspora_federation/salmon/encrypted_slap_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Salmon::EncryptedSlap do
     let(:sender) { "user_test@diaspora.example.tld" }
diff --git a/spec/lib/diaspora_federation/salmon/magic_envelope_spec.rb b/spec/lib/diaspora_federation/salmon/magic_envelope_spec.rb
index 01d28e5..b3f1b27 100644
--- a/spec/lib/diaspora_federation/salmon/magic_envelope_spec.rb
+++ b/spec/lib/diaspora_federation/salmon/magic_envelope_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Salmon::MagicEnvelope do
     let(:sender) { Fabricate.sequence(:diaspora_id) }
diff --git a/spec/lib/diaspora_federation/salmon/slap_spec.rb b/spec/lib/diaspora_federation/salmon/slap_spec.rb
index 465f827..7e5e349 100644
--- a/spec/lib/diaspora_federation/salmon/slap_spec.rb
+++ b/spec/lib/diaspora_federation/salmon/slap_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Salmon::Slap do
     let(:sender) { "test_user@pod.somedomain.tld" }
diff --git a/spec/lib/diaspora_federation/salmon/xml_payload_spec.rb b/spec/lib/diaspora_federation/salmon/xml_payload_spec.rb
index c254580..cf60f83 100644
--- a/spec/lib/diaspora_federation/salmon/xml_payload_spec.rb
+++ b/spec/lib/diaspora_federation/salmon/xml_payload_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Salmon::XmlPayload do
     let(:entity) { Entities::TestEntity.new(test: "asdf") }
diff --git a/spec/lib/diaspora_federation/schemas_spec.rb b/spec/lib/diaspora_federation/schemas_spec.rb
index 4ac5107..f41c1a1 100644
--- a/spec/lib/diaspora_federation/schemas_spec.rb
+++ b/spec/lib/diaspora_federation/schemas_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "diaspora_federation/schemas"
 
 module DiasporaFederation
diff --git a/spec/lib/diaspora_federation/validators/account_deletion_validator_spec.rb b/spec/lib/diaspora_federation/validators/account_deletion_validator_spec.rb
index 2c76af6..78c5463 100644
--- a/spec/lib/diaspora_federation/validators/account_deletion_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/account_deletion_validator_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Validators::AccountDeletionValidator do
     let(:entity) { :account_deletion_entity }
diff --git a/spec/lib/diaspora_federation/validators/account_migration_validator_spec.rb b/spec/lib/diaspora_federation/validators/account_migration_validator_spec.rb
index e8c4ea5..77e0f0b 100644
--- a/spec/lib/diaspora_federation/validators/account_migration_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/account_migration_validator_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Validators::AccountMigrationValidator do
     let(:entity) { :account_migration_entity }
diff --git a/spec/lib/diaspora_federation/validators/comment_validator_spec.rb b/spec/lib/diaspora_federation/validators/comment_validator_spec.rb
index 5a0b0c5..34c3529 100644
--- a/spec/lib/diaspora_federation/validators/comment_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/comment_validator_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Validators::CommentValidator do
     let(:entity) { :comment_entity }
diff --git a/spec/lib/diaspora_federation/validators/contact_validator_spec.rb b/spec/lib/diaspora_federation/validators/contact_validator_spec.rb
index 1e5b926..171415e 100644
--- a/spec/lib/diaspora_federation/validators/contact_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/contact_validator_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Validators::ContactValidator do
     let(:entity) { :contact_entity }
diff --git a/spec/lib/diaspora_federation/validators/conversation_validator_spec.rb b/spec/lib/diaspora_federation/validators/conversation_validator_spec.rb
index d5f93a9..4a9f3da 100644
--- a/spec/lib/diaspora_federation/validators/conversation_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/conversation_validator_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Validators::ConversationValidator do
     let(:entity) { :conversation_entity }
diff --git a/spec/lib/diaspora_federation/validators/embed_validator_spec.rb b/spec/lib/diaspora_federation/validators/embed_validator_spec.rb
index d6045b3..d9639dc 100644
--- a/spec/lib/diaspora_federation/validators/embed_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/embed_validator_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Validators::EmbedValidator do
     let(:entity) { :embed_entity }
diff --git a/spec/lib/diaspora_federation/validators/event_participation_validator_spec.rb b/spec/lib/diaspora_federation/validators/event_participation_validator_spec.rb
index f7e1358..288f6ba 100644
--- a/spec/lib/diaspora_federation/validators/event_participation_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/event_participation_validator_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Validators::EventParticipationValidator do
     let(:entity) { :event_participation_entity }
diff --git a/spec/lib/diaspora_federation/validators/event_validator_spec.rb b/spec/lib/diaspora_federation/validators/event_validator_spec.rb
index c516a95..64efe53 100644
--- a/spec/lib/diaspora_federation/validators/event_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/event_validator_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Validators::EventValidator do
     let(:entity) { :event_entity }
diff --git a/spec/lib/diaspora_federation/validators/h_card_validator_spec.rb b/spec/lib/diaspora_federation/validators/h_card_validator_spec.rb
index ac70097..30f89dc 100644
--- a/spec/lib/diaspora_federation/validators/h_card_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/h_card_validator_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Validators::HCardValidator do
     let(:entity) { :h_card }
diff --git a/spec/lib/diaspora_federation/validators/like_validator_spec.rb b/spec/lib/diaspora_federation/validators/like_validator_spec.rb
index 34888d6..6529245 100644
--- a/spec/lib/diaspora_federation/validators/like_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/like_validator_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Validators::LikeValidator do
     let(:entity) { :like_entity }
diff --git a/spec/lib/diaspora_federation/validators/location_validator_spec.rb b/spec/lib/diaspora_federation/validators/location_validator_spec.rb
index 1b60840..ffe81da 100644
--- a/spec/lib/diaspora_federation/validators/location_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/location_validator_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Validators::LocationValidator do
     let(:entity) { :location_entity }
diff --git a/spec/lib/diaspora_federation/validators/message_validator_spec.rb b/spec/lib/diaspora_federation/validators/message_validator_spec.rb
index 0889cbb..571fd96 100644
--- a/spec/lib/diaspora_federation/validators/message_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/message_validator_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Validators::MessageValidator do
     let(:entity) { :message_entity }
diff --git a/spec/lib/diaspora_federation/validators/optional_aware_validator_spec.rb b/spec/lib/diaspora_federation/validators/optional_aware_validator_spec.rb
index 049ee49..047af2b 100644
--- a/spec/lib/diaspora_federation/validators/optional_aware_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/optional_aware_validator_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Validators::OptionalAwareValidator do
     def entity_stub(additional_data={})
diff --git a/spec/lib/diaspora_federation/validators/participation_validator_spec.rb b/spec/lib/diaspora_federation/validators/participation_validator_spec.rb
index 7ffdcfc..7983cea 100644
--- a/spec/lib/diaspora_federation/validators/participation_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/participation_validator_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Validators::ParticipationValidator do
     let(:entity) { :participation_entity }
diff --git a/spec/lib/diaspora_federation/validators/person_validator_spec.rb b/spec/lib/diaspora_federation/validators/person_validator_spec.rb
index 6b7d61d..e8c195f 100644
--- a/spec/lib/diaspora_federation/validators/person_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/person_validator_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Validators::PersonValidator do
     let(:entity) { :person_entity }
diff --git a/spec/lib/diaspora_federation/validators/photo_validator_spec.rb b/spec/lib/diaspora_federation/validators/photo_validator_spec.rb
index 342ebac..e55cfec 100644
--- a/spec/lib/diaspora_federation/validators/photo_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/photo_validator_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Validators::PhotoValidator do
     let(:entity) { :photo_entity }
diff --git a/spec/lib/diaspora_federation/validators/poll_answer_validator_spec.rb b/spec/lib/diaspora_federation/validators/poll_answer_validator_spec.rb
index be1d1e5..f849017 100644
--- a/spec/lib/diaspora_federation/validators/poll_answer_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/poll_answer_validator_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Validators::PollAnswerValidator do
     let(:entity) { :poll_answer_entity }
diff --git a/spec/lib/diaspora_federation/validators/poll_participation_validator_spec.rb b/spec/lib/diaspora_federation/validators/poll_participation_validator_spec.rb
index 51215d8..95581ef 100644
--- a/spec/lib/diaspora_federation/validators/poll_participation_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/poll_participation_validator_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Validators::PollParticipationValidator do
     let(:entity) { :poll_participation_entity }
diff --git a/spec/lib/diaspora_federation/validators/poll_validator_spec.rb b/spec/lib/diaspora_federation/validators/poll_validator_spec.rb
index 2b26b55..d1fd0b7 100644
--- a/spec/lib/diaspora_federation/validators/poll_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/poll_validator_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Validators::PollValidator do
     let(:entity) { :poll_entity }
diff --git a/spec/lib/diaspora_federation/validators/profile_validator_spec.rb b/spec/lib/diaspora_federation/validators/profile_validator_spec.rb
index c9c4e7c..79c5106 100644
--- a/spec/lib/diaspora_federation/validators/profile_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/profile_validator_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Validators::ProfileValidator do
     let(:entity) { :profile_entity }
diff --git a/spec/lib/diaspora_federation/validators/related_entity_validator_spec.rb b/spec/lib/diaspora_federation/validators/related_entity_validator_spec.rb
index 56bf669..654b875 100644
--- a/spec/lib/diaspora_federation/validators/related_entity_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/related_entity_validator_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Validators::RelatedEntityValidator do
     let(:entity) { :related_entity }
diff --git a/spec/lib/diaspora_federation/validators/reshare_validator_spec.rb b/spec/lib/diaspora_federation/validators/reshare_validator_spec.rb
index 6909ed6..6aaad65 100644
--- a/spec/lib/diaspora_federation/validators/reshare_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/reshare_validator_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Validators::ReshareValidator do
     let(:entity) { :reshare_entity }
diff --git a/spec/lib/diaspora_federation/validators/retraction_validator_spec.rb b/spec/lib/diaspora_federation/validators/retraction_validator_spec.rb
index b19294c..917b8d6 100644
--- a/spec/lib/diaspora_federation/validators/retraction_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/retraction_validator_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Validators::RetractionValidator do
     let(:entity) { :retraction_entity }
diff --git a/spec/lib/diaspora_federation/validators/rules/birthday_spec.rb b/spec/lib/diaspora_federation/validators/rules/birthday_spec.rb
index 8ed274d..cdee654 100644
--- a/spec/lib/diaspora_federation/validators/rules/birthday_spec.rb
+++ b/spec/lib/diaspora_federation/validators/rules/birthday_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 describe Validation::Rule::Birthday do
   it "will not accept parameters" do
     validator = Validation::Validator.new({})
diff --git a/spec/lib/diaspora_federation/validators/rules/boolean_spec.rb b/spec/lib/diaspora_federation/validators/rules/boolean_spec.rb
index cf95e1b..5151739 100644
--- a/spec/lib/diaspora_federation/validators/rules/boolean_spec.rb
+++ b/spec/lib/diaspora_federation/validators/rules/boolean_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 describe Validation::Rule::Boolean do
   it "will not accept parameters" do
     validator = Validation::Validator.new({})
diff --git a/spec/lib/diaspora_federation/validators/rules/diaspora_id_list_spec.rb b/spec/lib/diaspora_federation/validators/rules/diaspora_id_list_spec.rb
index d6ad026..1030d37 100644
--- a/spec/lib/diaspora_federation/validators/rules/diaspora_id_list_spec.rb
+++ b/spec/lib/diaspora_federation/validators/rules/diaspora_id_list_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 describe Validation::Rule::DiasporaIdList do
   let(:id_str) { Array.new(3) { Fabricate.sequence(:diaspora_id) }.join(";") }
 
diff --git a/spec/lib/diaspora_federation/validators/rules/diaspora_id_spec.rb b/spec/lib/diaspora_federation/validators/rules/diaspora_id_spec.rb
index a796530..d824d9f 100644
--- a/spec/lib/diaspora_federation/validators/rules/diaspora_id_spec.rb
+++ b/spec/lib/diaspora_federation/validators/rules/diaspora_id_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 describe Validation::Rule::DiasporaId do
   it "will not accept parameters" do
     validator = Validation::Validator.new({})
diff --git a/spec/lib/diaspora_federation/validators/rules/guid_spec.rb b/spec/lib/diaspora_federation/validators/rules/guid_spec.rb
index 3a71404..779bc1d 100644
--- a/spec/lib/diaspora_federation/validators/rules/guid_spec.rb
+++ b/spec/lib/diaspora_federation/validators/rules/guid_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 describe Validation::Rule::Guid do
   it "will not accept parameters" do
     validator = Validation::Validator.new({})
diff --git a/spec/lib/diaspora_federation/validators/rules/not_nil_spec.rb b/spec/lib/diaspora_federation/validators/rules/not_nil_spec.rb
index 62709c9..7c10359 100644
--- a/spec/lib/diaspora_federation/validators/rules/not_nil_spec.rb
+++ b/spec/lib/diaspora_federation/validators/rules/not_nil_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 describe Validation::Rule::NotNil do
   it "will not accept parameters" do
     validator = Validation::Validator.new({})
diff --git a/spec/lib/diaspora_federation/validators/rules/public_key_spec.rb b/spec/lib/diaspora_federation/validators/rules/public_key_spec.rb
index ed3b1b6..1691fe6 100644
--- a/spec/lib/diaspora_federation/validators/rules/public_key_spec.rb
+++ b/spec/lib/diaspora_federation/validators/rules/public_key_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 describe Validation::Rule::PublicKey do
   it "will not accept parameters" do
     validator = Validation::Validator.new({})
diff --git a/spec/lib/diaspora_federation/validators/rules/tag_count_spec.rb b/spec/lib/diaspora_federation/validators/rules/tag_count_spec.rb
index 52e8720..b7fb86a 100644
--- a/spec/lib/diaspora_federation/validators/rules/tag_count_spec.rb
+++ b/spec/lib/diaspora_federation/validators/rules/tag_count_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 describe Validation::Rule::TagCount do
   it "requires a parameter" do
     validator = Validation::Validator.new({})
diff --git a/spec/lib/diaspora_federation/validators/status_message_validator_spec.rb b/spec/lib/diaspora_federation/validators/status_message_validator_spec.rb
index 0f8bd4b..26f9bfc 100644
--- a/spec/lib/diaspora_federation/validators/status_message_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/status_message_validator_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Validators::StatusMessageValidator do
     let(:entity) { :status_message_entity }
diff --git a/spec/lib/diaspora_federation/validators/web_finger_validator_spec.rb b/spec/lib/diaspora_federation/validators/web_finger_validator_spec.rb
index 8aaf77b..a7aac23 100644
--- a/spec/lib/diaspora_federation/validators/web_finger_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/web_finger_validator_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe Validators::WebFingerValidator do
     let(:entity) { :webfinger }
diff --git a/spec/lib/diaspora_federation_spec.rb b/spec/lib/diaspora_federation_spec.rb
index 4451309..e95fe6e 100644
--- a/spec/lib/diaspora_federation_spec.rb
+++ b/spec/lib/diaspora_federation_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe DiasporaFederation do
     context "validate_config" do
diff --git a/spec/routing/fetch_routing_spec.rb b/spec/routing/fetch_routing_spec.rb
index e8c50fe..6dfdb28 100644
--- a/spec/routing/fetch_routing_spec.rb
+++ b/spec/routing/fetch_routing_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe ReceiveController, type: :routing do
     routes { DiasporaFederation::Engine.routes }
diff --git a/spec/routing/receive_routing_spec.rb b/spec/routing/receive_routing_spec.rb
index 87a53b9..a0afc20 100644
--- a/spec/routing/receive_routing_spec.rb
+++ b/spec/routing/receive_routing_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe ReceiveController, type: :routing do
     routes { DiasporaFederation::Engine.routes }
diff --git a/spec/routing/webfinger_routing_spec.rb b/spec/routing/webfinger_routing_spec.rb
index 11f845a..9b1f33b 100644
--- a/spec/routing/webfinger_routing_spec.rb
+++ b/spec/routing/webfinger_routing_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DiasporaFederation
   describe ReceiveController, type: :routing do
     routes { DiasporaFederation::Engine.routes }
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index f7d6477..f20a729 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 unless ENV["NO_COVERAGE"] == "true"
   require "simplecov"
   require "simplecov-rcov"
diff --git a/spec/support/fixture_builder.rb b/spec/support/fixture_builder.rb
index 0e536d5..df473cc 100644
--- a/spec/support/fixture_builder.rb
+++ b/spec/support/fixture_builder.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # set default users as initial database for each test
 RSpec.configure do |config|
   config.before(:suite) do
diff --git a/spec/support/helper_methods.rb b/spec/support/helper_methods.rb
index 12a6f18..b2bb3a6 100644
--- a/spec/support/helper_methods.rb
+++ b/spec/support/helper_methods.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # default users
 def alice
   @alice ||= Person.find_by(diaspora_id: "alice@localhost:3000")
diff --git a/spec/support/legacy_helper.rb b/spec/support/legacy_helper.rb
index 384f43b..d938530 100644
--- a/spec/support/legacy_helper.rb
+++ b/spec/support/legacy_helper.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # This file only exists to generate legacy XMLs to test that we can still parse it.
 
 def generate_legacy_salmon_slap(entity, sender, sender_privkey)
diff --git a/spec/support/shared_entity_specs.rb b/spec/support/shared_entity_specs.rb
index a62eaf2..4c7ad42 100644
--- a/spec/support/shared_entity_specs.rb
+++ b/spec/support/shared_entity_specs.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 def entity_hash_from(hash)
   hash.delete(:parent_author_signature)
   hash.map {|key, value|
diff --git a/spec/support/shared_magic_envelope_specs.rb b/spec/support/shared_magic_envelope_specs.rb
index cbfcde3..41ba7fc 100644
--- a/spec/support/shared_magic_envelope_specs.rb
+++ b/spec/support/shared_magic_envelope_specs.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 shared_examples "a MagicEnvelope instance" do
   before do
     allow(DiasporaFederation.callbacks).to receive(:trigger).with(
diff --git a/spec/support/shared_parser_specs.rb b/spec/support/shared_parser_specs.rb
index f5cb26c..96e67f3 100644
--- a/spec/support/shared_parser_specs.rb
+++ b/spec/support/shared_parser_specs.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 shared_examples ".parse parse error" do |reason, json|
   it "raises error when #{reason}" do
     expect {
diff --git a/spec/support/shared_signable_specs.rb b/spec/support/shared_signable_specs.rb
index 8e5140d..3a0619c 100644
--- a/spec/support/shared_signable_specs.rb
+++ b/spec/support/shared_signable_specs.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 shared_examples "a signable" do
   let(:private_key) { OpenSSL::PKey::RSA.generate(1024) }
   let(:test_signature) { sign_with_key(private_key, test_string) }
diff --git a/spec/support/shared_validator_specs.rb b/spec/support/shared_validator_specs.rb
index 862148f..e8d240d 100644
--- a/spec/support/shared_validator_specs.rb
+++ b/spec/support/shared_validator_specs.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 def entity_stub(entity, data={})
   entity_class = Fabricate.schematic(entity).options[:class_name]
   allow_any_instance_of(entity_class).to receive(:freeze)
diff --git a/test/dummy/Rakefile b/test/dummy/Rakefile
index 08cc98f..dbf84da 100644
--- a/test/dummy/Rakefile
+++ b/test/dummy/Rakefile
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Add your own tasks in files placed in lib/tasks ending in .rake,
 # for example lib/tasks/capistrano.rake, and they will automatically be available to Rake.
 
diff --git a/test/dummy/app/models/entity.rb b/test/dummy/app/models/entity.rb
index 41135ed..3cbf562 100644
--- a/test/dummy/app/models/entity.rb
+++ b/test/dummy/app/models/entity.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Entity
   attr_accessor :author, :guid
   attr_reader :entity_type
diff --git a/test/dummy/app/models/person.rb b/test/dummy/app/models/person.rb
index cd96c6a..4083ef9 100644
--- a/test/dummy/app/models/person.rb
+++ b/test/dummy/app/models/person.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Person
   attr_accessor :diaspora_id, :url, :guid, :serialized_public_key, :serialized_private_key
 
diff --git a/test/dummy/config.ru b/test/dummy/config.ru
index 193e5fe..097cb7b 100644
--- a/test/dummy/config.ru
+++ b/test/dummy/config.ru
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # This file is used by Rack-based servers to start the application.
 
 require ::File.expand_path("../config/environment", __FILE__)
diff --git a/test/dummy/config/application.rb b/test/dummy/config/application.rb
index 7b71468..9ad1bef 100644
--- a/test/dummy/config/application.rb
+++ b/test/dummy/config/application.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "boot"
 
 require "action_controller/railtie"
diff --git a/test/dummy/config/boot.rb b/test/dummy/config/boot.rb
index bb5714c..55bd95c 100644
--- a/test/dummy/config/boot.rb
+++ b/test/dummy/config/boot.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Set up gems listed in the Gemfile.
 ENV["BUNDLE_GEMFILE"] ||= File.expand_path("../../../Gemfile", __dir__)
 require "bundler/setup" if File.exist?(ENV["BUNDLE_GEMFILE"])
diff --git a/test/dummy/config/environment.rb b/test/dummy/config/environment.rb
index f970ac2..15b0f91 100644
--- a/test/dummy/config/environment.rb
+++ b/test/dummy/config/environment.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Load the rails application
 require_relative "application"
 
diff --git a/test/dummy/config/environments/development.rb b/test/dummy/config/environments/development.rb
index 2d78bb2..1b163c3 100644
--- a/test/dummy/config/environments/development.rb
+++ b/test/dummy/config/environments/development.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 Rails.application.configure do
   # Settings specified here will take precedence over those in config/application.rb.
 
diff --git a/test/dummy/config/environments/production.rb b/test/dummy/config/environments/production.rb
index da40eee..65af5f6 100644
--- a/test/dummy/config/environments/production.rb
+++ b/test/dummy/config/environments/production.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 Rails.application.configure do
   # Settings specified here will take precedence over those in config/application.rb.
 
diff --git a/test/dummy/config/environments/test.rb b/test/dummy/config/environments/test.rb
index 6eee539..711ecad 100644
--- a/test/dummy/config/environments/test.rb
+++ b/test/dummy/config/environments/test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 Rails.application.configure do
   # Settings specified here will take precedence over those in config/application.rb.
 
diff --git a/test/dummy/config/initializers/diaspora_federation.rb b/test/dummy/config/initializers/diaspora_federation.rb
index 430b5e8..09eed96 100644
--- a/test/dummy/config/initializers/diaspora_federation.rb
+++ b/test/dummy/config/initializers/diaspora_federation.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "diaspora_federation"
 
 ca_file = if File.file?("/etc/ssl/certs/ca-certificates.crt")
diff --git a/test/dummy/config/initializers/faraday.rb b/test/dummy/config/initializers/faraday.rb
index 027a3fa..856578c 100644
--- a/test/dummy/config/initializers/faraday.rb
+++ b/test/dummy/config/initializers/faraday.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Use net_http in test, that's better supported by webmock
 unless Rails.env.test?
   require "typhoeus/adapters/faraday"
diff --git a/test/dummy/config/initializers/filter_parameter_logging.rb b/test/dummy/config/initializers/filter_parameter_logging.rb
index 4a994e1..7a4f47b 100644
--- a/test/dummy/config/initializers/filter_parameter_logging.rb
+++ b/test/dummy/config/initializers/filter_parameter_logging.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Be sure to restart your server when you modify this file.
 
 # Configure sensitive parameters which will be filtered from the log file.
diff --git a/test/dummy/config/initializers/session_store.rb b/test/dummy/config/initializers/session_store.rb
index 7ee20e3..606745f 100644
--- a/test/dummy/config/initializers/session_store.rb
+++ b/test/dummy/config/initializers/session_store.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Be sure to restart your server when you modify this file.
 
 Rails.application.config.session_store :cookie_store, key: "_dummy_session"
diff --git a/test/dummy/config/initializers/wrap_parameters.rb b/test/dummy/config/initializers/wrap_parameters.rb
index a7b1b91..4755468 100644
--- a/test/dummy/config/initializers/wrap_parameters.rb
+++ b/test/dummy/config/initializers/wrap_parameters.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Be sure to restart your server when you modify this file.
 
 # This file contains settings for ActionController::ParamsWrapper which
diff --git a/test/dummy/config/routes.rb b/test/dummy/config/routes.rb
index 4dccc36..cabecec 100644
--- a/test/dummy/config/routes.rb
+++ b/test/dummy/config/routes.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 Rails.application.routes.draw do
   mount DiasporaFederation::Engine => "/"