diff --git a/.rubocop.yml b/.rubocop.yml
index ab7c618..ae0bde2 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -1,78 +1,37 @@
-require: rubocop-rspec
+# The behavior of RuboCop can be controlled via the .rubocop.yml
+# configuration file. It makes it possible to enable/disable
+# certain cops (checks) and to alter their behavior if they accept
+# any parameters. The file can be placed either in your home
+# directory or in some project directory.
+#
+# RuboCop will start looking for the configuration file in the directory
+# where the inspected file is and continue its way up to the root directory.
+#
+# See https://docs.rubocop.org/rubocop/configuration
+require:
+  - rubocop-rspec
 
-Gemspec/DateAssignment: # (new in 1.10)
-  Enabled: true
-Layout/LineEndStringConcatenationIndentation: # (new in 1.18)
-  Enabled: true
-Layout/SpaceBeforeBrackets: # (new in 1.7)
-  Enabled: true
-Lint/AmbiguousAssignment: # (new in 1.7)
-  Enabled: true
-Lint/DeprecatedConstants: # (new in 1.8)
-  Enabled: true
-Lint/DuplicateBranch: # (new in 1.3)
-  Enabled: true
-Lint/DuplicateRegexpCharacterClassElement: # (new in 1.1)
-  Enabled: true
-Lint/EmptyBlock: # (new in 1.1)
-  Enabled: true
-Lint/EmptyClass: # (new in 1.3)
-  Enabled: true
-Lint/EmptyInPattern: # (new in 1.16)
-  Enabled: true
-Lint/LambdaWithoutLiteralBlock: # (new in 1.8)
-  Enabled: true
-Lint/NoReturnInBeginEndBlocks: # (new in 1.2)
-  Enabled: true
-Lint/NumberedParameterAssignment: # (new in 1.9)
-  Enabled: true
-Lint/OrAssignmentToConstant: # (new in 1.9)
-  Enabled: true
-Lint/RedundantDirGlobSort: # (new in 1.8)
-  Enabled: true
-Lint/SymbolConversion: # (new in 1.9)
-  Enabled: true
-Lint/ToEnumArguments: # (new in 1.1)
-  Enabled: true
-Lint/TripleQuotes: # (new in 1.9)
-  Enabled: true
-Lint/UnexpectedBlockArity: # (new in 1.5)
-  Enabled: true
-Lint/UnmodifiedReduceAccumulator: # (new in 1.1)
-  Enabled: true
-Naming/InclusiveLanguage: # (new in 1.18)
-  Enabled: true
-Style/ArgumentsForwarding: # (new in 1.1)
-  Enabled: true
-Style/CollectionCompact: # (new in 1.2)
-  Enabled: true
-Style/DocumentDynamicEvalDefinition: # (new in 1.1)
-  Enabled: true
-Style/EndlessMethod: # (new in 1.8)
-  Enabled: true
-Style/HashConversion: # (new in 1.10)
-  Enabled: true
-Style/HashExcept: # (new in 1.7)
-  Enabled: true
-Style/IfWithBooleanLiteralBranches: # (new in 1.9)
-  Enabled: true
-Style/InPatternThen: # (new in 1.16)
-  Enabled: true
-Style/MultilineInPatternThen: # (new in 1.16)
-  Enabled: true
-Style/NegatedIfElseCondition: # (new in 1.2)
-  Enabled: true
-Style/NilLambda: # (new in 1.3)
-  Enabled: true
-Style/QuotedSymbols: # (new in 1.16)
-  Enabled: true
-Style/RedundantArgument: # (new in 1.4)
-  Enabled: true
-Style/StringChars: # (new in 1.12)
-  Enabled: true
-Style/SwapValues: # (new in 1.1)
-  Enabled: true
-RSpec/IdenticalEqualityAssertion: # (new in 2.4)
-  Enabled: true
-RSpec/Rails/AvoidSetupHook: # (new in 2.4)
-  Enabled: true
\ No newline at end of file
+AllCops:
+  TargetRubyVersion: 2.7
+  NewCops: enable
+
+Layout/LineLength:
+  Enabled: false
+
+Metrics/BlockLength:
+  Enabled: false
+
+Metrics/ClassLength:
+  Enabled: false
+
+Metrics/MethodLength:
+  Enabled: false
+
+Naming/AccessorMethodName:
+  Enabled: false
+
+RSpec/MultipleMemoizedHelpers:
+  Enabled: false
+
+RSpec/ExampleLength:
+  Enabled: false
\ No newline at end of file
diff --git a/Gemfile.lock b/Gemfile.lock
index ec9dee1..93a95f4 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -62,7 +62,7 @@ GEM
       byebug (~> 11.0)
       pry (>= 0.13, < 0.15)
     rainbow (3.1.1)
-    rb-fsevent (0.11.1)
+    rb-fsevent (0.11.2)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
     regexp_parser (2.5.0)
diff --git a/bin/datadog_backup b/bin/datadog_backup
index f723943..b989b18 100755
--- a/bin/datadog_backup
+++ b/bin/datadog_backup
@@ -11,7 +11,6 @@ LOGGER.level = Logger::INFO
 
 require 'datadog_backup'
 
-
 def fatal(message)
   LOGGER.fatal(message)
   exit 1
@@ -19,10 +18,10 @@ end
 
 def options_valid?(options)
   %w[backup diffs restore].include?(options[:action])
-  %w[DD_API_KEY DD_APP_KEY].all? { |key| ENV[key] }
+  %w[DD_API_KEY DD_APP_KEY].all? { |key| ENV.fetch(key, nil) }
 end
 
-def prereqs(defaults)
+def prereqs(defaults) # rubocop:disable Metrics/AbcSize
   ARGV << '--help' if ARGV.empty?
 
   result = defaults.dup
@@ -49,6 +48,9 @@ def prereqs(defaults)
     opts.on('--dashboards-only') do
       result[:resources] = [DatadogBackup::Dashboards]
     end
+    opts.on('--synthetics-only') do
+      result[:resources] = [DatadogBackup::Synthetics]
+    end
     opts.on(
       '--json',
       'format backups as JSON instead of YAML. Does not impact `diffs` nor `restore`, but do not mix formats in the same backup-dir.'
@@ -78,9 +80,9 @@ defaults = {
   action: nil,
   backup_dir: File.join(ENV.fetch('PWD'), 'backup'),
   diff_format: :color,
-  resources: [DatadogBackup::Dashboards, DatadogBackup::Monitors],
+  resources: [DatadogBackup::Dashboards, DatadogBackup::Monitors, DatadogBackup::Synthetics],
   output_format: :yaml,
   force_restore: false
 }
 
-DatadogBackup::Cli.new(prereqs(defaults)).run!
\ No newline at end of file
+DatadogBackup::Cli.new(prereqs(defaults)).run!
diff --git a/datadog_backup.gemspec b/datadog_backup.gemspec
index cbde451..62f5b36 100644
--- a/datadog_backup.gemspec
+++ b/datadog_backup.gemspec
@@ -19,7 +19,7 @@ Gem::Specification.new do |spec|
   spec.executables   = spec.files.grep(%r{^bin/}) { |f| File.basename(f) }
   spec.require_paths = ['lib']
 
-  spec.required_ruby_version = ['>= 2.7']
+  spec.required_ruby_version = '>= 2.7'
 
   spec.add_dependency 'amazing_print'
   spec.add_dependency 'concurrent-ruby'
@@ -28,11 +28,10 @@ Gem::Specification.new do |spec|
   spec.add_dependency 'faraday'
   spec.add_dependency 'faraday-retry'
 
-
   spec.add_development_dependency 'bundler'
+  spec.add_development_dependency 'guard-rspec'
   spec.add_development_dependency 'pry'
   spec.add_development_dependency 'pry-byebug'
-  spec.add_development_dependency 'guard-rspec'
   spec.add_development_dependency 'rspec'
   spec.add_development_dependency 'rubocop'
   spec.add_development_dependency 'rubocop-rspec'
diff --git a/lib/datadog_backup.rb b/lib/datadog_backup.rb
index c974964..c772b5e 100644
--- a/lib/datadog_backup.rb
+++ b/lib/datadog_backup.rb
@@ -8,12 +8,12 @@
 require_relative 'datadog_backup/core'
 require_relative 'datadog_backup/dashboards'
 require_relative 'datadog_backup/monitors'
+require_relative 'datadog_backup/synthetics'
 require_relative 'datadog_backup/thread_pool'
 require_relative 'datadog_backup/version'
 require_relative 'datadog_backup/deprecations'
 DatadogBackup::Deprecations.check
 
-
+# DatadogBackup is a gem for backing up and restoring Datadog monitors and dashboards.
 module DatadogBackup
 end
-
diff --git a/lib/datadog_backup/cli.rb b/lib/datadog_backup/cli.rb
index f71bcce..d6a041a 100644
--- a/lib/datadog_backup/cli.rb
+++ b/lib/datadog_backup/cli.rb
@@ -4,6 +4,7 @@
 require 'amazing_print'
 
 module DatadogBackup
+  # CLI is the command line interface for the datadog_backup gem.
   class Cli
     include ::DatadogBackup::Options
 
@@ -11,9 +12,9 @@ def all_diff_futures
       LOGGER.info("Starting diffs on #{::DatadogBackup::ThreadPool::TPOOL.max_length} threads")
       any_resource_instance
         .all_file_ids_for_selected_resources
-        .map do |id|
-        Concurrent::Promises.future_on(::DatadogBackup::ThreadPool::TPOOL, id) do |id|
-          [id, getdiff(id)]
+        .map do |file_id|
+        Concurrent::Promises.future_on(::DatadogBackup::ThreadPool::TPOOL, file_id) do |fid|
+          [fid, getdiff(fid)]
         end
       end
     end
@@ -32,32 +33,17 @@ def definitive_resource_instance(id)
       matching_resource_instance(any_resource_instance.class_from_id(id))
     end
 
-    def diffs
-      futures = all_diff_futures
-      ::DatadogBackup::ThreadPool.watcher.join
-
-      format_diff_output(
-        Concurrent::Promises
-          .zip(*futures)
-          .value!
-          .compact
-      )
-    end
-
     def getdiff(id)
       result = definitive_resource_instance(id).diff(id)
       case result
-      when ''
-        nil
-      when "\n"
-        nil
-      when '<div class="diff"></div>'
+      when '---' || '' || "\n" || '<div class="diff"></div>'
         nil
       else
         result
       end
     end
 
+    # rubocop:disable Style/StringConcatenation
     def format_diff_output(diff_output)
       case diff_format
       when nil, :color
@@ -69,58 +55,31 @@ def format_diff_output(diff_output)
           Diffy::CSS +
           '</style></head><body>' +
           diff_output.map do |id, diff|
-            "<br><br> ---<br><strong> id: #{id}</strong><br>" + diff
+            "<br><br> ---<br><strong> id: #{id}</strong><br>#{diff}"
           end.join('<br>') +
           '</body></html>'
       else
         raise 'Unexpected diff_format.'
       end
     end
+    # rubocop:enable Style/StringConcatenation
 
     def initialize(options)
       @options = options
     end
 
-    def matching_resource_instance(klass)
-      resource_instances.select { |resource_instance| resource_instance.instance_of?(klass) }.first
-    end
-
-    def resource_instances
-      @resource_instances ||= resources.map do |resource|
-        resource.new(@options)
-      end
-    end
-
     def restore
       futures = all_diff_futures
       watcher = ::DatadogBackup::ThreadPool.watcher
 
       futures.each do |future|
         id, diff = *future.value!
-        next unless diff
+        next if diff.nil? || diff.empty?
 
         if @options[:force_restore]
           definitive_resource_instance(id).restore(id)
         else
-          puts '--------------------------------------------------------------------------------'
-          puts format_diff_output([id, diff])
-          puts '(r)estore to Datadog, overwrite local changes and (d)ownload, (s)kip, or (q)uit?'
-          response = $stdin.gets.chomp
-          case response
-          when 'q'
-            exit
-          when 'r'
-            puts "Restoring #{id} to Datadog."
-            definitive_resource_instance(id).restore(id)
-          when 'd'
-            puts "Downloading #{id} from Datadog."
-            definitive_resource_instance(id).get_and_write_file(id)
-          when 's'
-            next
-          else
-            puts 'Invalid response, please try again.'
-            response = $stdin.gets.chomp
-          end
+          ask_to_restore(id, diff)
         end
       end
       watcher.join if watcher.status
@@ -131,5 +90,42 @@ def run!
     rescue SystemExit, Interrupt
       ::DatadogBackup::ThreadPool.shutdown
     end
+
+    private
+
+    def ask_to_restore(id, diff)
+      puts '--------------------------------------------------------------------------------'
+      puts format_diff_output([id, diff])
+      puts '(r)estore to Datadog, overwrite local changes and (d)ownload, (s)kip, or (q)uit?'
+      loop do
+        response = $stdin.gets.chomp
+        case response
+        when 'q'
+          exit
+        when 'r'
+          puts "Restoring #{id} to Datadog."
+          definitive_resource_instance(id).restore(id)
+          break
+        when 'd'
+          puts "Downloading #{id} from Datadog."
+          definitive_resource_instance(id).get_and_write_file(id)
+          break
+        when 's'
+          break
+        else
+          puts 'Invalid response, please try again.'
+        end
+      end
+    end
+
+    def matching_resource_instance(klass)
+      resource_instances.select { |resource_instance| resource_instance.instance_of?(klass) }.first
+    end
+
+    def resource_instances
+      @resource_instances ||= resources.map do |resource|
+        resource.new(@options)
+      end
+    end
   end
 end
diff --git a/lib/datadog_backup/core.rb b/lib/datadog_backup/core.rb
index 552173c..f5bf7ad 100644
--- a/lib/datadog_backup/core.rb
+++ b/lib/datadog_backup/core.rb
@@ -5,14 +5,14 @@
 require 'faraday'
 require 'faraday/retry'
 
-
-
 module DatadogBackup
+  # The default options for backing up and restores.
+  # This base class is meant to be extended by specific resources, such as Dashboards, Monitors, and so on.
   class Core
     include ::DatadogBackup::LocalFilesystem
     include ::DatadogBackup::Options
 
-    @@retry_options = {
+    @retry_options = {
       max: 5,
       interval: 0.05,
       interval_randomness: 0.5,
@@ -20,27 +20,27 @@ class Core
     }
 
     def api_service
-      conn ||= Faraday.new(
-          url: api_url,
-          headers: {
-            'DD-API-KEY' => ENV.fetch('DD_API_KEY'),
-            'DD-APPLICATION-KEY' => ENV.fetch('DD_APP_KEY')
-          }
-        ) do |faraday|
-            faraday.request :json
-            faraday.request :retry, @@retry_options
-            faraday.response(:logger, LOGGER, {headers: true, bodies: LOGGER.debug?, log_level: :debug}) do | logger |
-              logger.filter(/(DD-API-KEY:)([^&]+)/, '\1[REDACTED]')
-              logger.filter(/(DD-APPLICATION-KEY:)([^&]+)/, '\1[REDACTED]')
-            end
-            faraday.response :raise_error
-            faraday.response :json
-            faraday.adapter Faraday.default_adapter
-          end
+      @api_service ||= Faraday.new(
+        url: api_url,
+        headers: {
+          'DD-API-KEY' => ENV.fetch('DD_API_KEY'),
+          'DD-APPLICATION-KEY' => ENV.fetch('DD_APP_KEY')
+        }
+      ) do |faraday|
+        faraday.request :json
+        faraday.request :retry, @retry_options
+        faraday.response(:logger, LOGGER, { headers: true, bodies: LOGGER.debug?, log_level: :debug }) do |logger|
+          logger.filter(/(DD-API-KEY:)([^&]+)/, '\1[REDACTED]')
+          logger.filter(/(DD-APPLICATION-KEY:)([^&]+)/, '\1[REDACTED]')
+        end
+        faraday.response :raise_error
+        faraday.response :json
+        faraday.adapter Faraday.default_adapter
+      end
     end
 
     def api_url
-      ENV.fetch('DD_SITE_URL', "https://api.datadoghq.com/")
+      ENV.fetch('DD_SITE_URL', 'https://api.datadoghq.com/')
     end
 
     def api_version
@@ -51,6 +51,11 @@ def api_resource_name
       raise 'subclass is expected to implement #api_resource_name'
     end
 
+    # Some resources have a different key for the id.
+    def id_keyname
+      'id'
+    end
+
     def backup
       raise 'subclass is expected to implement #backup'
     end
@@ -61,8 +66,8 @@ def diff(id)
       current = except(get_by_id(id)).deep_sort.to_yaml
       filesystem = except(load_from_file_by_id(id)).deep_sort.to_yaml
       result = ::Diffy::Diff.new(current, filesystem, include_plus_and_minus_in_html: true).to_s(diff_format)
-      LOGGER.debug("Compared ID #{id} and found #{result}")
-      result
+      LOGGER.debug("Compared ID #{id} and found filesystem: #{filesystem} <=> current: #{current} == result: #{result}")
+      result.chomp
     end
 
     # Returns a hash with banlist elements removed
@@ -74,6 +79,7 @@ def except(hash)
       end
     end
 
+    # Fetch the specified resource from Datadog
     def get(id)
       params = {}
       headers = {}
@@ -81,18 +87,25 @@ def get(id)
       body_with_2xx(response)
     end
 
+    # Returns a list of all resources in Datadog
+    # Do not use directly, but use the child classes' #all method instead
     def get_all
       return @get_all if @get_all
+
       params = {}
       headers = {}
       response = api_service.get("/api/#{api_version}/#{api_resource_name}", params, headers)
       @get_all = body_with_2xx(response)
     end
 
+    # Download the resource from Datadog and write it to a file
     def get_and_write_file(id)
-      write_file(dump(get_by_id(id)), filename(id))
+      body = get_by_id(id)
+      write_file(dump(body), filename(id))
+      body
     end
 
+    # Fetch the specified resource from Datadog and remove the banlist elements
     def get_by_id(id)
       except(get(id))
     end
@@ -107,43 +120,57 @@ def myclass
       self.class.to_s.split(':').last.downcase
     end
 
-    # Calls out to Datadog and checks for a '200' response
+    # Create a new resource in Datadog
     def create(body)
       headers = {}
-      response =  api_service.post("/api/#{api_version}/#{api_resource_name}", body, headers)
+      response = api_service.post("/api/#{api_version}/#{api_resource_name}", body, headers)
       body = body_with_2xx(response)
-      LOGGER.warn "Successfully created #{body.fetch('id')} in datadog."
+      LOGGER.warn "Successfully created #{body.fetch(id_keyname)} in datadog."
+      LOGGER.info 'Invalidating cache'
+      @get_all = nil
       body
     end
 
-    # Calls out to Datadog and checks for a '200' response
+    # Update an existing resource in Datadog
     def update(id, body)
       headers = {}
       response = api_service.put("/api/#{api_version}/#{api_resource_name}/#{id}", body, headers)
       body = body_with_2xx(response)
-      LOGGER.warn 'Successfully restored #{id} to datadog.'
+      LOGGER.warn "Successfully restored #{id} to datadog."
+      LOGGER.info 'Invalidating cache'
+      @get_all = nil
       body
     end
 
+    # If the resource exists in Datadog, update it. Otherwise, create it.
     def restore(id)
       body = load_from_file_by_id(id)
       begin
         update(id, body)
       rescue RuntimeError => e
-        if e.message.include?('update failed with error 404')
-          new_id = create(body).fetch('id')
+        raise e.message unless e.message.include?('update failed with error 404')
 
-          FileUtils.rm(find_file_by_id(id))
-          get_and_write_file(new_id)
-        else
-          raise e.message
-        end
+        create_newly(id, body)
       end
     end
 
+    # Return the Faraday body from a response with a 2xx status code, otherwise raise an error
     def body_with_2xx(response)
-      raise "#{caller_locations(1,1)[0].label} failed with error #{response.status}" unless response.status.to_s =~ /^2/
+      unless response.status.to_s =~ /^2/
+        raise "#{caller_locations(1,
+                                  1)[0].label} failed with error #{response.status}"
+      end
+
       response.body
     end
+
+    private
+
+    # Create a new resource in Datadog, then move the old file to the new resource's ID
+    def create_newly(file_id, body)
+      new_id = create(body).fetch(id_keyname)
+      FileUtils.rm(find_file_by_id(file_id))
+      get_and_write_file(new_id)
+    end
   end
 end
diff --git a/lib/datadog_backup/dashboards.rb b/lib/datadog_backup/dashboards.rb
index 889d73d..9c44f0a 100644
--- a/lib/datadog_backup/dashboards.rb
+++ b/lib/datadog_backup/dashboards.rb
@@ -1,7 +1,11 @@
 # frozen_string_literal: true
 
 module DatadogBackup
+  # Dashboards specific overrides for backup and restore.
   class Dashboards < Core
+    def all
+      get_all.fetch('dashboards')
+    end
 
     def api_version
       'v1'
@@ -11,13 +15,15 @@ def api_resource_name
       'dashboard'
     end
 
+    def id_keyname
+      'id'
+    end
+
     def backup
       LOGGER.info("Starting diffs on #{::DatadogBackup::ThreadPool::TPOOL.max_length} threads")
-
-      dashboards = get_all.fetch('dashboards')
-      futures = dashboards.map do |board|
-        Concurrent::Promises.future_on(::DatadogBackup::ThreadPool::TPOOL, board) do |board|
-          id = board['id']
+      futures = all.map do |dashboard|
+        Concurrent::Promises.future_on(::DatadogBackup::ThreadPool::TPOOL, dashboard) do |board|
+          id = board[id_keyname]
           get_and_write_file(id)
         end
       end
diff --git a/lib/datadog_backup/deprecations.rb b/lib/datadog_backup/deprecations.rb
index 09c4074..4a431cb 100644
--- a/lib/datadog_backup/deprecations.rb
+++ b/lib/datadog_backup/deprecations.rb
@@ -1,11 +1,10 @@
-
+# frozen_string_literal: true
 
 module DatadogBackup
+  # Notify the user if they are using deprecated features.
   module Deprecations
     def self.check
-      if RUBY_VERSION < '2.7'
-        LOGGER.warn "ruby-#{RUBY_VERSION} is deprecated. Ruby 2.7 or higher will be required to use this gem after datadog_backup@v3"
-      end
+      LOGGER.warn "ruby-#{RUBY_VERSION} is deprecated. Ruby 2.7 or higher will be required to use this gem after datadog_backup@v3" if RUBY_VERSION < '2.7'
     end
   end
-end
\ No newline at end of file
+end
diff --git a/lib/datadog_backup/local_filesystem.rb b/lib/datadog_backup/local_filesystem.rb
index 3a6d674..df3f30d 100644
--- a/lib/datadog_backup/local_filesystem.rb
+++ b/lib/datadog_backup/local_filesystem.rb
@@ -6,11 +6,10 @@
 require 'deepsort'
 
 module DatadogBackup
+  ##
+  # Meant to be mixed into DatadogBackup::Core
+  # Relies on @options[:backup_dir] and @options[:output_format]
   module LocalFilesystem
-    ##
-    # Meant to be mixed into DatadogBackup::Core
-    # Relies on @options[:backup_dir] and @options[:output_format]
-
     def all_files
       ::Dir.glob(::File.join(backup_dir, '**', '*')).select { |f| ::File.file?(f) }
     end
@@ -46,7 +45,7 @@ def filename(id)
     end
 
     def file_type(filepath)
-      ::File.extname(filepath).strip.downcase[1..-1].to_sym
+      ::File.extname(filepath).strip.downcase[1..].to_sym
     end
 
     def find_file_by_id(id)
diff --git a/lib/datadog_backup/monitors.rb b/lib/datadog_backup/monitors.rb
index 3ecae48..a35dcba 100644
--- a/lib/datadog_backup/monitors.rb
+++ b/lib/datadog_backup/monitors.rb
@@ -1,7 +1,11 @@
 # frozen_string_literal: true
 
 module DatadogBackup
+  # Monitor specific overrides for backup and restore.
   class Monitors < Core
+    def all
+      get_all
+    end
 
     def api_version
       'v1'
@@ -12,14 +16,14 @@ def api_resource_name
     end
 
     def backup
-      get_all.map do |monitor|
+      all.map do |monitor|
         id = monitor['id']
         write_file(dump(get_by_id(id)), filename(id))
       end
     end
 
     def get_by_id(id)
-      monitor = get_all.select { |monitor| monitor['id'].to_s == id.to_s }.first
+      monitor = all.select { |m| m['id'].to_s == id.to_s }.first
       monitor.nil? ? {} : except(monitor)
     end
 
diff --git a/lib/datadog_backup/options.rb b/lib/datadog_backup/options.rb
index b769a51..6280da2 100644
--- a/lib/datadog_backup/options.rb
+++ b/lib/datadog_backup/options.rb
@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 module DatadogBackup
+  # Describes what the user wants to see done.
   module Options
     def action
       @options[:action]
diff --git a/lib/datadog_backup/synthetics.rb b/lib/datadog_backup/synthetics.rb
new file mode 100644
index 0000000..957a806
--- /dev/null
+++ b/lib/datadog_backup/synthetics.rb
@@ -0,0 +1,66 @@
+# frozen_string_literal: true
+
+module DatadogBackup
+  # Synthetic specific overrides for backup and restore.
+  class Synthetics < Core
+    def all
+      get_all.fetch('tests')
+    end
+
+    def api_version
+      'v1'
+    end
+
+    def api_resource_name(body = nil)
+      return 'synthetics/tests' if body.nil?
+      return 'synthetics/tests' if body['type'].nil?
+      return 'synthetics/tests/browser' if body['type'].to_s == 'browser'
+      return 'synthetics/tests/api' if body['type'].to_s == 'api'
+
+      raise "Unknown type #{body['type']}"
+    end
+
+    def id_keyname
+      'public_id'
+    end
+
+    def backup
+      all.map do |synthetic|
+        id = synthetic[id_keyname]
+        get_and_write_file(id)
+      end
+    end
+
+    def get_by_id(id)
+      synthetic = all.select { |s| s[id_keyname].to_s == id.to_s }.first
+      synthetic.nil? ? {} : except(synthetic)
+    end
+
+    def initialize(options)
+      super(options)
+      @banlist = %w[creator created_at modified_at monitor_id public_id].freeze
+    end
+
+    def create(body)
+      create_api_resource_name = api_resource_name(body)
+      headers = {}
+      response = api_service.post("/api/#{api_version}/#{create_api_resource_name}", body, headers)
+      resbody = body_with_2xx(response)
+      LOGGER.warn "Successfully created #{resbody.fetch(id_keyname)} in datadog."
+      LOGGER.info 'Invalidating cache'
+      @get_all = nil
+      resbody
+    end
+
+    def update(id, body)
+      update_api_resource_name = api_resource_name(body)
+      headers = {}
+      response = api_service.put("/api/#{api_version}/#{update_api_resource_name}/#{id}", body, headers)
+      resbody = body_with_2xx(response)
+      LOGGER.warn "Successfully restored #{id} to datadog."
+      LOGGER.info 'Invalidating cache'
+      @get_all = nil
+      resbody
+    end
+  end
+end
diff --git a/lib/datadog_backup/thread_pool.rb b/lib/datadog_backup/thread_pool.rb
index 1a4228b..6d607d8 100644
--- a/lib/datadog_backup/thread_pool.rb
+++ b/lib/datadog_backup/thread_pool.rb
@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 module DatadogBackup
+  # Used by CLI and Dashboards to size thread pool according to available CPU cores.
   module ThreadPool
     TPOOL = ::Concurrent::ThreadPoolExecutor.new(
       min_threads: [2, Concurrent.processor_count].max,
diff --git a/spec/datadog_backup/cli_spec.rb b/spec/datadog_backup/cli_spec.rb
index 70044ac..5d7590e 100644
--- a/spec/datadog_backup/cli_spec.rb
+++ b/spec/datadog_backup/cli_spec.rb
@@ -47,8 +47,8 @@
         dashboards.write_file('{"text": "diff"}', "#{tempdir}/dashboards/deleted.json")
 
         stubs.get('/api/v1/dashboard') { all_dashboards }
-        stubs.get('/api/v1/dashboard/stillthere') {[200, {}, {}]}
-        stubs.get('/api/v1/dashboard/alsostillthere') {[200, {}, {}]}
+        stubs.get('/api/v1/dashboard/stillthere') { respond_with200({}) }
+        stubs.get('/api/v1/dashboard/alsostillthere') { respond_with200({}) }
       end
 
       it 'deletes the file locally as well' do
@@ -58,66 +58,81 @@
     end
   end
 
-  describe '#diffs' do
-    subject { cli.diffs }
-
-    before do
-      dashboards.write_file('{"text": "diff"}', "#{tempdir}/dashboards/diffs1.json")
-      dashboards.write_file('{"text": "diff"}', "#{tempdir}/dashboards/diffs2.json")
-      dashboards.write_file('{"text": "diff"}', "#{tempdir}/dashboards/diffs3.json")
-      allow(dashboards).to receive(:get_by_id).and_return({ 'text' => 'diff2' })
-    end
-
-    it {
-      expect(subject).to include(
-        " ---\n id: diffs1\n ---\n-text: diff2\n+text: diff\n",
-        " ---\n id: diffs3\n ---\n-text: diff2\n+text: diff\n",
-        " ---\n id: diffs2\n ---\n-text: diff2\n+text: diff\n"
-      )
-    }
-  end
-
   describe '#restore' do
-    subject { cli.restore }
+    subject(:restore) { cli.restore }
 
     before do
       dashboards.write_file('{"text": "diff"}', "#{tempdir}/dashboards/diffs1.json")
       allow(dashboards).to receive(:get_by_id).and_return({ 'text' => 'diff2' })
+      allow(dashboards).to receive(:write_file)
+      allow(dashboards).to receive(:update)
     end
 
     example 'starts interactive restore' do
       allow($stdin).to receive(:gets).and_return('q')
 
-      expect { subject }.to(
+      expect { restore }.to(
         output(/\(r\)estore to Datadog, overwrite local changes and \(d\)ownload, \(s\)kip, or \(q\)uit\?/).to_stdout
         .and(raise_error(SystemExit))
       )
     end
 
-    example 'restore' do
-      allow($stdin).to receive(:gets).and_return('r')
-      expect(dashboards).to receive(:update).with('diffs1', { 'text' => 'diff' })
-      subject
+    context 'when the user chooses to restore' do
+      before do
+        allow($stdin).to receive(:gets).and_return('r')
+      end
+
+      example 'it restores from disk to server' do
+        restore
+        expect(dashboards).to have_received(:update).with('diffs1', { 'text' => 'diff' })
+      end
     end
 
-    example 'download' do
-      allow($stdin).to receive(:gets).and_return('d')
-      expect(dashboards).to receive(:write_file).with(%({\n  "text": "diff2"\n}), "#{tempdir}/dashboards/diffs1.json")
-      subject
+    context 'when the user chooses to download' do
+      before do
+        allow($stdin).to receive(:gets).and_return('d')
+      end
+
+      example 'it writes from server to disk' do
+        restore
+        expect(dashboards).to have_received(:write_file).with(%({\n  "text": "diff2"\n}), "#{tempdir}/dashboards/diffs1.json")
+      end
     end
 
-    example 'skip' do
-      allow($stdin).to receive(:gets).and_return('s')
-      expect(dashboards).not_to receive(:write_file)
-      expect(dashboards).not_to receive(:update)
-      subject
+    context 'when the user chooses to skip' do
+      before do
+        allow($stdin).to receive(:gets).and_return('s')
+      end
+
+      example 'it does not write to disk' do
+        restore
+        expect(dashboards).not_to have_received(:write_file)
+      end
+
+      example 'it does not update the server' do
+        restore
+        expect(dashboards).not_to have_received(:update)
+      end
     end
 
-    example 'quit' do
-      allow($stdin).to receive(:gets).and_return('q')
-      expect(dashboards).not_to receive(:write_file)
-      expect(dashboards).not_to receive(:update)
-      expect { subject }.to raise_error(SystemExit)
+    context 'when the user chooses to quit' do
+      before do
+        allow($stdin).to receive(:gets).and_return('q')
+      end
+
+      example 'it exits' do
+        expect { restore }.to raise_error(SystemExit)
+      end
+
+      example 'it does not write to disk' do
+        restore
+        expect(dashboards).not_to have_received(:write_file)
+      end
+
+      example 'it does not update the server' do
+        restore
+        expect(dashboards).not_to have_received(:update)
+      end
     end
   end
 end
diff --git a/spec/datadog_backup/core_spec.rb b/spec/datadog_backup/core_spec.rb
index 947f228..5367ad6 100644
--- a/spec/datadog_backup/core_spec.rb
+++ b/spec/datadog_backup/core_spec.rb
@@ -18,11 +18,8 @@
     return core
   end
 
-
-
-
   describe '#diff' do
-    subject { core.diff('diff') }
+    subject(:diff) { core.diff('diff') }
 
     before do
       allow(core).to receive(:get_by_id).and_return({ 'text' => 'diff1', 'extra' => 'diff1' })
@@ -30,13 +27,14 @@
     end
 
     it {
-      expect(subject).to eq <<~EOF
+      expect(diff).to eq(<<~EODIFF
          ---
         -extra: diff1
         -text: diff1
         +extra: diff2
         +text: diff2
-      EOF
+      EODIFF
+      .chomp)
     }
   end
 
@@ -47,11 +45,13 @@
   end
 
   describe '#initialize' do
-    subject { core }
+    subject(:mycore) { core }
 
     it 'makes the subdirectories' do
-      expect(FileUtils).to receive(:mkdir_p).with("#{tempdir}/core")
-      subject
+      fileutils = class_double(FileUtils).as_stubbed_const
+      allow(fileutils).to receive(:mkdir_p)
+      mycore
+      expect(fileutils).to have_received(:mkdir_p).with("#{tempdir}/core")
     end
   end
 
@@ -62,25 +62,25 @@
   end
 
   describe '#create' do
-    subject { core.create({ 'a' => 'b' }) }
+    subject(:create) { core.create({ 'a' => 'b' }) }
 
     example 'it will post /api/v1/dashboard' do
       allow(core).to receive(:api_version).and_return('v1')
       allow(core).to receive(:api_resource_name).and_return('dashboard')
-      stubs.post('/api/v1/dashboard', {'a' => 'b'}) {[200, {},  {'id' => 'whatever-id-abc' }]}
-      subject
+      stubs.post('/api/v1/dashboard', { 'a' => 'b' }) {  respond_with200({ 'id' => 'whatever-id-abc' }) }
+      create
       stubs.verify_stubbed_calls
     end
   end
 
   describe '#update' do
-    subject { core.update('abc-123-def', { 'a' => 'b' }) }
+    subject(:update) { core.update('abc-123-def', { 'a' => 'b' }) }
 
     example 'it puts /api/v1/dashboard' do
       allow(core).to receive(:api_version).and_return('v1')
       allow(core).to receive(:api_resource_name).and_return('dashboard')
-      stubs.put('/api/v1/dashboard/abc-123-def', {'a' => 'b'}) {[200, {},  {'id' => 'whatever-id-abc' }]}
-      subject
+      stubs.put('/api/v1/dashboard/abc-123-def', { 'a' => 'b' }) { respond_with200({ 'id' => 'whatever-id-abc' }) }
+      update
       stubs.verify_stubbed_calls
     end
 
@@ -88,10 +88,11 @@
       before do
         allow(core).to receive(:api_version).and_return('v1')
         allow(core).to receive(:api_resource_name).and_return('dashboard')
-        stubs.put('/api/v1/dashboard/abc-123-def', {'a' => 'b'}) {[404, {},  {'id' => 'whatever-id-abc' }]}
+        stubs.put('/api/v1/dashboard/abc-123-def', { 'a' => 'b' }) { [404, {}, { 'id' => 'whatever-id-abc' }] }
       end
+
       it 'raises an error' do
-        expect { subject }.to raise_error(RuntimeError, 'update failed with error 404')
+        expect { update }.to raise_error(RuntimeError, 'update failed with error 404')
       end
     end
   end
@@ -100,35 +101,55 @@
     before do
       allow(core).to receive(:api_version).and_return('api-version-string')
       allow(core).to receive(:api_resource_name).and_return('api-resource-name-string')
-      stubs.get('/api/api-version-string/api-resource-name-string/abc-123-def') {[200, {},  {'test'  => 'ok' }]}
-      stubs.get('/api/api-version-string/api-resource-name-string/bad-123-id') {[404, {},  {'error'  => 'blahblah_not_found' }]}
+      stubs.get('/api/api-version-string/api-resource-name-string/abc-123-def') { respond_with200({ 'test' => 'ok' }) }
+      stubs.get('/api/api-version-string/api-resource-name-string/bad-123-id') do
+        [404, {}, { 'error' => 'blahblah_not_found' }]
+      end
       allow(core).to receive(:load_from_file_by_id).and_return({ 'load' => 'ok' })
     end
 
     context 'when id exists' do
-      subject { core.restore('abc-123-def') }
+      subject(:restore) { core.restore('abc-123-def') }
 
       example 'it calls out to update' do
-        expect(core).to receive(:update).with('abc-123-def', { 'load' => 'ok' })
-        subject
+        allow(core).to receive(:update)
+        restore
+        expect(core).to have_received(:update).with('abc-123-def', { 'load' => 'ok' })
       end
     end
 
     context 'when id does not exist on remote' do
-      subject { core.restore('bad-123-id') }
+      subject(:restore_newly) { core.restore('bad-123-id') }
+
+      let(:fileutils) { class_double(FileUtils).as_stubbed_const }
 
       before do
         allow(core).to receive(:load_from_file_by_id).and_return({ 'load' => 'ok' })
-        stubs.put('/api/api-version-string/api-resource-name-string/bad-123-id') {[404, {},  {'error'  => 'id not found' }]}
-        stubs.post('/api/api-version-string/api-resource-name-string', {'load' => 'ok'}) {[200, {},  {'id' => 'my-new-id' }]}
+        stubs.put('/api/api-version-string/api-resource-name-string/bad-123-id') do
+          [404, {}, { 'error' => 'id not found' }]
+        end
+        stubs.post('/api/api-version-string/api-resource-name-string', { 'load' => 'ok' }) do
+          respond_with200({ 'id' => 'my-new-id' })
+        end
+        allow(fileutils).to receive(:rm)
+        allow(core).to receive(:create).with({ 'load' => 'ok' }).and_return({ 'id' => 'my-new-id' })
+        allow(core).to receive(:get_and_write_file)
+        allow(core).to receive(:find_file_by_id).with('bad-123-id').and_return('/path/to/bad-123-id.json')
       end
 
-      example 'it calls out to create then saves the new file and deletes the new file' do
-        expect(core).to receive(:create).with({ 'load' => 'ok' }).and_return({ 'id' => 'my-new-id' })
-        expect(core).to receive(:get_and_write_file).with('my-new-id')
-        allow(core).to receive(:find_file_by_id).with('bad-123-id').and_return('/path/to/bad-123-id.json')
-        expect(FileUtils).to receive(:rm).with('/path/to/bad-123-id.json')
-        subject
+      example 'it calls out to create' do
+        restore_newly
+        expect(core).to have_received(:create).with({ 'load' => 'ok' })
+      end
+
+      example 'it saves the new file' do
+        restore_newly
+        expect(core).to have_received(:get_and_write_file).with('my-new-id')
+      end
+
+      example 'it deletes the old file' do
+        restore_newly
+        expect(fileutils).to have_received(:rm).with('/path/to/bad-123-id.json')
       end
     end
   end
diff --git a/spec/datadog_backup/dashboards_spec.rb b/spec/datadog_backup/dashboards_spec.rb
index b8356c0..8a8fe5d 100644
--- a/spec/datadog_backup/dashboards_spec.rb
+++ b/spec/datadog_backup/dashboards_spec.rb
@@ -23,24 +23,6 @@
       'title' => 'foo'
     }
   end
-  let(:all_dashboards) do
-    [
-      200,
-      {},
-      {
-        'dashboards' => [
-          dashboard_description
-        ]
-      }
-    ]
-  end
-  let(:example_dashboard) do
-    [
-      200,
-      {},
-      board_abc_123_def
-    ]
-  end
   let(:board_abc_123_def) do
     {
       'graphs' => [
@@ -61,6 +43,8 @@
       'title' => 'example dashboard'
     }
   end
+  let(:all_dashboards) { respond_with200({ 'dashboards' => [dashboard_description] }) }
+  let(:example_dashboard) { respond_with200(board_abc_123_def) }
 
   before do
     stubs.get('/api/v1/dashboard') { all_dashboards }
@@ -71,20 +55,32 @@
     subject { dashboards.backup }
 
     it 'is expected to create a file' do
-      file = double('file')
+      file = instance_double(File)
       allow(File).to receive(:open).with(dashboards.filename('abc-123-def'), 'w').and_return(file)
-      expect(file).to receive(:write).with(::JSON.pretty_generate(board_abc_123_def.deep_sort))
+      allow(file).to receive(:write)
       allow(file).to receive(:close)
 
       dashboards.backup
+      expect(file).to have_received(:write).with(::JSON.pretty_generate(board_abc_123_def.deep_sort))
     end
   end
 
+  describe '#filename' do
+    subject { dashboards.filename('abc-123-def') }
+
+    it { is_expected.to eq("#{tempdir}/dashboards/abc-123-def.json") }
+  end
+
+  describe '#get_by_id' do
+    subject { dashboards.get_by_id('abc-123-def') }
+
+    it { is_expected.to eq board_abc_123_def }
+  end
 
   describe '#diff' do
     it 'calls the api only once' do
       dashboards.write_file('{"a":"b"}', dashboards.filename('abc-123-def'))
-      expect(dashboards.diff('abc-123-def')).to eq(<<~EOF
+      expect(dashboards.diff('abc-123-def')).to eq(<<~EODASH
          ---
         -description: example dashboard
         -graphs:
@@ -96,8 +92,8 @@
         -  title: example graph
         -title: example dashboard
         +a: b
-      EOF
-                                                  )
+      EODASH
+      .chomp)
     end
   end
 
@@ -106,10 +102,4 @@
 
     it { is_expected.to eq({ a: :b }) }
   end
-
-  describe '#get_by_id' do
-    subject { dashboards.get_by_id('abc-123-def') }
-
-    it { is_expected.to eq board_abc_123_def }
-  end
 end
diff --git a/spec/datadog_backup/deprecations_spec.rb b/spec/datadog_backup/deprecations_spec.rb
index d080c75..b08e030 100644
--- a/spec/datadog_backup/deprecations_spec.rb
+++ b/spec/datadog_backup/deprecations_spec.rb
@@ -3,7 +3,9 @@
 require 'spec_helper'
 
 describe DatadogBackup::Deprecations do
-  let(:logger) { double }
+  subject(:check) { described_class.check }
+
+  let(:logger) { instance_double(Logger) }
 
   before do
     stub_const('LOGGER', logger)
@@ -12,24 +14,20 @@
 
   %w[2.4.10 2.5.9 2.6.8].each do |ruby_version|
     describe "#check#{ruby_version}" do
-      subject { described_class.check }
-
       it 'does warn' do
         stub_const('RUBY_VERSION', ruby_version)
-        expect(logger).to receive(:warn).with(/ruby-#{ruby_version} is deprecated./)
-        subject
+        check
+        expect(logger).to have_received(:warn).with(/ruby-#{ruby_version} is deprecated./)
       end
     end
   end
 
   %w[2.7.4 3.0.4 3.1.2 3.2.0-preview1].each do |ruby_version|
     describe "#check#{ruby_version}" do
-      subject { described_class.check }
-
       it 'does not warn' do
         stub_const('RUBY_VERSION', ruby_version)
-        expect(logger).to_not receive(:warn).with(/ruby-#{ruby_version} is deprecated./)
-        subject
+        check
+        expect(logger).not_to have_received(:warn).with(/ruby-#{ruby_version} is deprecated./)
       end
     end
   end
diff --git a/spec/datadog_backup/local_filesystem_spec.rb b/spec/datadog_backup/local_filesystem_spec.rb
index 2e93254..727de3e 100644
--- a/spec/datadog_backup/local_filesystem_spec.rb
+++ b/spec/datadog_backup/local_filesystem_spec.rb
@@ -68,13 +68,13 @@
   end
 
   describe '#dump' do
-    context ':json' do
+    context 'when mode is :json' do
       subject { core.dump({ a: :b }) }
 
       it { is_expected.to eq(%({\n  "a": "b"\n})) }
     end
 
-    context ':yaml' do
+    context 'when mode is :yaml' do
       subject { core_yaml.dump({ 'a' => 'b' }) }
 
       it { is_expected.to eq(%(---\na: b\n)) }
@@ -82,13 +82,13 @@
   end
 
   describe '#filename' do
-    context ':json' do
+    context 'when mode is :json' do
       subject { core.filename('abc-123-def') }
 
       it { is_expected.to eq("#{tempdir}/core/abc-123-def.json") }
     end
 
-    context ':yaml' do
+    context 'when mode is :yaml' do
       subject { core_yaml.filename('abc-123-def') }
 
       it { is_expected.to eq("#{tempdir}/core/abc-123-def.yaml") }
@@ -124,13 +124,13 @@
   end
 
   describe '#load_from_file' do
-    context ':json' do
+    context 'when mode is :json' do
       subject { core.load_from_file(%({\n  "a": "b"\n}), :json) }
 
       it { is_expected.to eq('a' => 'b') }
     end
 
-    context ':yaml' do
+    context 'when mode is :yaml' do
       subject { core.load_from_file(%(---\na: b\n), :yaml) }
 
       it { is_expected.to eq('a' => 'b') }
@@ -138,7 +138,7 @@
   end
 
   describe '#load_from_file_by_id' do
-    context 'written in json read in yaml mode' do
+    context 'when the backup is in json but the mode is :yaml' do
       subject { core_yaml.load_from_file_by_id('abc-123-def') }
 
       before { core.write_file(%({"a": "b"}), "#{tempdir}/core/abc-123-def.json") }
@@ -148,7 +148,7 @@
       it { is_expected.to eq('a' => 'b') }
     end
 
-    context 'written in yaml read in json mode' do
+    context 'when the backup is in yaml but the mode is :json' do
       subject { core.load_from_file_by_id('abc-123-def') }
 
       before { core.write_file(%(---\na: b), "#{tempdir}/core/abc-123-def.yaml") }
@@ -158,7 +158,7 @@
       it { is_expected.to eq('a' => 'b') }
     end
 
-    context 'Integer as parameter' do
+    context 'with Integer as parameter' do
       subject { core.load_from_file_by_id(12_345) }
 
       before { core.write_file(%(---\na: b), "#{tempdir}/core/12345.yaml") }
@@ -170,9 +170,9 @@
   end
 
   describe '#write_file' do
-    subject { core.write_file('abc123', "#{tempdir}/core/abc-123-def.json") }
+    subject(:write_file) { core.write_file('abc123', "#{tempdir}/core/abc-123-def.json") }
 
-    let(:file_like_object) { double }
+    let(:file_like_object) { instance_double(File) }
 
     it 'writes a file to abc-123-def.json' do
       allow(File).to receive(:open).and_call_original
@@ -180,7 +180,7 @@
       allow(file_like_object).to receive(:write)
       allow(file_like_object).to receive(:close)
 
-      subject
+      write_file
 
       expect(file_like_object).to have_received(:write).with('abc123')
     end
diff --git a/spec/datadog_backup/monitors_spec.rb b/spec/datadog_backup/monitors_spec.rb
index eb026ba..090e057 100644
--- a/spec/datadog_backup/monitors_spec.rb
+++ b/spec/datadog_backup/monitors_spec.rb
@@ -16,7 +16,6 @@
     allow(monitors).to receive(:api_service).and_return(api_client_double)
     return monitors
   end
-
   let(:monitor_description) do
     {
       'query' => 'bar',
@@ -35,22 +34,8 @@
       'query' => 'bar'
     }
   end
-  let(:all_monitors) do
-    [
-      200,
-      {},
-      [
-        monitor_description
-      ]
-    ]
-  end
-  let(:example_monitor) do
-    [
-      200,
-      {},
-      monitor_description
-    ]
-  end
+  let(:all_monitors) { respond_with200([monitor_description]) }
+  let(:example_monitor) { respond_with200(monitor_description) }
 
   before do
     stubs.get('/api/v1/monitor') { all_monitors }
@@ -67,22 +52,21 @@
     subject { monitors.backup }
 
     it 'is expected to create a file' do
-      file = double('file')
+      file = instance_double(File)
       allow(File).to receive(:open).with(monitors.filename(123_455), 'w').and_return(file)
-      expect(file).to receive(:write).with(::JSON.pretty_generate(clean_monitor_description))
+      allow(file).to receive(:write)
       allow(file).to receive(:close)
 
       monitors.backup
+      expect(file).to have_received(:write).with(::JSON.pretty_generate(clean_monitor_description))
     end
   end
 
   describe '#diff and #except' do
     example 'it ignores `overall_state` and `overall_state_modified`' do
       monitors.write_file(monitors.dump(monitor_description), monitors.filename(123_455))
-      stubs.get('/api/v1/dashboard/123455') {
-        [
-          200,
-          {},
+      stubs.get('/api/v1/dashboard/123455') do
+        respond_with200(
           [
             {
               'query' => 'bar',
@@ -93,8 +77,8 @@
               'overall_state_modified' => '9999-07-27T22:55:55+00:00'
             }
           ]
-        ]
-      }
+        )
+      end
 
       expect(monitors.diff(123_455)).to eq ''
 
@@ -109,13 +93,13 @@
   end
 
   describe '#get_by_id' do
-    context 'Integer' do
+    context 'when Integer' do
       subject { monitors.get_by_id(123_455) }
 
       it { is_expected.to eq monitor_description }
     end
 
-    context 'String' do
+    context 'when String' do
       subject { monitors.get_by_id('123455') }
 
       it { is_expected.to eq monitor_description }
diff --git a/spec/datadog_backup/synthetics_spec.rb b/spec/datadog_backup/synthetics_spec.rb
new file mode 100644
index 0000000..c1e4d82
--- /dev/null
+++ b/spec/datadog_backup/synthetics_spec.rb
@@ -0,0 +1,258 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe DatadogBackup::Synthetics do
+  let(:stubs) { Faraday::Adapter::Test::Stubs.new }
+  let(:api_client_double) { Faraday.new { |f| f.adapter :test, stubs } }
+  let(:tempdir) { Dir.mktmpdir } # TODO: delete afterward
+  let(:synthetics) do
+    synthetics = described_class.new(
+      action: 'backup',
+      backup_dir: tempdir,
+      output_format: :json,
+      resources: []
+    )
+    allow(synthetics).to receive(:api_service).and_return(api_client_double)
+    return synthetics
+  end
+  let(:api_test) do
+    { 'config' => { 'assertions' => [{ 'operator' => 'contains', 'property' => 'set-cookie', 'target' => '_user_id', 'type' => 'header' },
+                                     { 'operator' => 'contains', 'target' => 'body message', 'type' => 'body' },
+                                     { 'operator' => 'is', 'property' => 'content-type', 'target' => 'text/html; charset=utf-8', 'type' => 'header' },
+                                     { 'operator' => 'is', 'target' => 200, 'type' => 'statusCode' },
+                                     { 'operator' => 'lessThan', 'target' => 5000, 'type' => 'responseTime' }],
+                    'request' => { 'headers' => { 'User-Agent' => 'Mozilla/5.0 (X11; Fedora; Linux x86_64; rv:65.0) Gecko/20100101 Firefox/65.0',
+                                                  'cookie' => '_a=12345; _example_session=abc123' },
+                                   'method' => 'GET',
+                                   'url' => 'https://www.example.com/' } },
+      'creator' => { 'email' => 'user@example.com', 'handle' => 'user@example.com', 'name' => 'Hugh Zer' },
+      'locations' => ['aws:ap-northeast-1', 'aws:eu-central-1', 'aws:eu-west-2', 'aws:us-west-2'],
+      'message' => 'TEST: This is a test',
+      'monitor_id' => 12_345,
+      'name' => 'TEST: This is a test',
+      'options' => { 'follow_redirects' => true,
+                     'httpVersion' => 'http1',
+                     'min_failure_duration' => 120,
+                     'min_location_failed' => 2,
+                     'monitor_options' => { 'renotify_interval' => 0 },
+                     'monitor_priority' => 1,
+                     'retry' => { 'count' => 1, 'interval' => 500 },
+                     'tick_every' => 120 },
+      'public_id' => 'abc-123-def',
+      'status' => 'live',
+      'subtype' => 'http',
+      'tags' => ['env:test'],
+      'type' => 'api' }
+  end
+  let(:browser_test) do
+    { 'config' => { 'assertions' => [],
+                    'configVariables' => [],
+                    'request' => { 'headers' => {}, 'method' => 'GET', 'url' => 'https://www.example.com' },
+                    'setCookie' => nil,
+                    'variables' => [] },
+      'creator' => { 'email' => 'user@example.com',
+                     'handle' => 'user@example.com',
+                     'name' => 'Hugh Zer' },
+      'locations' => ['aws:us-east-2'],
+      'message' => 'Test message',
+      'monitor_id' => 12_345,
+      'name' => 'www.example.com',
+      'options' => { 'ci' => { 'executionRule' => 'non_blocking' },
+                     'device_ids' => ['chrome.laptop_large', 'chrome.mobile_small'],
+                     'disableCors' => false,
+                     'disableCsp' => false,
+                     'ignoreServerCertificateError' => false,
+                     'min_failure_duration' => 300,
+                     'min_location_failed' => 1,
+                     'monitor_options' => { 'renotify_interval' => 0 },
+                     'noScreenshot' => false,
+                     'retry' => { 'count' => 0, 'interval' => 1000 },
+                     'tick_every' => 900 },
+      'public_id' => '456-ghi-789',
+      'status' => 'live',
+      'tags' => ['env:test'],
+      'type' => 'browser' }
+  end
+  let(:all_synthetics) { respond_with200({ 'tests' => [api_test, browser_test] }) }
+  let(:api_synthetic) { respond_with200(api_test) }
+  let(:browser_synthetic) { respond_with200(browser_test) }
+
+  before do
+    stubs.get('/api/v1/synthetics/tests') { all_synthetics }
+    stubs.get('/api/v1/synthetics/tests/api/abc-123-def') { api_synthetic }
+    stubs.get('/api/v1/synthetics/tests/browser/456-ghi-789') { browser_synthetic }
+  end
+
+  describe '#all' do
+    subject { synthetics.all }
+
+    it { is_expected.to contain_exactly(api_test, browser_test) }
+  end
+
+  describe '#backup' do
+    subject(:backup) { synthetics.backup }
+
+    let(:apifile) { instance_double(File) }
+    let(:browserfile) { instance_double(File) }
+
+    before do
+      allow(File).to receive(:open).with(synthetics.filename('abc-123-def'), 'w').and_return(apifile)
+      allow(File).to receive(:open).with(synthetics.filename('456-ghi-789'), 'w').and_return(browserfile)
+      allow(apifile).to receive(:write)
+      allow(apifile).to receive(:close)
+      allow(browserfile).to receive(:write)
+      allow(browserfile).to receive(:close)
+    end
+
+    it 'is expected to write the API test' do
+      backup
+      expect(apifile).to have_received(:write).with(::JSON.pretty_generate(api_test))
+    end
+
+    it 'is expected to write the browser test' do
+      backup
+      expect(browserfile).to have_received(:write).with(::JSON.pretty_generate(browser_test))
+    end
+  end
+
+  describe '#filename' do
+    subject { synthetics.filename('abc-123-def') }
+
+    it { is_expected.to eq("#{tempdir}/synthetics/abc-123-def.json") }
+  end
+
+  describe '#get_by_id' do
+    context 'when the type is api' do
+      subject { synthetics.get_by_id('abc-123-def') }
+
+      it { is_expected.to eq api_test }
+    end
+
+    context 'when the type is browser' do
+      subject { synthetics.get_by_id('456-ghi-789') }
+
+      it { is_expected.to eq browser_test }
+    end
+  end
+
+  describe '#diff' do # TODO: migrate to core_spec.rb, since #diff is not defined here.
+    subject { synthetics.diff('abc-123-def') }
+
+    before do
+      synthetics.write_file(synthetics.dump(api_test), synthetics.filename('abc-123-def'))
+    end
+
+    context 'when the test is identical' do
+      it { is_expected.to be_empty }
+    end
+
+    context 'when the remote is not found' do
+      subject(:invalid_diff) { synthetics.diff('invalid-id') }
+
+      before do
+        synthetics.write_file(synthetics.dump({ 'name' => 'invalid-diff' }), synthetics.filename('invalid-id'))
+      end
+
+      it {
+        expect(invalid_diff).to eq(%(---- {}\n+---\n+name: invalid-diff))
+      }
+    end
+
+    context 'when there is a local update' do
+      before do
+        different_test = api_test.dup
+        different_test['message'] = 'Different message'
+        synthetics.write_file(synthetics.dump(different_test), synthetics.filename('abc-123-def'))
+      end
+
+      it { is_expected.to include(%(-message: 'TEST: This is a test'\n+message: Different message)) }
+    end
+  end
+
+  describe '#create' do
+    context 'when the type is api' do
+      subject(:create) { synthetics.create({ 'type' => 'api' }) }
+
+      before do
+        stubs.post('/api/v1/synthetics/tests/api') { respond_with200({ 'public_id' => 'api-create-abc' }) }
+      end
+
+      it { is_expected.to eq({ 'public_id' => 'api-create-abc' }) }
+    end
+
+    context 'when the type is browser' do
+      subject(:create) { synthetics.create({ 'type' => 'browser' }) }
+
+      before do
+        stubs.post('/api/v1/synthetics/tests/browser') { respond_with200({ 'public_id' => 'browser-create-abc' }) }
+      end
+
+      it { is_expected.to eq({ 'public_id' => 'browser-create-abc' }) }
+    end
+  end
+
+  describe '#update' do
+    context 'when the type is api' do
+      subject(:update) { synthetics.update('api-update-abc', { 'type' => 'api' }) }
+
+      before do
+        stubs.put('/api/v1/synthetics/tests/api/api-update-abc') { respond_with200({ 'public_id' => 'api-update-abc' }) }
+      end
+
+      it { is_expected.to eq({ 'public_id' => 'api-update-abc' }) }
+    end
+
+    context 'when the type is browser' do
+      subject(:update) { synthetics.update('browser-update-abc', { 'type' => 'browser' }) }
+
+      before do
+        stubs.put('/api/v1/synthetics/tests/browser/browser-update-abc') { respond_with200({ 'public_id' => 'browser-update-abc' }) }
+      end
+
+      it { is_expected.to eq({ 'public_id' => 'browser-update-abc' }) }
+    end
+  end
+
+  describe '#restore' do
+    context 'when the id exists' do
+      subject { synthetics.restore('abc-123-def') }
+
+      before do
+        synthetics.write_file(synthetics.dump({ 'name' => 'restore-valid-id', 'type' => 'api' }), synthetics.filename('abc-123-def'))
+        stubs.put('/api/v1/synthetics/tests/api/abc-123-def') { respond_with200({ 'public_id' => 'abc-123-def', 'type' => 'api' }) }
+      end
+
+      it { is_expected.to eq({ 'public_id' => 'abc-123-def', 'type' => 'api' }) }
+    end
+
+    context 'when the id does not exist' do
+      subject(:restore) { synthetics.restore('restore-invalid-id') }
+
+      before do
+        synthetics.write_file(synthetics.dump({ 'name' => 'restore-invalid-id', 'type' => 'api' }), synthetics.filename('restore-invalid-id'))
+        stubs.put('/api/v1/synthetics/tests/api/restore-invalid-id') { [404, {}, ''] }
+        stubs.post('/api/v1/synthetics/tests/api') { respond_with200({ 'public_id' => 'restore-valid-id' }) }
+        allow(synthetics).to receive(:create).and_call_original
+        allow(synthetics).to receive(:all).and_return([api_test, browser_test, { 'public_id' => 'restore-valid-id', 'type' => 'api' }])
+      end
+
+      it { is_expected.to eq({ 'type' => 'api' }) }
+
+      it 'calls create with the contents of the original file' do
+        restore
+        expect(synthetics).to have_received(:create).with({ 'name' => 'restore-invalid-id', 'type' => 'api' })
+      end
+
+      it 'deletes the original file' do
+        restore
+        expect(File.exist?(synthetics.filename('restore-invalid-id'))).to be false
+      end
+
+      it 'creates a new file with the restored contents' do
+        restore
+        expect(File.exist?(synthetics.filename('restore-valid-id'))).to be true
+      end
+    end
+  end
+end
diff --git a/spec/datadog_backup_bin_spec.rb b/spec/datadog_backup_bin_spec.rb
index 9360033..44ae87f 100644
--- a/spec/datadog_backup_bin_spec.rb
+++ b/spec/datadog_backup_bin_spec.rb
@@ -3,13 +3,13 @@
 require 'open3'
 require 'timeout'
 
-describe 'bin/datadog_backup' do
+describe 'bin/datadog_backup' do # rubocop:disable RSpec/DescribeClass
   # Contract Or[nil,String] => self
   def run_bin(env = {}, args = '')
     status = nil
     output = ''
     cmd = "bin/datadog_backup #{args}"
-    Open3.popen2e(env, cmd) do |i, oe, t|
+    Open3.popen2e(env, cmd) do |_i, oe, t|
       pid = t.pid
 
       Timeout.timeout(4.0) do
@@ -44,9 +44,17 @@ def run_bin(env = {}, args = '')
     end
   end
 
-  it 'supplies help' do
-    out_err, status = run_bin(env, '--help')
-    expect(out_err).to match(/Usage: DD_API_KEY=/)
-    expect(status).to be_success
+  describe 'help' do
+    subject(:bin) { run_bin(env, '--help') }
+
+    it 'prints usage' do
+      out_err, _status = bin
+      expect(out_err).to match(/Usage: DD_API_KEY=/)
+    end
+
+    it 'exits cleanly' do
+      _out_err, status = bin
+      expect(status).to be_success
+    end
   end
 end
diff --git a/spec/datadog_backup_spec.rb b/spec/datadog_backup_spec.rb
deleted file mode 100644
index e08c368..0000000
--- a/spec/datadog_backup_spec.rb
+++ /dev/null
@@ -1,6 +0,0 @@
-# frozen_string_literal: true
-
-require 'spec_helper'
-
-describe DatadogBackup do
-end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 4b2c71c..e784e1e 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -11,8 +11,6 @@
 require 'tmpdir'
 require 'datadog_backup'
 
-
-
 SPEC_ROOT = __dir__
 WORK_ROOT = File.expand_path(File.join(SPEC_ROOT, '..'))
 
@@ -38,3 +36,7 @@
 
   Kernel.srand config.seed
 end
+
+def respond_with200(body)
+  [200, {}, body]
+end