Refactoring: Splitted up instance_action statistics diff for different usages.

lib/sequencer/unit/import/common/model/statistics/diff.rb

@@ -1,4 +1,4 @@
-require 'sequencer/unit/import/common/model/statistics/mixin/diff'
+require 'sequencer/unit/import/common/model/statistics/mixin/instance_action_diff'
 
 class Sequencer
   class Unit
@@ -7,7 +7,7 @@ class Sequencer
         module Model
           module Statistics
             class Diff < Sequencer::Unit::Base
-              include ::Sequencer::Unit::Import::Common::Model::Statistics::Mixin::Diff
+              include ::Sequencer::Unit::Import::Common::Model::Statistics::Mixin::InstanceActionDiff
 
               def process
                 state.provide(:statistics_diff, diff)

lib/sequencer/unit/import/common/model/statistics/mixin/common.rb

@@ -0,0 +1,29 @@
+class Sequencer
+  class Unit
+    module Import
+      module Common
+        module Model
+          module Statistics
+            module Mixin
+              module Common
+                private
+
+                def actions
+                  %i[skipped created updated unchanged failed deactivated]
+                end
+
+                def empty_diff
+                  possible_actions.collect { |key| [key, 0] }.to_h
+                end
+
+                def possible_actions
+                  @possible_actions ||= actions
+                end
+              end
+            end
+          end
+        end
+      end
+    end
+  end
+end

lib/sequencer/unit/import/common/model/statistics/mixin/empty_diff.rb

@@ -0,0 +1,25 @@
+require 'sequencer/unit/import/common/model/statistics/mixin/common'
+
+class Sequencer
+  class Unit
+    module Import
+      module Common
+        module Model
+          module Statistics
+            module Mixin
+              module EmptyDiff
+                include Sequencer::Unit::Import::Common::Model::Statistics::Mixin::Common
+
+                def self.included(base)
+                  base.provides :statistics_diff
+                end
+
+                alias diff empty_diff
+              end
+            end
+          end
+        end
+      end
+    end
+  end
+end

lib/sequencer/unit/import/common/model/statistics/mixin/instance_action_diff.rb

@@ -1,3 +1,5 @@
+require 'sequencer/unit/import/common/model/statistics/mixin/common'
+
 class Sequencer
   class Unit
     module Import
@@ -5,7 +7,8 @@ class Sequencer
         module Model
           module Statistics
             module Mixin
-              module Diff
+              module InstanceActionDiff
+                include Sequencer::Unit::Import::Common::Model::Statistics::Mixin::Common
 
                 def self.included(base)
                   base.uses :instance_action
@@ -14,13 +17,9 @@ class Sequencer
 
                 private
 
-                def actions
-                  %i[skipped created updated unchanged failed deactivated]
-                end
-
                 def diff
                   raise "Unknown action '#{instance_action}'" if !possible?
-                  defaults.merge(
+                  empty_diff.merge(
                     instance_action => 1,
                     sum: 1,
                   )
@@ -29,14 +28,6 @@ class Sequencer
                 def possible?
                   possible_actions.include?(instance_action)
                 end
-
-                def defaults
-                  possible_actions.collect { |key| [key, 0] }.to_h
-                end
-
-                def possible_actions
-                  @possible_actions ||= actions
-                end
               end
             end
           end

lib/sequencer/unit/import/exchange/folder_contact/statistics/diff.rb

@@ -5,7 +5,7 @@ class Sequencer
         module FolderContact
           module Statistics
             class Diff < Sequencer::Unit::Base
-              include ::Sequencer::Unit::Import::Common::Model::Statistics::Mixin::Diff
+              include ::Sequencer::Unit::Import::Common::Model::Statistics::Mixin::InstanceActionDiff
 
               uses :ews_folder_name