Create base class for resource events

Derived ResourceMilestoneEvent,
ResourceWeightEvent and ResourceLabelEvent
from ResourceEvent

Also added missing specs for resource events.

Remove resource on ResourceMilestoneEvent

app/models/concerns/resource_event_tools.rb → app/models/resource_event.rb

 # frozen_string_literal: true
 
-module ResourceEventTools
-  extend ActiveSupport::Concern
+class ResourceEvent < ApplicationRecord
+  include Gitlab::Utils::StrongMemoize
+  include Importable
 
-  included do
-    belongs_to :user
+  self.abstract_class = true
 
   validates :user, presence: { unless: :importing? }, on: :create
 
-    validate :exactly_one_issuable
+  belongs_to :user
 
   scope :created_after, ->(time) { where('created_at > ?', time) }
+
+  def discussion_id
+    strong_memoize(:discussion_id) do
+      Digest::SHA1.hexdigest(discussion_id_key.join("-"))
+    end
+  end
+
+  private
+
+  def discussion_id_key
+    [self.class.name, created_at, user_id]
   end
 
   def exactly_one_issuable

app/models/resource_label_event.rb

 # frozen_string_literal: true
 
-class ResourceLabelEvent < ApplicationRecord
-  include Importable
-  include Gitlab::Utils::StrongMemoize
+class ResourceLabelEvent < ResourceEvent
   include CacheMarkdownField
-  include ResourceEventTools
 
   cache_markdown_field :reference
 
@@ -13,8 +10,11 @@ class ResourceLabelEvent < ApplicationRecord
   belongs_to :label
 
   scope :inc_relations, -> { includes(:label, :user) }
+  scope :by_issue, ->(issue) { where(issue_id: issue.id) }
+  scope :by_merge_request, ->(merge_request) { where(merge_request_id: merge_request.id) }
 
   validates :label, presence: { unless: :importing? }, on: :create
+  validate :exactly_one_issuable
 
   after_save :expire_etag_cache
   after_destroy :expire_etag_cache
@@ -41,12 +41,6 @@ class ResourceLabelEvent < ApplicationRecord
     issue || merge_request
   end
 
-  def discussion_id(resource = nil)
-    strong_memoize(:discussion_id) do
-      Digest::SHA1.hexdigest(discussion_id_key.join("-"))
-    end
-  end
-
   def project
     issuable.project
   end
@@ -109,10 +103,6 @@ class ResourceLabelEvent < ApplicationRecord
   def resource_parent
     issuable.project || issuable.group
   end
-
-  def discussion_id_key
-    [self.class.name, created_at, user_id]
-  end
 end
 
 ResourceLabelEvent.prepend_if_ee('EE::ResourceLabelEvent')

app/models/resource_milestone_event.rb

 # frozen_string_literal: true
 
-class ResourceMilestoneEvent < ApplicationRecord
-  include Gitlab::Utils::StrongMemoize
-  include Importable
-  include ResourceEventTools
-
+class ResourceMilestoneEvent < ResourceEvent
   belongs_to :issue
   belongs_to :merge_request
   belongs_to :milestone
@@ -12,6 +8,8 @@ class ResourceMilestoneEvent < ApplicationRecord
   scope :by_issue, ->(issue) { where(issue_id: issue.id) }
   scope :by_merge_request, ->(merge_request) { where(merge_request_id: merge_request.id) }
 
+  validate :exactly_one_issuable
+
   enum action: {
          add: 1,
          remove: 2
@@ -23,8 +21,4 @@ class ResourceMilestoneEvent < ApplicationRecord
   def self.issuable_attrs
     %i(issue merge_request).freeze
   end
-
-  def resource
-    issue || merge_request
-  end
 end

app/models/resource_weight_event.rb

 # frozen_string_literal: true
 
-class ResourceWeightEvent < ApplicationRecord
-  include Gitlab::Utils::StrongMemoize
-
-  validates :user, presence: true
+class ResourceWeightEvent < ResourceEvent
   validates :issue, presence: true
 
-  belongs_to :user
   belongs_to :issue
 
   scope :by_issue, ->(issue) { where(issue_id: issue.id) }
-  scope :created_after, ->(time) { where('created_at > ?', time) }
-
-  def discussion_id(resource = nil)
-    strong_memoize(:discussion_id) do
-      Digest::SHA1.hexdigest(discussion_id_key.join("-"))
-    end
-  end
-
-  private
-
-  def discussion_id_key
-    [self.class.name, created_at, user_id]
-  end
 end

spec/models/resource_label_event_spec.rb

@@ -10,6 +10,10 @@ RSpec.describe ResourceLabelEvent, type: :model do
 
   it_behaves_like 'having unique enum values'
 
+  it_behaves_like 'a resource event'
+  it_behaves_like 'a resource event for issues'
+  it_behaves_like 'a resource event for merge requests'
+
   describe 'associations' do
     it { is_expected.to belong_to(:user) }
     it { is_expected.to belong_to(:issue) }

spec/models/resource_weight_event_spec.rb

@@ -3,6 +3,9 @@
 require 'spec_helper'
 
 RSpec.describe ResourceWeightEvent, type: :model do
+  it_behaves_like 'a resource event'
+  it_behaves_like 'a resource event for issues'
+
   let_it_be(:user1) { create(:user) }
   let_it_be(:user2) { create(:user) }
 
@@ -11,13 +14,11 @@ RSpec.describe ResourceWeightEvent, type: :model do
   let_it_be(:issue3) { create(:issue, author: user2) }
 
   describe 'validations' do
-    it { is_expected.not_to allow_value(nil).for(:user) }
     it { is_expected.not_to allow_value(nil).for(:issue) }
     it { is_expected.to allow_value(nil).for(:weight) }
   end
 
   describe 'associations' do
-    it { is_expected.to belong_to(:user) }
     it { is_expected.to belong_to(:issue) }
   end
 

spec/support/shared_examples/resource_events.rb

@@ -10,8 +10,21 @@ shared_examples 'a resource event' do
   let_it_be(:issue2) { create(:issue, author: user1) }
   let_it_be(:issue3) { create(:issue, author: user2) }
 
+  describe 'importable' do
+    it { is_expected.to respond_to(:importing?) }
+    it { is_expected.to respond_to(:imported?) }
+  end
+
   describe 'validations' do
     it { is_expected.not_to allow_value(nil).for(:user) }
+
+    context 'when importing' do
+      before do
+        allow(subject).to receive(:importing?).and_return(true)
+      end
+
+      it { is_expected.to allow_value(nil).for(:user) }
+    end
   end
 
   describe 'associations' do