Persist and validate label based CA stages

- Add label based stage event classes
- Add label based stage events to the pairing rules
- Validate GroupLabel associations for ProjectStage and GroupStage

app/models/analytics/cycle_analytics/project_stage.rb

@@ -11,6 +11,10 @@ module Analytics
       alias_attribute :parent, :project
       alias_attribute :parent_id, :project_id
 
+      delegate :group, to: :project
+
+      validate :validate_project_group_for_label_events, if: -> { start_event_label_based? || end_event_label_based? }
+
       def self.relative_positioning_query_base(stage)
         where(project_id: stage.project_id)
       end
@@ -18,6 +22,13 @@ module Analytics
       def self.relative_positioning_parent_column
         :project_id
       end
+
+      private
+
+      # Project should belong to a group when the stage has Label based events since only GroupLabels are allowed.
+      def validate_project_group_for_label_events
+        errors.add(:project, s_('CycleAnalyticsStage|should be under a group')) unless project.group
+      end
     end
   end
 end

app/models/concerns/analytics/cycle_analytics/stage.rb

@@ -5,13 +5,20 @@ module Analytics
     module Stage
       extend ActiveSupport::Concern
       include RelativePositioning
+      include Gitlab::Utils::StrongMemoize
 
       included do
+        belongs_to :start_event_label, class_name: 'GroupLabel', optional: true
+        belongs_to :end_event_label, class_name: 'GroupLabel', optional: true
+
         validates :name, presence: true
         validates :name, exclusion: { in: Gitlab::Analytics::CycleAnalytics::DefaultStages.names }, if: :custom?
         validates :start_event_identifier, presence: true
         validates :end_event_identifier, presence: true
+        validates :start_event_label, presence: true, if: :start_event_label_based?
+        validates :end_event_label, presence: true, if: :end_event_label_based?
         validate :validate_stage_event_pairs
+        validate :validate_labels
 
         enum start_event_identifier: Gitlab::Analytics::CycleAnalytics::StageEvents.to_enum, _prefix: :start_event_identifier
         enum end_event_identifier: Gitlab::Analytics::CycleAnalytics::StageEvents.to_enum, _prefix: :end_event_identifier
@@ -30,19 +37,41 @@ module Analytics
       end
 
       def start_event
-        Gitlab::Analytics::CycleAnalytics::StageEvents[start_event_identifier].new(params_for_start_event)
+        strong_memoize(:start_event) do
+          Gitlab::Analytics::CycleAnalytics::StageEvents[start_event_identifier].new(params_for_start_event)
+        end
       end
 
       def end_event
-        Gitlab::Analytics::CycleAnalytics::StageEvents[end_event_identifier].new(params_for_end_event)
+        strong_memoize(:end_event) do
+          Gitlab::Analytics::CycleAnalytics::StageEvents[end_event_identifier].new(params_for_end_event)
+        end
+      end
+
+      def start_event_label_based?
+        start_event_identifier && start_event.label_based?
+      end
+
+      def end_event_label_based?
+        end_event_identifier && end_event.label_based?
+      end
+
+      def start_event_identifier=(identifier)
+        clear_memoization(:start_event)
+        super
+      end
+
+      def end_event_identifier=(identifier)
+        clear_memoization(:end_event)
+        super
       end
 
       def params_for_start_event
-        {}
+        start_event_label.present? ? { label: start_event_label } : {}
       end
 
       def params_for_end_event
-        {}
+        end_event_label.present? ? { label: end_event_label } : {}
       end
 
       def default_stage?
@@ -70,13 +99,34 @@ module Analytics
         return if start_event_identifier.nil? || end_event_identifier.nil?
 
         unless pairing_rules.fetch(start_event.class, []).include?(end_event.class)
-          errors.add(:end_event, :not_allowed_for_the_given_start_event)
+          errors.add(:end_event, s_('CycleAnalytics|not allowed for the given start event'))
         end
       end
 
       def pairing_rules
         Gitlab::Analytics::CycleAnalytics::StageEvents.pairing_rules
       end
+
+      def validate_labels
+        validate_label_within_group(:start_event_label, start_event_label_id) if start_event_label_id_changed?
+        validate_label_within_group(:end_event_label, end_event_label_id) if end_event_label_id_changed?
+      end
+
+      def validate_label_within_group(association_name, label_id)
+        return unless label_id
+        return unless group
+
+        unless label_available_for_group?(label_id)
+          errors.add(association_name, s_('CycleAnalyticsStage|is not available for the selected group'))
+        end
+      end
+
+      def label_available_for_group?(label_id)
+        LabelsFinder.new(nil, { group_id: group.id, include_ancestor_groups: true, only_group_labels: true })
+          .execute(skip_authorization: true)
+          .by_ids(label_id)
+          .exists?
+      end
     end
   end
 end

ee/lib/ee/gitlab/analytics/cycle_analytics/stage_events.rb

@@ -17,13 +17,25 @@ module EE
             ::Gitlab::Analytics::CycleAnalytics::StageEvents::IssueFirstAssociatedWithMilestone => 5,
             ::Gitlab::Analytics::CycleAnalytics::StageEvents::IssueFirstMentionedInCommit => 6,
             ::Gitlab::Analytics::CycleAnalytics::StageEvents::IssueLastEdited => 7,
+            ::Gitlab::Analytics::CycleAnalytics::StageEvents::IssueLabelAdded => 8,
+            ::Gitlab::Analytics::CycleAnalytics::StageEvents::IssueLabelRemoved => 9,
             ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestClosed => 105,
-            ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLastEdited => 106
+            ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLastEdited => 106,
+            ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLabelAdded => 107,
+            ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLabelRemoved => 108
           }.freeze
 
           EE_EVENTS = EE_ENUM_MAPPING.keys.freeze
 
           EE_PAIRING_RULES = {
+            ::Gitlab::Analytics::CycleAnalytics::StageEvents::IssueLabelAdded => [
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::IssueLabelAdded,
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::IssueLabelRemoved,
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::IssueClosed
+            ],
+            ::Gitlab::Analytics::CycleAnalytics::StageEvents::IssueLabelRemoved => [
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::IssueClosed
+            ],
             ::Gitlab::Analytics::CycleAnalytics::StageEvents::IssueCreated => [
               ::Gitlab::Analytics::CycleAnalytics::StageEvents::IssueClosed,
               ::Gitlab::Analytics::CycleAnalytics::StageEvents::IssueFirstAddedToBoard,
@@ -50,38 +62,60 @@ module EE
               ::Gitlab::Analytics::CycleAnalytics::StageEvents::IssueLastEdited
             ],
             ::Gitlab::Analytics::CycleAnalytics::StageEvents::IssueClosed => [
-              ::Gitlab::Analytics::CycleAnalytics::StageEvents::IssueLastEdited
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::IssueLastEdited,
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::IssueLabelAdded,
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::IssueLabelRemoved
             ],
             ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestCreated => [
               ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestClosed,
               ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestFirstDeployedToProduction,
               ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLastBuildStarted,
               ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLastBuildFinished,
-              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLastEdited
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLastEdited,
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLabelAdded,
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLabelRemoved
             ],
             ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestClosed => [
               ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestFirstDeployedToProduction,
-              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLastEdited
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLastEdited,
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLabelAdded,
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLabelRemoved
             ],
             ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestFirstDeployedToProduction => [
-              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLastEdited
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLastEdited,
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLabelAdded,
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLabelRemoved
             ],
             ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLastBuildStarted => [
               ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestClosed,
               ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestFirstDeployedToProduction,
               ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLastEdited,
-              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestMerged
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestMerged,
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLabelAdded,
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLabelRemoved
             ],
             ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLastBuildFinished => [
               ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestClosed,
               ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestFirstDeployedToProduction,
               ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLastEdited,
-              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestMerged
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestMerged,
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLabelAdded,
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLabelRemoved
             ],
             ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestMerged => [
               ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestClosed,
               ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestFirstDeployedToProduction,
-              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLastEdited
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLastEdited,
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLabelAdded,
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLabelRemoved
+            ],
+            ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLabelAdded => [
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLabelAdded,
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLabelRemoved
+            ],
+            ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLabelRemoved => [
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLabelAdded,
+              ::Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLabelRemoved
             ]
           }.freeze
 

ee/lib/gitlab/analytics/cycle_analytics/stage_events/issue_label_added.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Analytics
+    module CycleAnalytics
+      module StageEvents
+        class IssueLabelAdded < LabelBasedStageEvent
+          def self.name
+            s_("CycleAnalyticsEvent|Issue label was added")
+          end
+
+          def self.identifier
+            :issue_label_added
+          end
+
+          def object_type
+            Issue
+          end
+        end
+      end
+    end
+  end
+end

ee/lib/gitlab/analytics/cycle_analytics/stage_events/issue_label_removed.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Analytics
+    module CycleAnalytics
+      module StageEvents
+        class IssueLabelRemoved < LabelBasedStageEvent
+          def self.name
+            s_("CycleAnalyticsEvent|Issue label was removed")
+          end
+
+          def self.identifier
+            :issue_label_removed
+          end
+
+          def object_type
+            Issue
+          end
+        end
+      end
+    end
+  end
+end

ee/lib/gitlab/analytics/cycle_analytics/stage_events/label_based_stage_event.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Analytics
+    module CycleAnalytics
+      module StageEvents
+        # Represents an event that is related to label creation or removal, this model requires a label provided by the user
+        class LabelBasedStageEvent < StageEvent
+          def label_based?
+            true
+          end
+        end
+      end
+    end
+  end
+end

ee/lib/gitlab/analytics/cycle_analytics/stage_events/merge_request_label_added.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Analytics
+    module CycleAnalytics
+      module StageEvents
+        class MergeRequestLabelAdded < LabelBasedStageEvent
+          def self.name
+            s_("CycleAnalyticsEvent|Merge Request label was added")
+          end
+
+          def self.identifier
+            :merge_request_label_added
+          end
+
+          def object_type
+            MergeRequest
+          end
+        end
+      end
+    end
+  end
+end

ee/lib/gitlab/analytics/cycle_analytics/stage_events/merge_request_label_removed.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Analytics
+    module CycleAnalytics
+      module StageEvents
+        class MergeRequestLabelRemoved < LabelBasedStageEvent
+          def self.name
+            s_("CycleAnalyticsEvent|Merge Request label was removed")
+          end
+
+          def self.identifier
+            :merge_request_label_removed
+          end
+
+          def object_type
+            MergeRequest
+          end
+        end
+      end
+    end
+  end
+end

ee/spec/lib/gitlab/analytics/cycle_analytics/stage_events/issue_label_added_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Gitlab::Analytics::CycleAnalytics::StageEvents::IssueLabelAdded do
+  it_behaves_like 'cycle analytics event' do
+    let(:params) { { label: GroupLabel.new } }
+  end
+end

ee/spec/lib/gitlab/analytics/cycle_analytics/stage_events/issue_label_removed_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Gitlab::Analytics::CycleAnalytics::StageEvents::IssueLabelRemoved do
+  it_behaves_like 'cycle analytics event' do
+    let(:params) { { label: GroupLabel.new } }
+  end
+end

ee/spec/lib/gitlab/analytics/cycle_analytics/stage_events/merge_request_label_added_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLabelAdded do
+  it_behaves_like 'cycle analytics event' do
+    let(:params) { { label: GroupLabel.new } }
+  end
+end

ee/spec/lib/gitlab/analytics/cycle_analytics/stage_events/merge_request_label_removed_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestLabelRemoved do
+  it_behaves_like 'cycle analytics event' do
+    let(:params) { { label: GroupLabel.new } }
+  end
+end

ee/spec/models/analytics/cycle_analytics/group_stage_spec.rb

@@ -12,11 +12,18 @@ describe Analytics::CycleAnalytics::GroupStage do
     let(:parent_name) { :group }
   end
 
+  include_examples 'cycle analytics label based stage' do
+    let_it_be(:parent) { create(:group) }
+    let_it_be(:parent_in_subgroup) { create(:group, parent: parent) }
+    let_it_be(:group_label) { create(:group_label, group: parent) }
+    let_it_be(:parent_outside_of_group_label_scope) { create(:group) }
+  end
+
   context 'relative positioning' do
     it_behaves_like 'a class that supports relative positioning' do
-      let(:group) { create(:group) }
+      let(:parent) { create(:group) }
       let(:factory) { :cycle_analytics_group_stage }
-      let(:default_params) { { group: group } }
+      let(:default_params) { { group: parent } }
     end
   end
 end

ee/spec/models/analytics/cycle_analytics/project_stage_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Analytics::CycleAnalytics::ProjectStage do
+  include_examples 'cycle analytics label based stage' do
+    let_it_be(:group) { create(:group) }
+    let_it_be(:parent) { create(:project, group: group) }
+    let_it_be(:parent_in_subgroup) { create(:project, group: create(:group, parent: group)) }
+    let_it_be(:group_label) { create(:group_label, group: group) }
+    let_it_be(:parent_outside_of_group_label_scope) { create(:project, group: create(:group)) }
+  end
+
+  context 'project without group' do
+    it 'returns validation error when end event is label based' do
+      stage = described_class.new({
+        name: 'My Stage',
+        parent: create(:project),
+        start_event_identifier: :issue_closed,
+        end_event_identifier: :issue_label_added,
+        end_event_label: create(:group_label)
+      })
+
+      expect(stage).to be_invalid
+      expect(stage.errors[:project]).to include(s_('CycleAnalyticsStage|should be under a group'))
+    end
+
+    it 'returns validation error when start event is label based' do
+      stage = described_class.new({
+        name: 'My Stage',
+        parent: create(:project),
+        start_event_identifier: :issue_label_added,
+        start_event_label: create(:group_label),
+        end_event_identifier: :issue_closed
+      })
+
+      expect(stage).to be_invalid
+      expect(stage.errors[:project]).to include(s_('CycleAnalyticsStage|should be under a group'))
+    end
+  end
+end

lib/gitlab/analytics/cycle_analytics/stage_events/stage_event.rb

@@ -35,6 +35,10 @@ module Gitlab
             query
           end
 
+          def label_based?
+            false
+          end
+
           private
 
           attr_reader :params

locale/gitlab.pot

@@ -5081,9 +5081,21 @@ msgstr ""
 msgid "CycleAnalyticsEvent|Issue first mentioned in a commit"
 msgstr ""
 
+msgid "CycleAnalyticsEvent|Issue label was added"
+msgstr ""
+
+msgid "CycleAnalyticsEvent|Issue label was removed"
+msgstr ""
+
 msgid "CycleAnalyticsEvent|Issue last edited"
 msgstr ""
 
+msgid "CycleAnalyticsEvent|Merge Request label was added"
+msgstr ""
+
+msgid "CycleAnalyticsEvent|Merge Request label was removed"
+msgstr ""
+
 msgid "CycleAnalyticsEvent|Merge request closed"
 msgstr ""
 
@@ -5126,6 +5138,12 @@ msgstr ""
 msgid "CycleAnalyticsStage|Test"
 msgstr ""
 
+msgid "CycleAnalyticsStage|is not available for the selected group"
+msgstr ""
+
+msgid "CycleAnalyticsStage|should be under a group"
+msgstr ""
+
 msgid "CycleAnalytics|%{projectName}"
 msgid_plural "CycleAnalytics|%d projects selected"
 msgstr[0] ""
@@ -5145,6 +5163,9 @@ msgstr ""
 msgid "CycleAnalytics|group dropdown filter"
 msgstr ""
 
+msgid "CycleAnalytics|not allowed for the given start event"
+msgstr ""
+
 msgid "CycleAnalytics|project dropdown filter"
 msgstr ""
 

spec/support/shared_examples/cycle_analytics_event_shared_examples.rb

 # frozen_string_literal: true
 
 shared_examples_for 'cycle analytics event' do
-  let(:instance) { described_class.new({}) }
+  let(:params) { {} }
+  let(:instance) { described_class.new(params) }
 
   it { expect(described_class.name).to be_a_kind_of(String) }
   it { expect(described_class.identifier).to be_a_kind_of(Symbol) }

spec/support/shared_examples/cycle_analytics_stage_shared_examples.rb

@@ -10,6 +10,11 @@ shared_examples_for 'cycle analytics stage' do
     }
   end
 
+  describe 'associations' do
+    it { is_expected.to belong_to(:end_event_label) }
+    it { is_expected.to belong_to(:start_event_label) }
+  end
+
   describe 'validation' do
     it 'is valid' do
       expect(described_class.new(valid_params)).to be_valid
@@ -18,22 +23,22 @@ shared_examples_for 'cycle analytics stage' do
     it 'validates presence of parent' do
       stage = described_class.new(valid_params.except(:parent))
 
-      expect(stage).not_to be_valid
-      expect(stage.errors.details[parent_name]).to eq([{ error: :blank }])
+      expect(stage).to be_invalid
+      expect(stage.errors[parent_name]).to include("can't be blank")
     end
 
     it 'validates presence of start_event_identifier' do
       stage = described_class.new(valid_params.except(:start_event_identifier))
 
-      expect(stage).not_to be_valid
-      expect(stage.errors.details[:start_event_identifier]).to eq([{ error: :blank }])
+      expect(stage).to be_invalid
+      expect(stage.errors[:start_event_identifier]).to include("can't be blank")
     end
 
     it 'validates presence of end_event_identifier' do
       stage = described_class.new(valid_params.except(:end_event_identifier))
 
-      expect(stage).not_to be_valid
-      expect(stage.errors.details[:end_event_identifier]).to eq([{ error: :blank }])
+      expect(stage).to be_invalid
+      expect(stage.errors[:end_event_identifier]).to include("can't be blank")
     end
 
     it 'is invalid when end_event is not allowed for the given start_event' do
@@ -43,8 +48,8 @@ shared_examples_for 'cycle analytics stage' do
       )
       stage = described_class.new(invalid_params)
 
-      expect(stage).not_to be_valid
-      expect(stage.errors.details[:end_event]).to eq([{ error: :not_allowed_for_the_given_start_event }])
+      expect(stage).to be_invalid
+      expect(stage.errors[:end_event]).to include(s_('CycleAnalytics|not allowed for the given start event'))
     end
 
     context 'disallows default stage names when creating custom stage' do
@@ -105,3 +110,119 @@ shared_examples_for 'cycle analytics stage' do
     end
   end
 end
+
+shared_examples_for 'cycle analytics label based stage' do
+  context 'when creating label based event' do
+    context 'when the label id is not passed' do
+      it 'returns validation error when `start_event_label_id` is missing' do
+        stage = described_class.new({
+          name: 'My Stage',
+          parent: parent,
+          start_event_identifier: :issue_label_added,
+          end_event_identifier: :issue_closed
+        })
+
+        expect(stage).to be_invalid
+        expect(stage.errors[:start_event_label]).to include("can't be blank")
+      end
+
+      it 'returns validation error when `end_event_label_id` is missing' do
+        stage = described_class.new({
+          name: 'My Stage',
+          parent: parent,
+          start_event_identifier: :issue_closed,
+          end_event_identifier: :issue_label_added
+        })
+
+        expect(stage).to be_invalid
+        expect(stage.errors[:end_event_label]).to include("can't be blank")
+      end
+    end
+
+    context 'when group label is defined on the root group' do
+      it 'succeeds' do
+        stage = described_class.new({
+          name: 'My Stage',
+          parent: parent,
+          start_event_identifier: :issue_label_added,
+          start_event_label: group_label,
+          end_event_identifier: :issue_closed
+        })
+
+        expect(stage).to be_valid
+      end
+    end
+
+    context 'when subgroup is given' do
+      it 'succeeds' do
+        stage = described_class.new({
+          name: 'My Stage',
+          parent: parent_in_subgroup,
+          start_event_identifier: :issue_label_added,
+          start_event_label: group_label,
+          end_event_identifier: :issue_closed
+        })
+
+        expect(stage).to be_valid
+      end
+    end
+
+    context 'when label is defined for a different group' do
+      let(:error_message) { s_('CycleAnalyticsStage|is not available for the selected group') }
+
+      it 'returns validation for `start_event_label`' do
+        stage = described_class.new({
+          name: 'My Stage',
+          parent: parent_outside_of_group_label_scope,
+          start_event_identifier: :issue_label_added,
+          start_event_label: group_label,
+          end_event_identifier: :issue_closed
+        })
+
+        expect(stage).to be_invalid
+        expect(stage.errors[:start_event_label]).to include(error_message)
+      end
+
+      it 'returns validation for `end_event_label`' do
+        stage = described_class.new({
+          name: 'My Stage',
+          parent: parent_outside_of_group_label_scope,
+          start_event_identifier: :issue_closed,
+          end_event_identifier: :issue_label_added,
+          end_event_label: group_label
+        })
+
+        expect(stage).to be_invalid
+        expect(stage.errors[:end_event_label]).to include(error_message)
+      end
+    end
+
+    context 'when `ProjectLabel is given' do
+      let_it_be(:label) { create(:label) }
+
+      it 'raises error when `ProjectLabel` is given for `start_event_label`' do
+        params = {
+          name: 'My Stage',
+          parent: parent,
+          start_event_identifier: :issue_label_added,
+          start_event_label: label,
+          end_event_identifier: :issue_closed
+        }
+
+        expect { described_class.new(params) }.to raise_error(ActiveRecord::AssociationTypeMismatch)
+      end
+
+      it 'raises error when `ProjectLabel` is given for `end_event_label`' do
+        params = {
+          name: 'My Stage',
+          parent: parent,
+          start_event_identifier: :issue_closed,
+          end_event_identifier: :issue_label_added,
+          end_event_label: label
+        }
+
+        expect { described_class.new(params) }.to raise_error(ActiveRecord::AssociationTypeMismatch)
+      end
+    end
+  end
+end