Addressed review suggestions

Abstracted jira check functionality to project
instance method.
Tabulated specs

ee/app/models/ee/project.rb

@@ -770,6 +770,12 @@ module EE
       end
     end
 
+    def prevent_merge_without_jira_issue?
+      return false unless jira_issue_association_required_to_merge_enabled?
+
+      prevent_merge_without_jira_issue
+    end
+
     private
 
     def group_hooks

ee/app/services/ee/merge_requests/merge_base_service.rb

@@ -64,8 +64,7 @@ module EE
       end
 
       def check_jira_issue_enforcement
-        return unless merge_request.project.jira_issue_association_required_to_merge_enabled?
-        return unless merge_request.project.prevent_merge_without_jira_issue
+        return unless merge_request.project.prevent_merge_without_jira_issue?
         return if Atlassian::JiraIssueKeyExtractor.has_keys?(merge_request.title, merge_request.description)
 
         raise ::MergeRequests::MergeService::MergeError, _('Before this can be merged, a Jira issue must be linked in the title or description')

ee/spec/models/project_spec.rb

@@ -2733,6 +2733,28 @@ RSpec.describe Project do
     end
   end
 
+  describe '#prevent_merge_without_jira_issue?' do
+    using RSpec::Parameterized::TableSyntax
+
+    subject { project.prevent_merge_without_jira_issue? }
+
+    where(:feature_available, :prevent_merge, :result) do
+      true  | true  | true
+      true  | false | false
+      false | true  | false
+      false | false | false
+    end
+
+    with_them do
+      before do
+        allow(project).to receive(:jira_issue_association_required_to_merge_enabled?).and_return(feature_available)
+        project.create_project_setting(prevent_merge_without_jira_issue: prevent_merge)
+      end
+
+      it { is_expected.to be result }
+    end
+  end
+
   context 'indexing updates in Elasticsearch', :elastic do
     before do
       stub_ee_application_setting(elasticsearch_indexing: true)

ee/spec/services/merge_requests/merge_service_spec.rb

@@ -44,74 +44,35 @@ RSpec.describe MergeRequests::MergeService do
       end
     end
 
-    context 'jira issue enforcement' do
+    context 'with jira issue enforcement' do
+      using RSpec::Parameterized::TableSyntax
+
       subject do
         perform_enqueued_jobs do
           service.execute(merge_request)
         end
       end
 
-      shared_examples 'merges the MR with no error' do
-        it do
-          subject
-
-          expect(merge_request.reload.merged?).to eq(true)
-        end
+      where(:prevent_merge, :issue_specified, :merged) do
+        true  | true  | true
+        true  | false | false
+        false | true  | true
+        false | false | true
       end
 
-      context 'when feature is available' do
+      with_them do
         before do
-          stub_licensed_features(jira_issue_association_enforcement: true)
-          stub_feature_flags(jira_issue_association_on_merge_request: true)
-        end
-
-        context 'when jira issue is required for merge' do
-          before do
-            project.create_project_setting(prevent_merge_without_jira_issue: true)
-          end
-
-          context 'when issue key is NOT specified in MR title / description' do
-            it 'returns appropriate merge error' do
-              subject
-
-              expect(merge_request.merge_error).to include('Before this can be merged, a Jira issue must be linked in the title or description')
-            end
-          end
-
-          context 'when issue key is specified in MR title / description' do
-            before do
-              merge_request.update!(title: "Fixes login issue SECURITY-1234")
-            end
-
-            it_behaves_like 'merges the MR with no error'
-          end
+          allow(project).to receive(:prevent_merge_without_jira_issue?).and_return(prevent_merge)
+          allow(Atlassian::JiraIssueKeyExtractor).to receive(:has_keys?)
+                                                       .with(merge_request.title, merge_request.description)
+                                                       .and_return(issue_specified)
         end
 
-        context 'when jira issue is NOT required for merge' do
-          before do
-            project.create_project_setting(prevent_merge_without_jira_issue: false)
-          end
-
-          it_behaves_like 'merges the MR with no error'
-        end
-      end
-
-      context 'when feature is NOT available' do
-        using RSpec::Parameterized::TableSyntax
-
-        where(:licensed, :feature_flag) do
-          false | true
-          true  | false
-          false | false
-        end
-
-        with_them do
-          before do
-            stub_licensed_features(jira_issue_association_enforcement: licensed)
-            stub_feature_flags(jira_issue_association_on_merge_request: feature_flag)
-          end
+        it 'sets the correct merged state and raises an error when applicable', :aggregate_failures do
+          subject
 
-          it_behaves_like 'merges the MR with no error'
+          expect(merge_request.reload.merged?).to eq(merged)
+          expect(merge_request.merge_error).to include('Before this can be merged, a Jira issue must be linked in the title or description') unless merged
         end
       end
     end