add spec

spec/factories/merge_requests.rb

@@ -73,6 +73,12 @@ FactoryGirl.define do
       merge_user author
     end
 
+    trait :remove_source_branch do
+      merge_params do
+        { 'force_remove_source_branch' => '1' }
+      end
+    end
+
     after(:build) do |merge_request|
       target_project = merge_request.target_project
       source_project = merge_request.source_project

spec/services/merge_requests/merge_service_spec.rb

@@ -185,7 +185,7 @@ describe MergeRequests::MergeService do
     context 'source branch removal' do
       context 'when the source branch is protected' do
         let(:service) do
-          described_class.new(project, user, should_remove_source_branch: '1')
+          described_class.new(project, user, 'should_remove_source_branch' => true)
         end
 
         before do
@@ -200,7 +200,7 @@ describe MergeRequests::MergeService do
 
       context 'when the source branch is the default branch' do
         let(:service) do
-          described_class.new(project, user, should_remove_source_branch: '1')
+          described_class.new(project, user, 'should_remove_source_branch' => true)
         end
 
         before do
@@ -215,10 +215,10 @@ describe MergeRequests::MergeService do
 
       context 'when the source branch can be removed' do
         context 'when MR author set the source branch to be removed' do
-          let(:service) do
-            merge_request.merge_params['force_remove_source_branch'] = '1'
-            merge_request.save!
-            described_class.new(project, user, commit_message: 'Awesome message')
+          let(:service) { described_class.new(project, user, commit_message: 'Awesome message') }
+
+          before do
+            merge_request.update_attribute(:merge_params, { 'force_remove_source_branch' => '1' })
           end
 
           it 'removes the source branch using the author user' do
@@ -227,11 +227,20 @@ describe MergeRequests::MergeService do
               .and_call_original
             service.execute(merge_request)
           end
+
+          context 'when the merger set the source branch not to be removed' do
+            let(:service) { described_class.new(project, user, commit_message: 'Awesome message', 'should_remove_source_branch' => false) }
+
+            it 'does not delete the source branch' do
+              expect(DeleteBranchService).not_to receive(:new)
+              service.execute(merge_request)
+            end
+          end
         end
 
         context 'when MR merger set the source branch to be removed' do
           let(:service) do
-            described_class.new(project, user, commit_message: 'Awesome message', should_remove_source_branch: '1')
+            described_class.new(project, user, commit_message: 'Awesome message', 'should_remove_source_branch' => true)
           end
 
           it 'removes the source branch using the current user' do