1 files changed, 22 insertions, 0 deletions
diff --git a/spec/services/merge_requests/merge_to_ref_service_spec.rb b/spec/services/merge_requests/merge_to_ref_service_spec.rb
index e2f201677fa..758679edc45 100644
--- a/spec/services/merge_requests/merge_to_ref_service_spec.rb
+++ b/spec/services/merge_requests/merge_to_ref_service_spec.rb
@@ -191,6 +191,28 @@ describe MergeRequests::MergeToRefService do
       it { expect(todo).not_to be_done }
     end
 
+    context 'when source is missing' do
+      it 'returns error' do
+        allow(merge_request).to receive(:diff_head_sha) { nil }
+
+        error_message = 'No source for merge'
+
+        result = service.execute(merge_request)
+
+        expect(result[:status]).to eq(:error)
+        expect(result[:message]).to eq(error_message)
+      end
+    end
+
+    context 'when target ref is passed as a parameter' do
+      let(:params) { { commit_message: 'merge train', target_ref: target_ref } }
+
+      it_behaves_like 'successfully merges to ref with merge method' do
+        let(:first_parent_ref) { 'refs/heads/master' }
+        let(:target_ref) { 'refs/merge-requests/1/train' }
+      end
+    end
+
     describe 'cascading merge refs' do
       set(:project) { create(:project, :repository) }
       let(:params) { { commit_message: 'Cascading merge', first_parent_ref: first_parent_ref, target_ref: target_ref } }