1 files changed, 31 insertions, 1 deletions
diff --git a/spec/services/merge_requests/build_service_spec.rb b/spec/services/merge_requests/build_service_spec.rb
index b46c419de14..fee293760f5 100644
--- a/spec/services/merge_requests/build_service_spec.rb
+++ b/spec/services/merge_requests/build_service_spec.rb
@@ -29,13 +29,27 @@ describe MergeRequests::BuildService do
 
   before do
     project.team << [user, :guest]
+  end
 
+  def stub_compare
     allow(CompareService).to receive_message_chain(:new, :execute).and_return(compare)
     allow(project).to receive(:commit).and_return(commit_1)
     allow(project).to receive(:commit).and_return(commit_2)
   end
 
-  describe 'execute' do
+  describe '#execute' do
+    it 'calls the compare service with the correct arguments' do
+      expect(CompareService).to receive(:new)
+                                  .with(project, Gitlab::Git::BRANCH_REF_PREFIX + source_branch)
+                                  .and_call_original
+
+      expect_any_instance_of(CompareService).to receive(:execute)
+                                                  .with(project, Gitlab::Git::BRANCH_REF_PREFIX + target_branch)
+                                                  .and_call_original
+
+      merge_request
+    end
+
     context 'missing source branch' do
       let(:source_branch) { '' }
 
@@ -52,6 +66,10 @@ describe MergeRequests::BuildService do
       let(:target_branch) { nil }
       let(:commits) { Commit.decorate([commit_1], project) }
 
+      before do
+        stub_compare
+      end
+
       it 'creates compare object with target branch as default branch' do
         expect(merge_request.compare).to be_present
         expect(merge_request.target_branch).to eq(project.default_branch)
@@ -77,6 +95,10 @@ describe MergeRequests::BuildService do
     context 'no commits in the diff' do
       let(:commits) { [] }
 
+      before do
+        stub_compare
+      end
+
       it 'allows the merge request to be created' do
         expect(merge_request.can_be_created).to eq(true)
       end
@@ -89,6 +111,10 @@ describe MergeRequests::BuildService do
     context 'one commit in the diff' do
       let(:commits) { Commit.decorate([commit_1], project) }
 
+      before do
+        stub_compare
+      end
+
       it 'allows the merge request to be created' do
         expect(merge_request.can_be_created).to eq(true)
       end
@@ -149,6 +175,10 @@ describe MergeRequests::BuildService do
     context 'more than one commit in the diff' do
       let(:commits) { Commit.decorate([commit_1, commit_2], project) }
 
+      before do
+        stub_compare
+      end
+
       it 'allows the merge request to be created' do
         expect(merge_request.can_be_created).to eq(true)
       end