1 files changed, 73 insertions, 0 deletions
diff --git a/spec/requests/api/repositories_spec.rb b/spec/requests/api/repositories_spec.rb
index 6063afc213d..519638ebb82 100644
--- a/spec/requests/api/repositories_spec.rb
+++ b/spec/requests/api/repositories_spec.rb
@@ -465,4 +465,77 @@ describe API::Repositories do
       end
     end
   end
+
+  describe 'GET :id/repository/merge_base' do
+    let(:refs) do
+      %w(304d257dcb821665ab5110318fc58a007bd104ed 0031876facac3f2b2702a0e53a26e89939a42209)
+    end
+
+    subject(:request) do
+      get(api("/projects/#{project.id}/repository/merge_base", current_user), refs: refs)
+    end
+
+    shared_examples 'merge base' do
+      it 'returns the common ancestor' do
+        request
+
+        expect(response).to have_gitlab_http_status(:success)
+        expect(json_response['id']).to be_present
+      end
+    end
+
+    context 'when unauthenticated', 'and project is public' do
+      it_behaves_like 'merge base' do
+        let(:project) { create(:project, :public, :repository) }
+        let(:current_user) { nil }
+      end
+    end
+
+    context 'when unauthenticated', 'and project is private' do
+      it_behaves_like '404 response' do
+        let(:current_user) { nil }
+        let(:message) { '404 Project Not Found' }
+      end
+    end
+
+    context 'when authenticated', 'as a developer' do
+      it_behaves_like 'merge base' do
+        let(:current_user) { user }
+      end
+    end
+
+    context 'when authenticated', 'as a guest' do
+      it_behaves_like '403 response' do
+        let(:current_user) { guest }
+      end
+    end
+
+    context 'when passing refs that do not exist' do
+      it_behaves_like '400 response' do
+        let(:refs) { %w(304d257dcb821665ab5110318fc58a007bd104ed missing) }
+        let(:current_user) { user }
+        let(:message) { 'Could not find ref: missing' }
+      end
+    end
+
+    context 'when passing refs that do not have a merge base' do
+      it_behaves_like '404 response' do
+        let(:refs) { ['304d257dcb821665ab5110318fc58a007bd104ed', TestEnv::BRANCH_SHA['orphaned-branch']] }
+        let(:current_user) { user }
+        let(:message) { '404 Merge Base Not Found' }
+      end
+    end
+
+    context 'when not enough refs are passed' do
+      let(:refs) { %w(only-one) }
+      let(:current_user) { user }
+
+      it 'renders a bad request error' do
+        request
+
+        expect(response).to have_gitlab_http_status(:bad_request)
+        expect(json_response['message']).to eq('Provide exactly 2 refs')
+      end
+    end
+  end
 end