Allow a user to select `allow maintainer to push`

When a project is not private, and the source branch not protected the
user can now select the option to allow maintainers to push to this
branch

1 files changed, 37 insertions, 0 deletions

diff --git a/spec/services/merge_requests/update_service_spec.rb b/spec/services/merge_requests/update_service_spec.rb
index c31259239ee..5279ea6164e 100644
--- a/spec/services/merge_requests/update_service_spec.rb
+++ b/spec/services/merge_requests/update_service_spec.rb
@@ -1,6 +1,8 @@
 require 'spec_helper'
 
 describe MergeRequests::UpdateService, :mailer do
+  include ProjectForksHelper
+
   let(:project) { create(:project, :repository) }
   let(:user) { create(:user) }
   let(:user2) { create(:user) }
@@ -538,5 +540,40 @@ describe MergeRequests::UpdateService, :mailer do
       let(:open_issuable) { merge_request }
       let(:closed_issuable) { create(:closed_merge_request, source_project: project) }
     end
+
+    context 'setting `allow_maintainer_to_push`' do
+      let(:target_project) { create(:project, :public) }
+      let(:source_project) { fork_project(target_project) }
+      let(:user) { create(:user) }
+      let(:merge_request) do
+        create(:merge_request,
+               source_project: source_project,
+               source_branch: 'fixes',
+               target_project: target_project)
+      end
+
+      before do
+        allow(ProtectedBranch).to receive(:protected?).with(source_project, 'fixes') { false }
+      end
+
+      it 'does not allow a maintainer of the target project to set `allow_maintainer_to_push`' do
+        target_project.add_developer(user)
+
+        update_merge_request(allow_maintainer_to_push: true, title: 'Updated title')
+
+        expect(merge_request.title).to eq('Updated title')
+        expect(merge_request.allow_maintainer_to_push).to be_falsy
+      end
+
+      it 'is allowed by a user that can push to the source and can update the merge request' do
+        merge_request.update!(assignee: user)
+        source_project.add_developer(user)
+
+        update_merge_request(allow_maintainer_to_push: true, title: 'Updated title')
+
+        expect(merge_request.title).to eq('Updated title')
+        expect(merge_request.allow_maintainer_to_push).to be_truthy
+      end
+    end
   end
 end