1 files changed, 72 insertions, 0 deletions
diff --git a/spec/services/external_pull_requests/create_pipeline_service_spec.rb b/spec/services/external_pull_requests/create_pipeline_service_spec.rb
new file mode 100644
index 00000000000..a4da5b38b97
--- /dev/null
+++ b/spec/services/external_pull_requests/create_pipeline_service_spec.rb
@@ -0,0 +1,72 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe ExternalPullRequests::CreatePipelineService do
+  describe '#execute' do
+    set(:project) { create(:project, :repository) }
+    set(:user) { create(:user) }
+    let(:pull_request) { create(:external_pull_request, project: project) }
+
+    before do
+      project.add_maintainer(user)
+    end
+
+    subject { described_class.new(project, user).execute(pull_request) }
+
+    context 'when pull request is open' do
+      before do
+        pull_request.update!(status: :open)
+      end
+
+      context 'when source sha is the head of the source branch' do
+        let(:source_branch) { project.repository.branches.last }
+        let(:create_pipeline_service) { instance_double(Ci::CreatePipelineService) }
+
+        before do
+          pull_request.update!(source_branch: source_branch.name, source_sha: source_branch.target)
+        end
+
+        it 'creates a pipeline for external pull request' do
+          expect(subject).to be_valid
+          expect(subject).to be_persisted
+          expect(subject).to be_external_pull_request_event
+          expect(subject).to eq(project.ci_pipelines.last)
+          expect(subject.external_pull_request).to eq(pull_request)
+          expect(subject.user).to eq(user)
+          expect(subject.status).to eq('pending')
+          expect(subject.ref).to eq(pull_request.source_branch)
+          expect(subject.sha).to eq(pull_request.source_sha)
+          expect(subject.source_sha).to eq(pull_request.source_sha)
+        end
+      end
+
+      context 'when source sha is not the head of the source branch (force push upon rebase)' do
+        let(:source_branch) { project.repository.branches.first }
+        let(:commit) { project.repository.commits(source_branch.name, limit: 2).last }
+
+        before do
+          pull_request.update!(source_branch: source_branch.name, source_sha: commit.sha)
+        end
+
+        it 'does nothing' do
+          expect(Ci::CreatePipelineService).not_to receive(:new)
+
+          expect(subject).to be_nil
+        end
+      end
+    end
+
+    context 'when pull request is not opened' do
+      before do
+        pull_request.update!(status: :closed)
+      end
+
+      it 'does nothing' do
+        expect(Ci::CreatePipelineService).not_to receive(:new)
+
+        expect(subject).to be_nil
+      end
+    end
+  end
+end