Also test against external-issue for deleted projects

This is based on:

https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/10841

spec/lib/banzai/redactor_spec.rb

@@ -43,12 +43,24 @@ describe Banzai::Redactor do
     end
 
     context 'when project is in pending delete' do
+      let!(:issue) { create(:issue, project: project) }
+      let(:redactor) { described_class.new(project, user) }
+
+      before do
+        project.update(pending_delete: true)
+      end
+
       it 'redacts an issue attached' do
-        project.pending_delete = true
-        project.save
-        issue = create(:issue, project: project)
-        redactor = described_class.new(project, user)
-        doc = Nokogiri::HTML.fragment("<a class='gfm' data-reference-type='issue' data-project=\"#{project.id}\" data-issue=\"#{issue.id}\">foo</a>")
+        doc = Nokogiri::HTML.fragment("<a class='gfm' data-reference-type='issue' data-issue='#{issue.id}'>foo</a>")
+
+        redactor.redact([doc])
+
+        expect(doc.to_html).to eq('foo')
+      end
+
+      it 'redacts an external issue' do
+        doc = Nokogiri::HTML.fragment("<a class='gfm' data-reference-type='issue' data-external-issue='#{issue.id}' data-project='#{project.id}'>foo</a>")
+
         redactor.redact([doc])
 
         expect(doc.to_html).to eq('foo')