Render MR commit SHA instead "diffs" when viable

1 files changed, 35 insertions, 0 deletions

diff --git a/spec/lib/banzai/filter/merge_request_reference_filter_spec.rb b/spec/lib/banzai/filter/merge_request_reference_filter_spec.rb
index eeb82822f68..a1dd72c498f 100644
--- a/spec/lib/banzai/filter/merge_request_reference_filter_spec.rb
+++ b/spec/lib/banzai/filter/merge_request_reference_filter_spec.rb
@@ -196,6 +196,41 @@ describe Banzai::Filter::MergeRequestReferenceFilter do
     end
   end
 
+  context 'URL reference for a commit' do
+    let(:mr) { create(:merge_request, :with_diffs) }
+    let(:reference) do
+      urls.project_merge_request_url(mr.project, mr) + "/diffs?commit_id=#{mr.diff_head_sha}"
+    end
+    let(:commit) { mr.commits.find { |commit| commit.sha == mr.diff_head_sha } }
+
+    it 'links to a valid reference' do
+      doc = reference_filter("See #{reference}")
+
+      expect(doc.css('a').first.attr('href'))
+        .to eq reference
+    end
+
+    it 'has valid text' do
+      doc = reference_filter("See #{reference}")
+
+      expect(doc.text).to eq("See #{mr.to_reference(full: true)} (#{commit.short_id})")
+    end
+
+    it 'has valid title attribute' do
+      doc = reference_filter("See #{reference}")
+
+      expect(doc.css('a').first.attr('title')).to eq(commit.title)
+    end
+
+    it 'ignores invalid commit short_ids on link text' do
+      invalidate_commit_reference =
+        urls.project_merge_request_url(mr.project, mr) + "/diffs?commit_id=12345678"
+      doc = reference_filter("See #{invalidate_commit_reference}")
+
+      expect(doc.text).to eq("See #{mr.to_reference(full: true)} (diffs)")
+    end
+  end
+
   context 'cross-project URL reference' do
     let(:namespace) { create(:namespace, name: 'cross-reference') }
     let(:project2)  { create(:project, :public, namespace: namespace) }