1 files changed, 24 insertions, 0 deletions
diff --git a/spec/models/concerns/discussion_on_diff_spec.rb b/spec/models/concerns/discussion_on_diff_spec.rb
new file mode 100644
index 00000000000..0002a00770f
--- /dev/null
+++ b/spec/models/concerns/discussion_on_diff_spec.rb
@@ -0,0 +1,24 @@
+require 'spec_helper'
+
+describe DiffDiscussion, DiscussionOnDiff, model: true do
+  subject { create(:diff_note_on_merge_request).to_discussion }
+
+  describe "#truncated_diff_lines" do
+    let(:truncated_lines) { subject.truncated_diff_lines }
+
+    context "when diff is greater than allowed number of truncated diff lines " do
+      it "returns fewer lines"  do
+        expect(subject.diff_lines.count).to be > described_class::NUMBER_OF_TRUNCATED_DIFF_LINES
+
+        expect(truncated_lines.count).to be <= described_class::NUMBER_OF_TRUNCATED_DIFF_LINES
+      end
+    end
+
+    context "when some diff lines are meta" do
+      it "returns no meta lines"  do
+        expect(subject.diff_lines).to include(be_meta)
+        expect(truncated_lines).not_to include(be_meta)
+      end
+    end
+  end
+end