4 files changed, 67 insertions, 0 deletions
diff --git a/spec/fixtures/api/schemas/entities/diff_line.json b/spec/fixtures/api/schemas/entities/diff_line.json
new file mode 100644
index 00000000000..66e8b443e1b
--- /dev/null
+++ b/spec/fixtures/api/schemas/entities/diff_line.json
@@ -0,0 +1,14 @@
+{
+  "type": "object",
+  "required": ["type"],
+  "properties": {
+    "line_code": { "type": ["string", "null"] },
+    "type": { "type": ["string", "null"] },
+    "old_line": { "type": ["integer", "null"] },
+    "new_line": { "type": ["integer", "null"] },
+    "text": { "type": ["string"] },
+    "rich_text": { "type": ["string"] },
+    "meta_data": { "type": ["object", "null"] }
+  },
+  "additionalProperties": false
+}
diff --git a/spec/fixtures/api/schemas/entities/diff_line_parallel.json b/spec/fixtures/api/schemas/entities/diff_line_parallel.json
new file mode 100644
index 00000000000..f924eb0c601
--- /dev/null
+++ b/spec/fixtures/api/schemas/entities/diff_line_parallel.json
@@ -0,0 +1,11 @@
+{
+  "required" : [
+    "left",
+    "right"
+  ],
+  "properties" : {
+    "left": { "$ref": "diff_line.json" },
+    "right": { "$ref": "diff_line.json" }
+  },
+  "additionalProperties": false
+}
diff --git a/spec/serializers/diff_file_entity_spec.rb b/spec/serializers/diff_file_entity_spec.rb
index 00b2146dc86..3d90ce44dfb 100644
--- a/spec/serializers/diff_file_entity_spec.rb
+++ b/spec/serializers/diff_file_entity_spec.rb
@@ -67,4 +67,21 @@ describe DiffFileEntity do
       end
     end
   end
+
+  context '#parallel_diff_lines' do
+    it 'exposes parallel diff lines correctly' do
+      response = subject
+
+      lines = response[:parallel_diff_lines]
+
+      # make sure at least one line is present for each side
+      expect(lines.map { |line| line[:right] }.compact).to be_present
+      expect(lines.map { |line| line[:left] }.compact).to be_present
+      # make sure all lines are in correct format
+      lines.each do |parallel_line|
+        expect(parallel_line[:left].as_json).to match_schema('entities/diff_line') if parallel_line[:left]
+        expect(parallel_line[:right].as_json).to match_schema('entities/diff_line') if parallel_line[:right]
+      end
+    end
+  end
 end
diff --git a/spec/serializers/diff_line_serializer_spec.rb b/spec/serializers/diff_line_serializer_spec.rb
new file mode 100644
index 00000000000..6dd8abd0579
--- /dev/null
+++ b/spec/serializers/diff_line_serializer_spec.rb
@@ -0,0 +1,25 @@
+require 'spec_helper'
+
+describe DiffLineSerializer do
+  let(:line) { Gitlab::Diff::Line.new('hello world', 'new', 1, nil, 1) }
+  let(:serializer) { described_class.new.represent(line) }
+
+  describe '#to_json' do
+    subject { serializer.to_json }
+
+    it 'matches the schema' do
+      expect(subject).to match_schema('entities/diff_line')
+    end
+
+    context 'when lines are parallel' do
+      let(:right_line) { Gitlab::Diff::Line.new('right line', 'new', 1, nil, 1) }
+      let(:left_line) { Gitlab::Diff::Line.new('left line', 'match', 1, nil, 1) }
+      let(:parallel_line) { [{ right: right_line, left: left_line }] }
+      let(:serializer) { described_class.new.represent(parallel_line, {}, DiffLineParallelEntity) }
+
+      it 'matches the schema' do
+        expect(subject).to match_schema('entities/diff_line_parallel')
+      end
+    end
+  end
+end