2 files changed, 24 insertions, 0 deletions
diff --git a/spec/serializers/diff_file_entity_spec.rb b/spec/serializers/diff_file_entity_spec.rb
index 3d90ce44dfb..7497b8f27bd 100644
--- a/spec/serializers/diff_file_entity_spec.rb
+++ b/spec/serializers/diff_file_entity_spec.rb
@@ -26,6 +26,11 @@ describe DiffFileEntity do
       )
     end
 
+    it 'includes viewer' do
+      expect(subject[:viewer].with_indifferent_access)
+          .to match_schema('entities/diff_viewer')
+    end
+
     # Converted diff files from GitHub import does not contain blob file
     # and content sha.
     context 'when diff file does not have a blob and content sha' do
diff --git a/spec/serializers/diff_viewer_entity_spec.rb b/spec/serializers/diff_viewer_entity_spec.rb
new file mode 100644
index 00000000000..66ac6ef2adc
--- /dev/null
+++ b/spec/serializers/diff_viewer_entity_spec.rb
@@ -0,0 +1,19 @@
+require 'spec_helper'
+
+describe DiffViewerEntity do
+  include RepoHelpers
+
+  let(:project) { create(:project, :repository) }
+  let(:repository) { project.repository }
+  let(:commit) { project.commit(sample_commit.id) }
+  let(:diff_refs) { commit.diff_refs }
+  let(:diff) { commit.raw_diffs.first }
+  let(:diff_file) { Gitlab::Diff::File.new(diff, diff_refs: diff_refs, repository: repository) }
+  let(:viewer) { diff_file.simple_viewer }
+
+  subject { described_class.new(viewer).as_json }
+
+  it 'serializes diff file viewer' do
+    expect(subject.with_indifferent_access).to match_schema('entities/diff_viewer')
+  end
+end