1 files changed, 46 insertions, 0 deletions
diff --git a/spec/lib/gitlab/serializer/pagination_spec.rb b/spec/lib/gitlab/serializer/pagination_spec.rb
new file mode 100644
index 00000000000..43d9782c3b7
--- /dev/null
+++ b/spec/lib/gitlab/serializer/pagination_spec.rb
@@ -0,0 +1,46 @@
+require 'spec_helper'
+
+describe Gitlab::Serializer::Pagination do
+  let(:request) { spy('request') }
+  let(:response) { spy('response') }
+
+  before do
+    allow(request)
+      .to receive(:query_parameters)
+      .and_return(params)
+  end
+
+  let(:pagination) { described_class.new(request, response) }
+
+  describe '#paginate' do
+    subject { pagination.paginate(resource) }
+
+    let(:resource) { User.all }
+    let(:params) { { page: 1, per_page: 2 } }
+
+    context 'when a multiple resources are present in relation' do
+      before { create_list(:user, 3) }
+
+      it 'correctly paginates the resource' do
+        expect(subject.count).to be 2
+      end
+
+      it 'appends relevant headers' do
+        expect(response).to receive(:[]=).with('X-Total', '3')
+        expect(response).to receive(:[]=).with('X-Total-Pages', '2')
+        expect(response).to receive(:[]=).with('X-Per-Page', '2')
+
+        subject
+      end
+    end
+
+    context 'when an invalid resource is about to be paginated' do
+      let(:resource) { create(:user) }
+
+      it 'raises error' do
+        expect { subject }.to raise_error(
+          described_class::InvalidResourceError)
+      end
+    end
+  end
+end