require 'spec_helper' describe Gitlab::Serializer::Pagination do let(:request) { spy('request') } let(:response) { spy('response') } let(:headers) { spy('headers') } before do allow(request).to receive(:query_parameters) .and_return(params) allow(response).to receive(:headers) .and_return(headers) 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(headers).to receive(:[]=).with('X-Total', '3') expect(headers).to receive(:[]=).with('X-Total-Pages', '2') expect(headers).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