require 'spec_helper' describe API::Helpers::Pagination do let(:resource) { Project.all } subject do Class.new.include(described_class).new end describe '#paginate' do let(:value) { spy('return value') } before do allow(value).to receive(:to_query).and_return(value) allow(subject).to receive(:header).and_return(value) allow(subject).to receive(:params).and_return(value) allow(subject).to receive(:request).and_return(value) end describe 'required instance methods' do let(:return_spy) { spy } it 'requires some instance methods' do expect_message(:header) expect_message(:params) expect_message(:request) subject.paginate(resource) end end context 'when resource can be paginated' do before do create_list(:project, 3) end describe 'first page' do before do allow(subject).to receive(:params) .and_return({ page: 1, per_page: 2 }) end it 'returns appropriate amount of resources' do expect(subject.paginate(resource).count).to eq 2 end it 'adds appropriate headers' do expect_header('X-Total', '3') expect_header('X-Total-Pages', '2') expect_header('X-Per-Page', '2') expect_header('X-Page', '1') expect_header('X-Next-Page', '2') expect_header('X-Prev-Page', '') expect_header('Link', anything) do |_key, val| expect(val).to include('rel="first"') expect(val).to include('rel="last"') expect(val).to include('rel="next"') expect(val).not_to include('rel="prev"') end subject.paginate(resource) end end describe 'second page' do before do allow(subject).to receive(:params) .and_return({ page: 2, per_page: 2 }) end it 'returns appropriate amount of resources' do expect(subject.paginate(resource).count).to eq 1 end it 'adds appropriate headers' do expect_header('X-Total', '3') expect_header('X-Total-Pages', '2') expect_header('X-Per-Page', '2') expect_header('X-Page', '2') expect_header('X-Next-Page', '') expect_header('X-Prev-Page', '1') expect_header('Link', anything) do |_key, val| expect(val).to include('rel="first"') expect(val).to include('rel="last"') expect(val).to include('rel="prev"') expect(val).not_to include('rel="next"') end subject.paginate(resource) end end end context 'when resource empty' do describe 'first page' do before do allow(subject).to receive(:params) .and_return({ page: 1, per_page: 2 }) end it 'returns appropriate amount of resources' do expect(subject.paginate(resource).count).to eq 0 end it 'adds appropriate headers' do expect_header('X-Total', '0') expect_header('X-Total-Pages', '1') expect_header('X-Per-Page', '2') expect_header('X-Page', '1') expect_header('X-Next-Page', '') expect_header('X-Prev-Page', '') expect_header('Link', anything) do |_key, val| expect(val).to include('rel="first"') expect(val).to include('rel="last"') expect(val).not_to include('rel="prev"') expect(val).not_to include('rel="next"') expect(val).not_to include('page=0') end subject.paginate(resource) end end end def expect_header(*args, &block) expect(subject).to receive(:header).with(*args, &block) end def expect_message(method) expect(subject).to receive(method) .at_least(:once).and_return(value) end end end