Property Based Integration Testing in Ruby Trevor Brown 

Trevor Brown Sarasota, Fl JavaScript, Erlang, Elixir, Ruby Software Developer at RentPath @Stratus3D Github.com/Stratus3D [email protected] 

Property Based Testing 

Property Based Testing “Property based testing is the construction of tests such that, when these tests are fuzzed, failures in the test reveal problems with the system under test…” – https://hypothesis.works/articles/what-is-property- based-testing/ 

Integration Testing "Integration testing (sometimes called integration and testing, abbreviated I&T) is the phase in software testing in which individual software modules are combined and tested as a group." – https://en.wikipedia.org/wiki/Integration_testing 

Integration Testing Limitations • Integration testing becomes difficult when – You do not control part or all of the system – You cannot control the data in the system – The system is in production 

Property Based Integration Tests • Integration tests • Use generators instead of hardcoded values • Generators are combined to produce numerous test cases 

describe '/v3/cities' do let(:url) { '/v3/cities' } it "returns a list of cities" do params = { state: 'california', limit: 10 } get url, params # It was a success expect(last_response.status).to eq(200) # Has the expected structure expect(json_body).to be_a(Array) # Has the expected number of results expect(json_body.count).to be >= 0 expect(json_body.count).to be <= 10 # Results have the expected fields json_body.each do |record| expect(record.keys.sort).to eq(%w(name state url)) end # Results are sorted properly if json_body.first and json_body.second expect(json_body.first['name']).to be < json_body.second['name'] end end end 

describe '/v3/cities' do it "returns a list of cities" do property_of do state = choose(*states) limit = range(0, 25) [state, limit] end.check do |(state, limit)| params = { state: space_to_dash(state), limit: limit } get url, params # It was a success expect(last_response.status).to eq(200) # Has the expected structure expect(json_body).to be_a(Array) # Has the expected number of results expect(json_body.count).to be >= 0 expect(json_body.count).to be <= limit # Results have the expected fields json_body.each do |record| expect(record.keys.sort).to eq(%w(name state url)) end # Results are sorted properly if json_body.first and json_body.second expect(json_body.first['name']).to be < json_body.second['name'] end end end end 

Trevor Brown @Stratus3D Github.com/Stratus3D [email protected] ● https://speakerdeck.com/stratus3d/property-based-integration-testing-in-ruby ● https://www.youtube.com/watch?v=OVLTHGaTi7k ● http://blog.jessitron.com/2014/09/tdd-with-generative-testing-example-in.html ● https://www.sitepoint.com/the-how-and-why-of-property-based-testing-in-ruby/