Testing Services with Pact

Integration testing services is hard but critical to ensure all your internal APIs conform, do not break their consumers but only provide the minimum required.

Pact's (https://github.com/realestate-com-au/pact) implementation of consumer driven contracts goes a long way to solving these issues.

Transcript

1. Testing services with PACT
2. Gabriel Rotbart Developer @ Hooroo @gabrielrotbart
3. why?
4. why? … am I presenting this
5. Consumer [noun]: The  thing  that  sends  a  specific   request  to  a  specific  end  point   for  a  response  in  a  specific   format
6. Provider [noun]: The  thing  that  gets  asked  for   stuff  and  provides  the  agreed   stuff  in  an  agreed  format
7. Separate services
8. Separate services = Separate Tests
9. Separate Tests = Separate Feedback loops
10. confidence vs effort
11. Meaningful tests across services
12. Consumer Driven Contracts
13. Pact github.com/realestate-­‐com-­‐au/pact Beth  Skurrie  (bethesque)  and  co.
14. Pact Specify  a  contract  during   consumer  testing Generates  tests  that  verify   the  contract  during  provider   testing
15. flow Consumer Provider Specify an API in spec Make spec green Implement API contract by making spec green
16. Consumer Provider
17. Round one: consumer speccing describe  FeedMeService  do   describe  ‘asking  fat  man  for  food’  do   it  'he  provides  (or  dies)'  do   end   end   end
18. Round one: consumer speccing before  do    fat_man_api   .upon_receiving("a  request  to  feed  me”)   .with(   method:  :get,   path:  ‘/feed',   query:  {   food:'My  favourite  food’,   who:  ‘stewie'   }   ).will_respond_with(   status:  200,   headers:  {  'Content-­‐Type'  =>  ‘application/json  },   body:  {  food:  "Scooby-­‐Doo  yogurt"  }    )   end
19. Round one: consumer speccing fat_man_api   .upon_receiving("a  request  to  feed  me”)   .with(   method:  :get,   path:  ‘/feed',   query:  {   food:'My  favourite  food’,   who:  ‘stewie'   }   ).will_respond_with(   status:  200,   headers:  {  'Content-­‐Type'  =>  ‘application/json  },   body:  {  food:  "Scooby-­‐Doo  yogurt"  }    )
20. Round one: consumer speccing fat_man_api   .upon_receiving("a  request  to  feed  me”)   .with(   method:  :get,   path:  ‘/feed',   query:  {   food:'My  favourite  food’,   who:  ‘stewie'   }   ).will_respond_with(   status:  200,   headers:  {  'Content-­‐Type'  =>  ‘application/json  },   body:  {  food:  "Scooby-­‐Doo  yogurt"  }    )
21. Round one: consumer speccing fat_man_api   .upon_receiving("a  request  to  feed  me”)   .with(   method:  :get,   path:  ‘/feed',   query:  {   food:'My  favourite  food’,   who:  ‘stewie'   }   ).will_respond_with(   status:  200,   headers:  {  'Content-­‐Type'  =>  ‘application/json  },   body:  {  food:  "Scooby-­‐Doo  yogurt"  }    )
22. Round one: consumer speccing .with(   method:  :post,   path:  ‘/invent’,   body:  {   invention:  ‘Death  Ray’   }
23. Round one: consumer speccing .with(   method:  :delete,   path:  ‘/all_humans’
24. Round one: consumer speccing fat_man_api   .upon_receiving("a  request  to  feed  me”)   .with(   method:  :get,   path:  ‘/feed',   query:  {   food:'My  favourite  food’,   who:  ‘stewie'   }   ).will_respond_with(   status:  200,   headers:  {  'Content-­‐Type'  =>  ‘application/json  },   body:  {  food:  "Scooby-­‐Doo  yogurt"  }    )
25. Round one: consumer speccing it  'he  provides  (or  dies)'  do   food  =  FeedMeService.ask_fat_man_for('My  favourite  food')   expect(food).to  eq({  'food'  =>  "Scooby-­‐Doo  yogurt  with   Shaggy's  eyes  scratched  out"  })             end
26. Round one:Mock Service Consumer Mock service (Fat Man) GET  /feed?food=… When  (GET  /feed…)   received Respond  with   {  food:  …  } {  food:  …  }
27. Round one point five: JSON file { "consumer": { "name": "Stewie" }, "provider": { "name": "Fat man" }, "interactions": [ { "description": "a request to feed me", "request": { "method": "get", "path": "/feed", "query": "food=My%20favourite%20food&who=stewie" }, "response": { "status": 200, "headers": { "Content-Type": "application/json; charset=utf-8" }, "body": { "food": "Scooby-Doo yogurt with Shaggy's" } } } ], "metadata": { "pactSpecificationVersion": "1.0.0" } }
28. Round Two: Provider verifying Pact.service_provider  “Fat  Man"  do      honours_pact_with  'Stewie'  do          pact_uri  ‘~/stewie/spec/pacts/stewie-­‐fat_man.json’      end   end
29. Round Two: Provider verifying auto generated tests it  ‘returns  200’  do { "consumer": { "name": "Stewie" }, "provider": { "name": "Fat man" }, "interactions": [ { "description": "a request to feed me", "request": { "method": "get", "path": "/feed", "query": "food=My%20favourite%20food&who=stewie" }, "response": { "status": 200, "headers": { "Content-Type": "application/json; charset=utf-8" }, "body": { "food": "Scooby-Doo yogurt with Shaggy's" } } } ], "metadata": { "pactSpecificationVersion": "1.0.0" } } GET  /feed?food=… expect   (response.status)   .to  eq(200) end Provider
30. Round Two: Provider verifying Verifying  a  pact  between  Stewie  and  Fat  man      A  request  to  feed  me          with  GET  /feed?food=My  favourite  food&who=stewie              returns  a  response  which                  has  status  code  200  (FAILED  -­‐  1)                  has  a  matching  body  (FAILED  -­‐  2)                  includes  headers                      "Content-­‐Type"  with  value  "application/ json"  (FAILED  -­‐  3)
31. Round Two: Provider verifying return  render  nothing:  true,     status:  :not_found  if  params[:who]  ==  'meg'   if  params[:who]  ==  'stewie'  &&  params[:food]  ==  URI.decode('My   favourite  food’)   return  render  json:  {  food:  "Scooby-­‐Doo  yogurt  with  Shaggy's   eyes  scratched  out"  }   end
32. Round Two: Provider verifying return  render  nothing:  true,     status:  :not_found  if  params[:who]  ==  'meg'   if  params[:who]  ==  'stewie'  &&  params[:food]  ==  URI.decode('My   favourite  food’)   return  render  json:  {  food:  "Scooby-­‐Doo  yogurt  with  Shaggy's   eyes  scratched  out"  }   end For Demonstration Only
33. Round Two: Provider verifying Verifying  a  pact  between  Stewie  and  Fat  man      A  request  to  feed  me          with  GET  /feed?food=My  favourite  food&who=stewie              returns  a  response  which                  has  status  code  200                  has  a  matching  body                  includes  headers                      "Content-­‐Type"  with  value  “application/json"
34. Source of Truth
35. Changes with the api
36. A  B A B
37. A  B C  D A B C D
38. A  B C  D A B C D
39. C  D A C D
40. Works 99% better*
41. small doses
42. If it is hard to test…
43. Debug
44. Build system with multiple services
45. s3
46. Pact Broker github.com/bethesque/pact_broker
47. Qs martinfowler.com/articles/ consumerDrivenContracts.html