How To Build a Test Lib for a Microservice Based Web Application with Geb & Spock

At REWE digital we are building & maintaining a Microservice based e-commerce web application. Our service teams work quite autonomous & are responsible for their own services' quality. They decide which measures are appropriate & efficient in order ensure no bugs in production. Many have a reasonable code coverage via unit tests, a good lot of service tests –including UI tests– & a sufficient monitoring & alerting system.

However, several teams felt the need for a more integrated testing of the whole system to prevent CSS clashes, errors due to interface changes or eventual inconsistency disasters & many many unforeseen issues.

To support these teams, we decided turn our old retired comprehensive test suite into a test library to enable teams to write their own system tests without the need to implement every stupid step in every team.

In this talk I'd like to present our lessons learned & developed design patterns from implementing such a test library with Geb & Spock.

Demo from slide 15: https://youtu.be/JszqevCoCts
Demo from slide 19: https://youtu.be/SaDUQk3Ov8I

Transcript

1. @MichaKutz
   @rewedigital
   @greachconf
   How to Build a Test Library
   for a Microservices-Based Web
   Application
   with Geb & Spock
   Kopenhagen, May 28th 2019
   

   View Slide

2. @MichaKutz
   @rewedigital
   @greachconf
   

   View Slide

3. What’s the challenge ?
   

   View Slide

4. > 25 teams
   > 150
   services
   composition of
   micro-frontends
   deployment
   at will
   

   View Slide

5. View Slide

6. Simple unit tests
   are easy
   Testing a single service is easy…
   but contract tests are hard due to
   asynchronous communication
   Fully integrated system tests seem
   necessary, but are hard
   ⇒ not done by most teams
   Requires a test system
   Requires a built service
   Requires code only
   

   View Slide

7. Each team writes functional test
   that matter most to them
   Test suite grows
   bigger and bigger…
   …test runs take longer
   and longer
   Nobody is responsible for the
   suite as a whole
   …up to 3 hours!!!
   No team wants it in its
   delivery pipeline
   

   View Slide

8. Page Objects for
   every relevant page
   Further code to
   navigate around the
   application
   Base test class
   for basic test setup
   Test environment
   configuration
   Test fixtures
   (accounts, products,
   addresses)
   Geb configuration for
   needed browsers
   “Hacks” to
   manipulate the
   application
   

   View Slide

9. How does it work ?
   

   View Slide

10. class DemoSpec extends ReweShopSpec {
    ShopUserActor user = new ShopUserActor(browser, reweConfig)
    .withPickupMarketSelected()
    .withInvoiceAddress(Address.COLOGNE)
    .withRegistered()
    .withLoggedIn()
    .withWindowSize(1280, 768)
    def "fill basket"() {
    given:
    ShopPage shopPage = user.to(ShopPage)
    shopPage.searchFor("milch")
    when:
    shopPage.searchSuggestions.first().addToBasket()
    then:
    user.basket.readyForCheckout
    }
    }
    Test Actor
    Test system
    configuration
    Basic setup
    (using hacks)
    Test fixture
    Page object
    Verification via
    service client
    Base Spec
    Page module
    

    View Slide

11. View Slide

12. View Slide

13. View Slide

14. Tests
    use case language
    Page Objects
    page structure
    Test Actor
    workflow language
    def "fill basket"() {
    when:
    user.login()
    then:
    user.loggedIn
    }
    void logout() {
    ShopPage shopPage = to ShopPage
    shopPage.logoutLink.click()
    }
    class LoginPage extends Page {
    static url = "/mydata/login"
    LoginFormModule getLoginForm() {
    $("form#loginForm")
    .module(LoginFormModule)
    }
    String getErrorMessage() {
    $(".error-block")?.text()
    }
    }
    

    View Slide

15. class DemoSpec extends ReweShopSpec {
    ShopUserActor user = new ShopUserActor(browser, reweConfig)
    .withPickupMarketSelected()
    .withRegistered().withLoggedIn()
    def "fill basket"() {
    given:
    ShopPage shopPage = user.to(ShopPage)
    shopPage.searchFor("milch")
    when:
    shopPage.searchSuggestions.first().addToBasket()
    then:
    user.basket.readyForCheckout
    }
    }
    

    View Slide

16. Are we happy ?
    

    View Slide

17. ● Every single team can easily product high level
    fully integrated system tests
    ● Tests are executed within the CI/CD cycles of the
    teams and services
    ● Test actor keeps tests very readable &
    maintainable
    ● Minimized common test suite to monitor test
    system (service deployments are not the only
    source of defects!)
    ● Continuous activity allows continuous monitoring
    Conclusion
    ● Teams still need to keep the library up to date
    when pages or workflows change
    ● Keeping test fixtures in sync with the test system
    is a huge challenge
    ● Keeping the code base small and maintainable is
    sometimes hard
    Good Could be better
    

    View Slide

18. What next ?
    

    View Slide

19. browser 'chrome'
    environment 'int'
    user
    .withUniqueCredentials()
    .withRegistered()
    .withDeliveryMarketSelected()
    .withLoggedIn()
    .withBasketReadyForCheckout()
    

    View Slide

20. Thank You!
    @MichaKutz
    @rewedigital
    @greachconf
    

    View Slide