Fake it until you make it. WireMock, Testcontainers, Quarkus and Gradle

estcontainers has become one of the most popular tools for software integration testing. If you can put your system-under-test into a container, Docker compose cluster or a pod, this is what you're likely to use. If your target isn't ready, not containerizable or just too heavy for testing as is, you can always use mock testing frameworks, e.g. WireMock or MockServer in the JVM ecosystem. Can you combine both approaches? Sure!

In this talk, we will classify integration testing and discuss application areas for WireMock and Testcontainers, and discuss which tool to choose for each use-case. And why not both? We will discuss putting WireMock into Testcontainers, and getting the best from their features thanks to the new WireMock modules for Testcontainers. Last but not least, we will see how to put WireMock in front of the Testcontainers or your real system to do deeper tests or even chaos engineering.

P.S: We will focus on the Java, Golang or Rust examples, but the same approaches can be used everywhere

Transcript

1. Oleg Nenashev, Gradle Inc. @oleg_nenashev Fake it until you `make it` API Integration testing with Testcontainers and WireMock IET Summit, 27 January 2025
2. Async Q&A: Gradle Community Slack, Testcontainers and WireMock Slack speakerdeck.com/onenashev
3. About You 3
4. https://jobs.mobiliar.ch/Vacancies/4624/Description/1
5. You Have a LOT to Integrate TODO: Tech logos 5
6. When IT Goes wrong 6
9. Do you `make it`? IT - Integration Tests 9
11. Integration Testing 11 • Multiple technology stacks and toolchains • Many teams involved • Sacred knowledge • [Almost] always too late
14. About Me 14 and Gradle
15. > whoami @oleg_nenashev oleg-nenashev Dr. Nenashev / Mr. Jenkins Community Builder, Gradle Developer Tools Hacker Independent Consultant #RussiansAgainstPutin #StandWithUkraine
16. rts.ch/info/regions/neuchatel/12836885-la-population-neuchateloise-en-hausse-malgre-un-recul-dans-les-montagnes.html
17. * Saw (2004) Yes, that elephant in the room
18. 18 Developer Productivity Engineering (DPE)
20. About You 20 Maven or Gradle ?
21. Disclaimer Gradle == Gradle Build Tool in this talk It’s not a “Gradle vs Maven” talk. It is not a Gradle one I use both Maven and Gradle IMO: There is no place for “vs” in open source
22. 2 2 And we mean it Valentine Day’s post
23. 23 https://gradle.com/develocity/
24. ◦ Build Scans and Troubleshooting ◦ Local and Distributed build caching ◦ Predictive Test Selection ◦ Flaky Tests Detection ◦ Local build observability ◦ // And more! https://gradle.com/develocity/
25. For many FOSS projects: we sponsor Develocity licenses/hosting API for integration and developer pipelines Maven, Bazel and sbt users welcome! gradle/develocity-oss-projects gradle/develocity-oss-projects
26. +
27. See ge.apache.org helps Used in Beam, Groovy, Kafka, Lucent, Pulsar, Solr, etc. • 37 onboarded projects • 31 days per week - savings from the build cache • 116 days per week - savings from all caching • 30k builds per week • 503d of total build time per week
28. DPE is Like SRE, but for Developer Productivity 28
29. 29 Developer Productivity Engineering (DPE) • Culture • Metrics & Observability • Developer Tools • Developer Services
32. 32 Staging & QA Tests Build Integration tests Build Tests Gaining confidence in you software “Shift Left” with modern tools
33. 33 https://martinfowler.com/articles/ mocksArentStubs.html
34. Ways to do API integration testing 1. Testing against Production/Staging servers 2. Testing against a simplified/containerized instance (e.g. Testcontainers) 3. Modeling (aka Mocking) at the API provider level (e.g. WireMock) 4. Mocking at the code level Slow Fast Nope Accu- rate * For Testcontainers, see the slides
35. Ways to do API integration testing 1. Testing against Production/Staging servers 2. Testing against a simplified/containerized instance (e.g. Testcontainers) 3. Modeling (aka Mocking) at the API provider level (e.g. WireMock or Microcks) 4. Mocking at the code level Slow Fast Nope Accu- rate * For Testcontainers, see the slides
37. Example - Java 37
38. https://testcontainers.com/modules/
39. 39 LOCAL STACK https://testcontainers.com/modules/
40. 40 SDKs testcontainers.org … and
41. 41 github.com/testcontainers/ testcontainers-go
42. Demo Time 42 github.com/oleg-nenashev/mocks-as-code-demo/ tree/main/1_application
43. No Implementation? 43 Fake it until you “$ make it”
44. Ways to do API integration testing 1. Testing against Production/Staging servers 2. Testing against a simplified/containerized instance (e.g. Testcontainers) 3. Modeling (aka Mocking) at the API provider level (e.g. WireMock or Microcks) 4. Mocking at the code level Slow Fast Nope Accu- rate * For Testcontainers, see the slides
45. API Mocking for Java. Examples en.wikipedia.org/wiki/Comparison_of_API_simulation_tools Proprietary Open Source `
46. API Mocking Tools Main implementation in Java Native lib, Docker images and Testcontainers modules Support for GraalVM Rich Ecosystem Sandbox CNCF Project Golang / Microservice arch Docker image, Testcontainers module, All-in K8s Charts Less Rich Ecosystem
48. wiremock.org/docs/stubbing IF (request_url) THEN (response) * * it gets MUCH more complex WireMock Config JSON: Client library response request Client App Mock API Server HTTP/2 API Mocking 101
49. WireMock Ecosystem & Features wiremock.org/docs
50. WireMock Ecosystem wiremock.org/docs
51. WireMock in Java wiremock.org/docs/stubbing
52. WireMock Ecosystem / Java • Java • Kotlin • Scala • Groovy • Clojure • (?)Android 52 • JUnit 4/5 • Testcontainers • Sprint Boot • Spring Cloud Contract • Quarkus • Maven/Gradle • Spock • Pact
53. Example - JUnit 5 53
54. WireMock Plugin for Gradle 54 William-Hill-Online/wiremock-gradle-plugin
55. 55 WireMock has an official Testcontainers module! testcontainers.com/modules/wiremock
56. WireMock as a Proxy Tests API Provider • Fault injection • Recording • Protocol Verification
57. 57 DEMO TIME https://github.com/wiremock/wiremock-docker
58. WireMock or Testcontainers?
59. Choosing a right tool * • Need database or complex dynamic environment? ◦ YES => Testcontainers • Do you have a ready implementation? ◦ NO => WireMock/Microcks • Is it containerized and lightweight? ◦ NO => WireMock/Microcks • Can you easily trigger the desired scenarios? ◦ NO => WireMock/Microcks • Else: => Testcontainers 59 * Your mileage may vary ** More later *** I just like footnotes * Likely, you want to use both
61. 61 WireMock has an official Testcontainers module! testcontainers.com/modules/wiremock
62. Proxy can be made transparent in your test! 62 Tests
63. WireMock Proxy? Why? • Record & Playback for Request sequences • Reverse engineering of legacy undocumented APIs • NEW: OpenAPI Standard Compliance Verification (in 3.0 Beta) • Emulating complex cases ◦ Overriding particular responses ◦ Emulating response sequences / Stateful behavior ◦ Failure Injection 63
64. Quarkus or Spring What do you use ?
65. If you like / use You can do [almost] the same as below Devoxx BE Video with Oleg Shelajev: youtube.com/watch?v=eFILbyaMI2A Our demo: github.com/testcontainers-community/ testcontainers-wiremock-demo 65 TL;DR: Two Olegs
66. Source: https://www.codelikethewind.org/2022/05/03/3-reasons- why-all-java-developers-should-consider-quarkus/ • Reference implementation of new Java Developer Experience • Spring Boot is catching up • Micronaut & Co are great, too
67. Quarkus Dev Services • Automatic provisioning of unconfigured services in development and test mode • Transparent to your application • Mostly containerized, with Testcontainers 67 https://quarkus.io/guides/dev-services
68. Dev Services • Mostly containerized, with Testcontainers 68 Presentation by Daniel Oh: https://www.youtube.com/watch?v=moIFTj9KW1c
70. 70 docs.quarkiverse.io/quarkus-wiremock/dev/index.html
71. @QuarkusTest or @QuarkusIntegrationTest
72. And a Quarkus Dev Service! docs.quarkiverse.io/quarkus-wiremock/dev/index.html
73. docs.quarkiverse.io/qu arkus-wiremock/dev/in dex.html#extension-co nfiguration-reference
74. 74 DEMO TIME https://github.com/oleg-nenashev/gradle-quarkus-plugin-demo
77. Gradle Build Scan & Develocity 77
78. More Demos • Simple WireMock and Testcontainers demo: github.com/testcontainers-community/testcontainers-wiremock-demo • WireMock and Docker integration tests: https://github.com/wiremock/wiremock-docker • Quarkus Dev Service for WireMock and Testcontainers, in Gradle: https://github.com/oleg-nenashev/gradle-quarkus-plugin-demo • Spring Boot + Testcontainers and WireMock + LocalStack: https://github.com/oleg-nenashev/mocks-as-code-demo
79. Lessons Learned 79
80. Takeaways 80 • Shift left the integration testing • API Mocking / abstraction are great… when used right • There is no silver bullet • WireMock and Testcontainers address their own use-cases • They work well together!
81. Choosing a right tool * • Need database or complex dynamic environment? ◦ YES => Testcontainers • Do you have a ready implementation? ◦ NO => WireMock/Microcks • Is it containerized and lightweight? ◦ NO => WireMock/Microcks • Can you easily trigger the desired scenarios? ◦ NO => WireMock/Microcks • Else: => Testcontainers 81 * Your mileage may vary ** More later *** I just like footnotes * Likely, you want to use both
82. Keep Learning Tools 82 * AKA: Burning Out 101
84. It’s [always] a great time to contribute! gradle.github.io/community/contributing testcontainers.org/contributing wiremock.org/participate 84
85. GitHub: oleg-nenashev Twitter: @oleg_nenashev Gradle Community Slack, #developer-productivity-engineering Questions? Testcontainers Slack 85
86. References • This presentation: speakerdeck.com/onenashev/ • Gradle: https://gradle.com • Gradle Build Tool: https://gradle.org • Gradle Build Scan: scans.gradle.com
87. Credits 87 • All WireMock, Testcontainers and Quarkus contributors • Siva Prasad Reddy, JetBrains and Oleg Shelajev, Docker • All FOSS folks