How to enjoy E2E testing in Kotlin / Spring
summary
Claims TDD E2E for REST APIs in Kotlin Spring is practical and pleasant, then demonstrates it: tests are functions in Kotest, HTTP calls use WebTestClient, third‑party APIs are stubbed with WireMock while the database runs as a real Postgres in Testcontainers, and MockK replaces beans in Spring. A small client/offices API is driven red‑green‑refactor style, tests run in IntelliJ, server starts and Postman shows the expected JSON, and reusable Testcontainers keeps iteration fast.
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chapters (24)
- 0:00Introduction
- 1:05Web app architecture overview
- 2:31Testing strategies in Spring
- 3:54TDD for API development
- 4:58Choosing testing tools
- 6:01Why Kotest for Kotlin
- 7:08Mocking with MockK
- 8:17Testing with real DBs
- 9:21Speeding up tests with Testcontainers
- 9:41Running real servers for E2E
- 10:27Encapsulating API calls
- 11:10Preparing test data
- 12:14Kotlin DSL for test data
- 12:58Optimizing test speed
- 14:24Live coding intro
- 15:27TDD client controller
- 18:22Mocking in demo
- 20:23Adding office creation
- 22:07Testing office inclusion
- 23:39Handling office deactivation
- 26:59Refactoring acceptance criteria
- 27:20Validating app with tests
- 28:06Key takeaways
- 28:26Q&A
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