Kotlin Spring Boot, REST API for demo banking project

Simple REST API using Kotlin Spring Boot in TDD (Test Driven Development). I used JUnit5 for testing the project. Spring Boot has many amazing features.

✅ Fast - fast feedback loop, run often

✅ Isolated - independent, arbitary order

✅ Repeatable - same result each time, not flaky

✅ Self-validating - actual vs expected

✅ Timely - with (or even before!) production code

With test driven development, you wrote first test and it must fail first, then you write the actual code and make it pass