http4k VS Kotest

You named Express as an example for a good framework - I'd say both http4k and ktor come close to it. Spring Boot would really be on the other end and I met lots of JS/TS devs that didn't even want to touch it. I did have the same impression than you though: Documentation for ktor is not great at all.

http4k has excellent documentation and very simple concepts.

I couple of years ago I was lucky to use http4k, a server as a function web library for Kotlin. It was such a wonderful change compared to every other technologies available in both Java and Kotlin. It's simple.

Testing becomes so much easier too, as one can instantiate a the whole web routing aspect, without having to bind it to a port and having to send real http requests.

If strongly suggest people to take a look at it. It's not perfect, but it's a lot simpler than other frameworks and libraries. And it's a shift in some of the current mentality of using heavy frameworks (such as spring boot) which blow up anyone's cognitive load.

https://github.com/http4k/http4k

http4k with the contract, format-jackson, and server-undertow modules

As you might know, Advent of Code will begin this Friday! If, like me, you want to have a go at solving the puzzles in Kotlin, I would like to share with you a little library I've developed to reduce boilerplate and solve the puzzles in a test-driven approach. It is based on Kotest, a modern and Kotlin-first test framework.

Kotlin testing with Kotest and MockK

As a matter of fact, in the previous examples, we have shifted a bit away from the TDD standards in the meaning that we test not only the operability of our code, but rather check if the code runs according to certain specifications (Given/When/Then). These specifications are our tests, and the syntactic sugar in the form of the possibility to give clear names to the tests using DisplayName and the grouping of the tests by a set of similar attributes helps us clearly formulate these specifications. There is an entire family of frameworks in different languages that allow us to create such specifications: for Java it is Spock, for Ruby—RSpec, and for Kotlin—Spek and Kotest frameworks. Below, I will go into more detail about them.

I've tried so many times. SO MANY. I love the idea of mutation testing. Even chatGPT couldn't help me. It just made up fake mutation testing frameworks to try. To me, pitest is dead. kotest is not mutation testing, but it's property testing is the next best thing I have found to revolutionize your unit tests.

The extensions are not particularly useful in this scenario because the described functionality can be incorporated into the Host class. On the other hand, they flourish in test frameworks like Kotest and enable the rapid development of useful add-ons like custom matchers. Extending third-party libraries with utility functions is another prevalent use case. In the next sections, we'll zero in on this specific aspect.

We're using Kotest for our unit tests and are quite happy with it.

Basic testing in Kotlin with Kotest built for kotlin specificatlly (upcoming)

Here you are: https://github.com/kotest/kotest/issues/189