Ktor as Mock HTTP Server For Integration Testing (JUnit5, Kotlin)
This tutorial demonstrates an easy replacement of the mock-server. If you write in Kotlin and need to validate endpoint calls correctness, look no further! You can check the mock-server tutorial if you need a monster
Let’s model service A which talks to service B over HTTP. First is ours, and service B belongs to a well-funded government company which has no staging or dev environments, production only. Oh, sad.
You can use mocks to verify connection works fine. This is ok in 81% of cases, but sometimes you can’t inject mocks (legacy code creates it on the fly?).
Our application will call some endpoint and we will write a test for it
For the test to work we create a Ktor server and listen for the endpoint calls.
To begin, we implement server start up on a random port, with Jackson serialization and listening for a /report endpoint.
Every call on /report endpoint populates reports collection which we will use in the test to verify it worked
That is it! We have a pretty flexible endpoint capturing facility and can enjoy green tests. Here, enjoy:
You can find a complete working example here
