I ran into an issue with TestKit and Kotlin. I define an extension, e.g.:

interface MyLibraryExtension {
  fun getValue(): String
  ...
}

I create such an object and register it as

myLibrary

extension upon applying the plugin. I want to test it with TestKit. In a test project

build.gradle.kts

: • This works:

println(myLibrary::class.java.getMethod("getValue").invoke(myLibrary))

• But this fails:

println(myLibrary.getValue())

with "Unresolved reference: getValue". So Gradle under TestKit: • Finds the extension object just fine. • It can inspect it and use it via reflection just fine. • It cannot deal with the extension without reflection...?! Am I missing something for this to work in TestKit? It all works fine if I try it out on the CLI without TestKit. Update: It even works if I use Groovy

build.gradle

instead of Kotlin

build.gradle.kts

in the test project...

This is probably a class loader issue and related to the way the classes are added to the test process. When the accessors for the Kotlin DSL are generated, it must probably does not see the extension class and this generates an accessor that returns

Any

which does not have that method.