How do I do this in Kotlin DSL?

compileGroovy {
    dependsOn tasks.getByPath('compileKotlin')
    classpath += files(compileKotlin.destinationDir)
}

This is probably along the lines of:

tasks.named<AbstractCompile>("compileTestGroovy") {
    dependsOn(tasks.getByPath("compileTestKotlin"))
    classpath += "build/classes/kotlin/test"
}

but so far, no joy. This is follow on question to groovy is unable to resolve kotlin classes