``` configure<JUnitPlatformExtension> { ...

# spek

[sdeleuze]

configure<JUnitPlatformExtension> {
    engines {
        include("spek")
    }
}

// extension for configuration
fun JUnitPlatformExtension.engines(setup: EnginesExtension.() -> Unit) {
    when (this) {
        is ExtensionAware -> extensions.getByType(EnginesExtension::class.java).setup()
        else -> throw Exception("${this::class} must be an instance of ExtensionAware")
    }
}