Taken from https://github.com/kanawish/android-mvi-sample/tree/lesson/testing-state-machines while learning MVI

AddEditTaskIntentFactory.kt

    companion object {
        /**
         * Creates an intent for the TaskEditor state machine.
         *
         * Utility function to cut down on boilerplate.
         */
        inline fun <reified S : TaskEditorState> editorIntent(
                crossinline block: S.() -> TaskEditorState
        ): Intent<TaskEditorState> {
            return intent {
                (this as? S)?.block()
                        ?: throw IllegalStateException("editorIntent encountered an inconsistent State. [Looking for ${S::class.java} but was ${this.javaClass}]")
            }
        }
    }