data class ToDoListOwner(override val name: String):
        DdtActor<ZettaiActions>() { ➊

    val user = User(name) ➋
  
    fun `can see #listname with #itemnames`(
                listName: String,
                expectedItems: List<String>) =

        step(listName, expectedItems) { ➌

            val list = getToDoList(user, ListName(listName)) ➍
 
            expectThat(list) ➎
                    .isNotNull()
                    .itemNames
                    .containsExactlyInAnyOrder(expectedItems)
            }
    private val Assertion.Builder<ToDoList>.itemNames
            get() = get { items.map { it.description } }
    }