data: String,
  ) {
    assertThat(nextEvent()).isEqualTo(Event(id, type, data))
  }

  fun assertOpen(): EventSource {
    val event = nextEvent() as Open
    return event.eventSource
  }

  fun assertClose() {
    nextEvent() as Closed
  }

  fun assertFailure(message: String?) {
    val event = nextEvent() as Failure
    if (message != null) {
      assertThat(event.t!!.message).isEqualTo(message)