private lateinit var file: File

  @BeforeEach
  fun setUp() {
    file = File(tempDir, "test")
  }

  @AfterEach
  fun tearDown() {
    executor.shutdown()
  }

  @Test
  fun singleSource() {
    val upstream = Buffer()
    upstream.writeUtf8("abcdefghijklm")
    val relay = edit(file, upstream, metadata, 1024)
    val source = relay.newSource()
    val sourceBuffer = Buffer()