toClose.add(it)
      }
    assertThat(cache.isClosed()).isFalse()
    cache.close()
    assertThat(cache.isClosed()).isTrue()
  }

  @Test
  fun journalWriteFailsDuringEdit() {
    set("a", "a", "a")
    set("b", "b", "b")

    // We can't begin the edit if writing 'DIRTY' fails.
    filesystem.setFaultyWrite(journalFile, true)
    assertThat(cache.edit("c")).isNull()