// Once the journal has a failure, subsequent writes aren't permitted.
    filesystem.setFaultyWrite(journalFile, false)
    assertThat(cache.edit("d")).isNull()

    // Confirm that the fault didn't corrupt entries stored before the fault was introduced.
    cache.close()
    cache =
      DiskLruCache(filesystem, cacheDir, appVersion, 2, Int.MAX_VALUE.toLong(), taskRunner).also {
        toClose.add(it)
      }

 *
 * <h3>Non-preconditions</h3>
 *
 * <p>It is of course possible to use the methods of this class to check for invalid conditions
 * which are <i>not the caller's fault</i>. Doing so is <b>not recommended</b> because it is
 * misleading to future readers of the code and of stack traces. See <a
 * href="https://github.com/google/guava/wiki/ConditionalFailuresExplained">Conditional failures