Path getLayerFile(DescriptorDigest layerDigest, DescriptorDigest layerDiffId) {
    return getLayerDirectory(layerDigest).resolve(getLayerFilename(layerDiffId));
  }
@Test
  public void testGetLayerFile() throws DigestException {
    DescriptorDigest layerDigest =
        DescriptorDigest.fromHash(
            "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa");
    DescriptorDigest diffId =
        DescriptorDigest.fromHash(
            "bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb");

    Assert.assertEquals(
        Paths.get(
            "cache",
            "directory",
            "layers",
            "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
            "bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"),
        TEST_CACHE_STORAGE_FILES.getLayerFile(layerDigest, diffId));
  }