@Override
  public String getFileChecksum(Path sourceFile)
      throws IOException {
    FileSystem fs = sourceFile.getFileSystem(this.conf);
    try (FSDataInputStream in = fs.open(sourceFile)) {
      return this.checksum.computeChecksum(in);
    }
  }
@Test(expected = FileNotFoundException.class)
  public void testNonexistantFileChecksum() throws Exception {
    Path file = new Path(TEST_ROOT_DIR, "non-existant-file");
    client.getFileChecksum(file);
  }