public Optional<AbsoluteUnixPath> getAppRoot() {
    if (appRoot == null) {
      return Optional.empty();
    }
    return Optional.of(AbsoluteUnixPath.fromPath(appRoot));
  }
@Test
  public void testParse_appRoot() {
    War warCommand =
        CommandLine.populateCommand(
            new War(), "--target=test-image-ref", "--app-root=/path/to/app", "my-app.war");
    assertThat(warCommand.getAppRoot()).hasValue(AbsoluteUnixPath.get("/path/to/app"));
  }