private BuildContext setUpBuildContext(ContainerizingMode containerizingMode)
      throws InvalidImageReferenceException, IOException, CacheDirectoryCreationException {
    JavaContainerBuilder javaContainerBuilder =
        JavaContainerBuilder.from(RegistryImage.named("base"))
            .setAppRoot(AbsoluteUnixPath.get("/my/app"))
            .setModificationTimeProvider((ignored1, ignored2) -> EPOCH_PLUS_32);
    JibContainerBuilder jibContainerBuilder =
        mavenProjectProperties.createJibContainerBuilder(javaContainerBuilder, containerizingMode);
    return JibContainerBuilderTestHelper.toBuildContext(
        jibContainerBuilder, Containerizer.to(RegistryImage.named("to")));
  }
Helper for reading back layers in a {@link BuildContext}.
jib-maven-plugin/src/test/java/com/google/cloud/tools/jib/maven/MavenProjectPropertiesTest.java