private BuildContext setUpBuildContext()
      throws InvalidImageReferenceException, IOException, CacheDirectoryCreationException {
    return setUpBuildContext(ContainerizingMode.EXPLODED);
  }
Helper for reading back layers in a {@link BuildContext}.
jib-maven-plugin/src/test/java/com/google/cloud/tools/jib/maven/MavenProjectPropertiesTest.java