@Test
  public void testGetChildValue_noChild() {
    Xpp3Dom root = newXpp3Dom("root", "value");

    assertThat(MavenProjectProperties.getChildValue(root, "foo")).isEmpty();
    assertThat(MavenProjectProperties.getChildValue(root, "foo", "bar")).isEmpty();
  }
Helper for reading back layers in a {@link BuildContext}.
jib-maven-plugin/src/test/java/com/google/cloud/tools/jib/maven/MavenProjectPropertiesTest.java