@Test
public void testRelativization() throws Exception {

    //test assertion error if alleged child is not actually child
    Path root = Paths.get("root/abc/def").toAbsolutePath();
    Path allegedChild = Paths.get(root.getParent().getParent().toAbsolutePath().toString());
    try {
        FSFileResource r = new FSFileResource(root, allegedChild);
        fail("should have had assertion error: alleged child not actually child of root");
    } catch (AssertionError e) {
    }
    //test regular workings
    root = Paths.get("root/abc/def");
    Path child = Paths.get(root.toString(), "ghi/jkl/lmnop.doc");
    FSFileResource r = new FSFileResource(root, child);
    String id = r.getResourceId();
    assertTrue(id.startsWith("ghi"));
    assertTrue(id.endsWith("lmnop.doc"));
}