@Test
  public void testNullPaths() {
    ClassLoader rootLoader = Thread.currentThread().getContextClassLoader();
    AddToClassPathAction action = new AddToClassPathAction(rootLoader, null);
    UDFClassLoader childLoader = action.run();
    assertURLsMatch(
        "When newPaths is null, loader shall be created normally with no extra paths.",
        Collections.emptyList(), childLoader.getURLs());
  }
Minimal tests for AddToClassPathAction class. Most of the tests don't use
{@link java.security.AccessController#doPrivileged(java.security.PrivilegedAction)},
presumably the tests will not be executed under security manager.
ql/src/test/org/apache/hadoop/hive/ql/exec/TestAddToClassPathAction.java