@Test
public void dontFailWithoutParentForGetThreadGroup() {
managerWithoutOriginal.getThreadGroup();
}
@Test
public void provideThreadGroupOfOriginalSecurityManager() {
ThreadGroup threadGroup = new ThreadGroup("dummy name");
when(originalSecurityManager.getThreadGroup()).thenReturn(threadGroup);
assertThat(managerWithOriginal.getThreadGroup(), is(threadGroup));
}