@Test
public void testNextRevision() {

    final RevisionManager revisionManager = new RevisionManager(ds);
    assertEquals(Long.MIN_VALUE + 1, revisionManager.nextRevision());
    assertEquals(Long.MIN_VALUE + 2, revisionManager.nextRevision());
    assertEquals(Long.MIN_VALUE + 3, revisionManager.nextRevision());
    verify(updateOperations, times(3)).inc(anyString());
}