### Question:
CommandManager implements Reportable { public long submit(Command cmd) { Preconditions.checkNotNull(cmd, "No null commands allowed, use \"noop\""); LOG.info("Submitting command: " + cmd); long cmdId = curCommandId.getAndIncrement(); CommandStatus cmdStat = CommandStatus.createCommandStatus(cmdId, cmd); synchronized (this) { statuses.put(cmdId, cmdStat); queue.add(cmdStat); } return cmdId; } CommandManager();   CommandManager(Object[][] cmdArray); void addCommand(String cmd, Execable ex); synchronized void start(); synchronized void stop(); long submit(Command cmd); boolean isSuccess(long cmdid); boolean isFailure(long cmdid); @Override String getName(); CommandStatus getStatus(long id); @Override ReportEvent getReport();  }### Answer:
@Test(expected = NullPointerException.class) public void testSubmitNull() throws InterruptedException { CommandManager cmdman = new CommandManager(); cmdman.submit(null); }