正确的做法是重组代码，使其更具可测试性，如下所示。重组代码以消除对Date的直接依赖关系将使您可以为正常运行时和测试运行时注入不同的实现：
interface DateTime { Date getDate();}class DateTimeImpl implements DateTime { @Override public Date getDate() { return new Date(); }}class MyClass { private final DateTime dateTime; // inject your Mock DateTime when testing other wise inject DateTimeImpl public MyClass(final DateTime dateTime) { this.dateTime = dateTime; } public long getDoubleTime(){ return dateTime.getDate().getTime()*2; }}public class MyClassTest { private MyClass myClassTest; @Before public void setUp() { final Date date = Mockito.mock(Date.class); Mockito.when(date.getTime()).thenReturn(30L); final DateTime dt = Mockito.mock(DateTime.class); Mockito.when(dt.getDate()).thenReturn(date); myClassTest = new MyClass(dt); } @Test public void someTest() { final long doubleTime = myClassTest.getDoubleTime(); assertEquals(60, doubleTime); }}
