使用Mockito模拟链接方法调用

Question

我需要模拟这个：

 void handleCellPreview(CellPreviewEvent<List<String>> event) {
    Element cellElement = event.getNativeEvent().getEventTarget().cast();
 }

我正在这样做：

CellPreviewEvent<List<String>> cellPreviewEvent = Mockito.mock(
        CellPreviewEvent.class, Mockito.RETURNS_DEEP_STUBS);
Element cellElement = Mockito.mock(Element.class, Mockito.RETURNS_DEEP_STUBS);
EventTarget eventTarget = Mockito.mock(EventTarget.class);
  Mockito.when(cellPreviewEvent.getNativeEvent().getEventTarget().cast()).thenReturn(cellElement);

我会得到以下错误：

testHandleCellPreview(client.view.MyViewTest)java.lang.NullPointerException
    at com.google.gwt.dom.client.NativeEvent.getEventTarget(NativeEvent.java:137)
    atclient.view.MyViewTest.testHandleCellPreview(MyViewTest.java:76)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

我也看到了下面的同样问题：
模拟或存根用于链式电话

有人可以指出我缺少的东西吗？

谢谢，
Mohit

Answer 1

我认为问题是您正在尝试在客户端浏览器环境之外执行GWT代码。GWT设计为转换为JavaScript并在浏览器上运行。我不确定它是否可以使用。

我注意到NativeEvent的第137行似乎是DomImpl.impl.eventGetTarget。这使我相信DomImpl.impl是null。

我通过查看代码找到了以下内容：

45  public static <T> T create(Class<?> classLiteral) {
46     if (sGWTBridge == null) {
47       /*
48        * In Production Mode, the compiler directly replaces calls to this method
49        * with a new Object() type expression of the correct rebound type.
50        */
51       throw new UnsupportedOperationException(
52           "ERROR: GWT.create() is only usable in client code!  It cannot be called, "
53               + "for example, from server code.  If you are running a unit test, "
54               + "check that your test case extends GWTTestCase and that GWT.create() "
55               + "is not called from within an initializer or constructor.");
56     } else {
57       return sGWTBridge.<T> create(classLiteral);
58     }
59   }

您是否扩展了GWTTestCase

Answer 2

您需要在父实体中再次设置模拟对象。因此，在运行 - 时间，它使用模拟的对象。

cellPreviewEvent.setCellElement(cellElement);
cellPreviewEvent.setEventTarget(eventTarget);

完整的代码看起来像：

CellPreviewEvent<List<String>> cellPreviewEvent = Mockito.mock(
        CellPreviewEvent.class, Mockito.RETURNS_DEEP_STUBS);
Element cellElement = Mockito.mock(Element.class, Mockito.RETURNS_DEEP_STUBS);
EventTarget eventTarget = Mockito.mock(EventTarget.class);
cellPreviewEvent.setCellElement(cellElement);
cellPreviewEvent.setEventTarget(eventTarget);
  Mockito.when(cellPreviewEvent.getNativeEvent().getEventTarget().cast()).thenReturn(cellElement);