我有一个要通过公共静态方法测试的类，该方法包含一些链接的方法调用。假设在链接方法调用期间发生异常，如何有效地处理此异常并使它返回某些特定值？
以下是测试类的代码示例。
@RunWith(PowerMockRunner.class)
@PrepareForTest({CodeWithPrivateMethod.class,CodeWithAnotherPrivateMethod.class,CodeWithYetAnotherPrivateMethod.class})
public class CodeWithPrivateMethodTest {
@Test
public void when_gambling_is_true_then_always_explode() throws Exception {
CodeWithYetAnotherPrivateMethod codeWithYetAnotherPrivateMethod = PowerMockito.spy(new CodeWithYetAnotherPrivateMethod());
PowerMockito.whenNew(CodeWithYetAnotherPrivateMethod.class).withAnyArguments().thenReturn(codeWithYetAnotherPrivateMethod);
CodeWithAnotherPrivateMethod codeWithAnotherPrivateMethod = PowerMockito.spy(new CodeWithAnotherPrivateMethod());
PowerMockito.whenNew(CodeWithAnotherPrivateMethod.class).withAnyArguments().thenReturn(codeWithAnotherPrivateMethod);
PowerMockito.doReturn(true).when(codeWithYetAnotherPrivateMethod, "getGambling");
//PowerMockito.doReturn(codeWithYetAnotherPrivateMethod).when(codeWithAnotherPrivateMethod, "getGambleValue");
PowerMockito.spy(CodeWithPrivateMethod.class);
CodeWithPrivateMethod.startGamble();
}
}
以下是被测类的代码示例
public class CodeWithPrivateMethod {
public static void startGamble() {
Boolean gamble = CodeWithAnotherPrivateMethod.getGambleValue()
.getGambling();
if (gamble) {
System.out.println("kaboom");
}else{
System.out.println("boom boom");
}
}
}
以下是从被测类调用的类的代码示例
public class CodeWithAnotherPrivateMethod {
static CodeWithYetAnotherPrivateMethod codeWithYetAnotherPrivateMethod = new CodeWithYetAnotherPrivateMethod();
public static CodeWithYetAnotherPrivateMethod getGambleValue() {
return codeWithYetAnotherPrivateMethod; //works fine
return null; // fails
}
}
以下是从被测类调用的另一个类的代码示例
public class CodeWithYetAnotherPrivateMethod {
public Boolean getGambling() {
return false;
}
}
因此，假设我从CodeWithAnotherPrivateMethod类的getGambleValue（）方法返回了空值，如何在我的测试类中有效地处理该空值？
最佳答案
这是使用Mockito指定预期异常的方法：
@Test(expected = NullPointerException.class)
public void when_gambling_is_true_then_always_explode() throws Exception {
...
在我发现这一点之前，我会做：
@Test
public void when_gambling_is_true_then_always_explode() throws Exception {
// setup omitted
try {
CodeWithPrivateMethod.startGamble();
}
catch(NullPointerException e) {
// expected
return;
}
fail("Expected NullPointerException");
}
编辑：测试多个这样静态调用彼此的类是一种严重的代码味道。单元测试应测试单个类，而内联静态调用应限于实用程序类。
另一个评论：您的示例类名称非常混乱。下次，请坚持使用Foo，Bar，Baz或Appple，梨，香蕉。
如果您没有获得NPE，那么我希望您的嘲笑/间谍活动会造成干扰。如果您在不进行模拟/间谍的情况下调用受测代码，则调用链为：
CodeWithPrivateMethod.startGamble();
->
CodeWithYetAnotherPrivateMethod value = CodeWithAnotherPrivateMethod.getGambleValue();
->
return null;
<-
value.getGambling();
<- throws NullPointerException
您到底想找出或实现什么？
编辑：这是它应如何与PowerMock一起使用
@RunWith(PowerMockRunner.class)
@PrepareForTest(CodeWithAnotherPrivateMethod.class)
public class CodeWithPrivateMethodTest {
@Mock
private CodeWithYetAnotherPrivateMethod yetAnotherInstance;
@Test
public final void testStartGamble() {
// SETUP
mockStatic(CodeWithAnotherPrivateMethod.class);
expect(CodeWithAnotherPrivateMethod.getGambleValue())
.andReturn(yetAnotherInstance);
Boolean gamblingValue = true;
expect(yetAnotherInstance.getGambling()).andReturn(gamblingValue);
replayAll();
// CALL
CodeWithPrivateMethod.startGamble();
// VERIFY
verifyAll();
}