java - 使用 JUnit 4 测试自定义异常的错误代码

Question

我想测试异常的返回码。这是我的生产代码:

class A {
  try {
    something...
  }
  catch (Exception e)
  {
    throw new MyExceptionClass(INTERNAL_ERROR_CODE, e);
  }
}

以及相应的异常:

class MyExceptionClass extends ... {
  private errorCode;

  public MyExceptionClass(int errorCode){
    this.errorCode = errorCode;
  }

  public getErrorCode(){ 
    return this.errorCode;
  }
}

我的单元测试:

public class AUnitTests{
  @Rule
  public ExpectedException thrown= ExpectedException.none();

  @Test (expected = MyExceptionClass.class, 
  public void whenRunningSomething_shouldThrowMyExceptionWithInternalErrorCode() throws Exception {
      thrown.expect(MyExceptionClass.class);
      ??? expected return code INTERNAL_ERROR_CODE ???

      something();
  }
}

Answer 1

简单:

 @Test 
 public void whenSerialNumberIsEmpty_shouldThrowSerialNumberInvalid() throws Exception {
  try{
     whenRunningSomething_shouldThrowMyExceptionWithInternalErrorCode();     
     fail("should have thrown");
  }
  catch (MyExceptionClass e){
     assertThat(e.getCode(), is(MyExceptionClass.INTERNAL_ERROR_CODE));
  }

这就是你所需要的:

• 您不想期待那个特定的异常，因为您想要检查它的某些属性
• 您知道您想要进入那个特定的捕获 block ；因此，当调用没有抛出时你就失败了
• 您不需要任何其他检查 - 当该方法抛出任何其他异常时，JUnit 无论如何都会将其报告为错误