无法测试返回customException的类

在试验JUnit时，我试图测试一个简单的私有方法，如下所示，此方法接收一个String并确保其中不包含单词“Dummy”。

我知道，可以将测试放在与类相同的包中，并将方法的访问修饰符更改为包，但我想使用reflection来学习。

private void validateString(String myString) throws CustomException { if (myString.toLowerCase().matches(".*dummy.*")) throw new CustomException("String has the invalid word!"); } 

我试图通过reflection访问私有方法，但测试失败！ 它显示以下exception：

 java.lang.AssertionError:Expected test to throw (an instance of com.myproject.exception.CustomException and exception with message a string containing "String has the invalid word!") 

基于这个问题的答案，我也在捕捉InvocationTargetException 。

JUnit的

  @Rule public ExpectedException thrown = ExpectedException.none(); @Test public void shouldThrowExceptionForInvalidString() { thrown.expect(CustomException.class); thrown.expectMessage("String has the invalid word!"); try { MyClass myCls = new MyClass(); Method valStr = myCls.getClass().getDeclaredMethod( "validateString", String.class); valStr.setAccessible(true); valStr.invoke(myCls, "This is theDummyWord find it if you can."); } catch (InvocationTargetException | NoSuchMethodException | SecurityException | IllegalAccessException | IllegalArgumentException n) { if (n.getCause().getClass() == CustomException.class) { throw new CustomException("String has the invalid word!"); } } } 

Answer 1

我在上面的评论中同意@Stultuske并将测试重写为：

 @Test public void shouldThrowExceptionForInvalidString() { try { MyClass myCls = new MyClass(); Method valStr = myCls.getClass().getDeclaredMethod( "validateString", String.class); valStr.setAccessible(true); valStr.invoke(myCls, "This is theDummyWord find it if you can."); } catch (Exception e) { assert(e instanceOf CustomException); assert(e.getMessage.equals("String has the invalid word!")); } } 

或者，如果您想使用ExpectedException

 @Rule public ExpectedException thrown = ExpectedException.none(); @Test public void shouldThrowExceptionForInvalidString() { thrown.expect(CustomException.class); thrown.expectMessage("String has the invalid word!"); MyClass myCls = new MyClass(); Method valStr = myCls.getClass().getDeclaredMethod("validateString", String.class); valStr.setAccessible(true); valStr.invoke(myCls, "This is theDummyWord find it if you can."); }