测试“处理例外” JUnit的 [英] test "handled exceptions" junit

问题描述

  public boolean exampleMethod（）{
 
尝试{
整数temp = null; 
 temp.equals（null）; 
 return 
} catch（Exception e）{
 e.printStackTrace（）; 
} 
} 
  

我想测试它

  public void test_exampleMethod（）{} 
  

我试过

  @Rule 
 public ExpectedException expectedException = ExpectedException.none（）; 
 
 public void test_exampleMethod（）{
 expectedException.expect（JsonParseException.class）; 
 exampleMethod（）; 
} 
  

但是因为异常被处理，所以没有工作。

我也尝试过

  @Test（expected = JsonParseException.class）
  

但同样的问题...异常处理

我知道我可以做

  assertTrue（if（exampleMethod（）））
  

但它仍然会将堆栈跟踪打印到日志中。我更喜欢干净的日志...任何建议？

解决方案

你不能测试一个方法在内部做什么。这是完全隐藏的（除非有副作用，外面可见）。

测试可以检查特定的输入方法返回预期的输出。但你不能检查，这是如何做的。所以你没有办法检测是否有一个你已经处理的异常。

所以：不要处理异常（让测试捕获异常）或者返回一个告诉你异常的特殊值。

无论如何，我希望你的真正的异常处理比你的例子更明智。

I have a method with a handled exception:

public boolean exampleMethod(){

    try{
      Integer temp=null;
      temp.equals(null);
      return
      }catch(Exception e){
        e.printStackTrace();
      }
    }

I want to test it

public void test_exampleMethod(){}

I have tried

@Rule
public ExpectedException expectedException=ExpectedException.none();

public void test_exampleMethod(){
    expectedException.expect(JsonParseException.class);
    exampleMethod();
}

but that doesnt work because the exception is handled inside.

I also tried

@Test(expected=JsonParseException.class)

but same issue...the exception is handled

I know that I can just do

assertTrue(if(exampleMethod()))

but it will still print the stack trace to the log. I would prefer clean logs...Any suggestions?

解决方案

You cannot test what a method is doing internally. This is completely hidden (unless there are side effects, that are visible outside).

The test can check that for a specific input the method returns a expected output. But you can not check, how this is done. So you have no way to detect if there was a exception that you have handled.

So: either don't handle the exception (let the test catch the exception), or return a special value that tells you about the exception.

Anyway, I hope your real exception handling is more sensible than in your example.

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