在JUnit中测试捕获的异常

Question

I am trying to create a test that verifies that my code (see below for the pseudocode) correctly catches an exception. I know that JUnit is able to test whether the code throws an exception with the following code:

@Test (expected = ArrayIndexOutOfBoundsException.class)

However, my original code of the software I'm testing catches this exception and prints a message

catch (ArrayIndexOutOfBoundsException E) {
    System.out.print("The output should be of even length!");
}

Is there any way for JUnit to verify this message? Or should I change something in my catch phrase?

Note: I have read that I should use the following:

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

@Test
public void decodeOddLengthInput() {
    thrown.expect(ArrayIndexOutOfBoundsException.class);
    thrown.expectMessage("Message");

But the program crashes because it doesn't recognize the ExpectedException object.

Pseudocode of the method I am trying to test (don't post the exact thing because of privacy reasons):

public String decode(byte[] array){
try{
for(int i= 0; i<array.length; i= i+2){
//basically it crashes when input is an array of odd length (because of i=i+2)
   get byte at array[i] and turn it into a string;
   }
 }
catch (ArrayIndexOutOfBoundsException E) { System.out.print("Message!");}

  return string ;
  }

Answer 1

Your software method isn't re-throwing the exception with a message. It is simply eating the exception by printing the message. In this case, calling test method will never know about this exception, so you can not test this scenario or verify the message.