how to handle exceptions in junit

Question

I wrote some test cases to test some method. But some methods throw an exception. Am I doing it correctly?

private void testNumber(String word, int number) {         


        

Answer 1

You don't need to catch the exception to fail the test. Just let it go (by declaring throws) and it will fail anyway.

Another case is when you actually expect the exception, then you put fail at the end of try block.

For example:

@Test
public void testInvalidNumber() {
  try {
      String dummy = service.convert(-1));
      Assert.fail("Fail! Method was expected to throw an exception because negative numbers are not supported.")
  } catch (OutOfRangeException e) {
      // expected
  }
}

You can use this kind of test to verify if your code is properly validating input and handles invalid input with a proper exception.