Question

This might be a conceptually stupid question, but it also might not and since I am still a student I think I should I have no problem asking.

Imagine you have a method that if given certain conditions it will throw an NumberFormatException. I want to write a Unit Test to see if the exception is being correctly thorwn. How can I achieve this?

P.S. I am using JUnit to write the Unit Tests.

Thanks.

Answer 1

As other posters suggested, if you are using JUnit4, then you can use the annotation:

@Test(expected=NumberFormatException.class);

However, if you are using an older version of JUnit, or if you want to do multiple “Exception” assertions in the same test method, then the standard idiom is:

try {
   formatNumber("notAnumber");
   fail("Expected NumberFormatException");
catch(NumberFormatException e) {
  // no-op (pass)
}