How to do unit test for Exceptions?

Question

As you know, exception is thrown at the condition of abnormal scenarios. So how to analog these exceptions? I feel it is challenge. For such code snippets:

p         


        

Answer 1

Many unit testing frameworks allow your tests to expect exceptions as part of the test. JUnit, for example, allows for this.

@Test (expected=IndexOutOfBoundsException.class) public void elementAt() {
    int[] intArray = new int[10];

    int i = intArray[20]; // Should throw IndexOutOfBoundsException
}