Question

I’m trying to write a unit-test to verify that it’s impossible to create an instance of a certain object with a negative value.

My first test works OK as expected – it should pass.

My second test produces the IllegalArgumentException as expected, however the @Test(expected=IllegalArgumentException.class) does not absorb the error as I expected it to. In fact the test appears to behave exactly as if the @Test line were not there at all!

So what am I doing wrong?

package numbers;
import org.junit.Test;
import junit.framework.TestCase;
public class TestPositiveMoney extends TestCase {

    public void testConstructFromLong(  ) {
        // Works OK
        PositiveMoney x0 = new PositiveMoney( 3L );
    }

    @Test(expected=IllegalArgumentException.class)
    public void testConstructInvalid( ) {
        // This statement is intended to fail
        PositiveMoney x0 = new PositiveMoney( -3L ); // Illegal
    }

}

FYI, the second test produces the following TB:

java.lang.IllegalArgumentException: Negative value -3 not allowed
    at numbers.PositiveMoney.<init>(PositiveMoney.java:48)
    at numbers.TestPositiveMoney.testConstructInvalid(TestPositiveMoney.java:13)

Answer 1

• extends junit.framework.TestCase is a JUnit 3 technique.
• @Test(expected=IllegalArgumentException.class) is for JUnit 4.

It seems you’re using a test runner from JUnit 3. Try the following:

• add @Test to your first test
• drop extends TestCase clause

If it doesn’t help—especially if the tests are not run any more—check what JUnit version you’re using.
If you use maven, try -X command-line switch.