package junit.extensions;

import junit.framework.* ;

/**
 * A TestCase that expects an Exception of class fExpected to be thrown.
 * The other way to check that an expected exception is thrown is:
 * <pre>
 * try {
 *   shouldThrow();
 * }
 * catch (SpecialException e) {
 *   return;
 * }
 * fail("Expected SpecialException");
 * </pre>
 *
 * To use ExceptionTestCase, create a TestCase like:
 * <pre>
 * new ExceptionTestCase("testShouldThrow", SpecialException.class);
 * </pre>
 */
public class ExceptionTestCase extends TestCase {
        Class fExpected;

        public ExceptionTestCase(String name, Class exception) {
                super(name);
                fExpected = exception;
        }

        /**
         * Execute the test method expecting that an Exception of
         * class fExpected or one of its subclasses will be thrown
         */
        protected void runTest() throws Throwable {
                try {
                        super.runTest();
                }
                catch (Exception e) {
                        if (fExpected.isAssignableFrom(e.getClass()))
                                return;
                        else
                                throw e;
                }
                fail("Expected exception " + fExpected);
        }
}