JUnit: successful test if an exception is thrown

Question

Is it possible that the JUnit test will succeed if it returns the expected exception?

Can you tell me how to implement such a test with a simplified example?

Many thanks.

Answer 1

Why can't you just catch your exception in the test? There are different ways to do this. Like annotations @Test(expected = DataAccessException.class), and it also needs to be used on a case-by-case basis. But below is what I suggest.

public class TestCase{
    @Test
    public void method1_test_expectException () {
     try{
     // invoke the method under test...
     Assert.fail("Should have thrown an exception"); 
     // This above line would only be reached if it doesnt throw an exception thus failing your test. 
                }
     catch(<your expected exception> e){
       Assert.assertEquals(e.getcode(), somce error code);
     }
 }

Several advantages using this approach.

• If you have your own exception with an error code, you can argue for an error code. So tighten your test.
• , . ( , , . .)

Answer 2

JUnit4 , ExpectedException, @Rule,

import org.junit.rules.ExpectedException;
import org.junit.Rule;
import org.junit.Test;


public class MyTestClass {
  @Rule 
  public ExpectedException thrown = ExpectedException.none();

  @Test
  public void aTestThatSucceedsOnlyIfRuntimeExceptionIsThrown() {
      thrown.expect(RuntimeException.class);  
      // invoke code to be tested...
  }
}

, @Test(expected=RuntimeException.class), : , . , , ( ), , .

Answer 3

:

public class SimpleDateFormatExampleTest {

    @SuppressWarnings("deprecation")
    @Test(expected=ParseException.class)
    public void testConvertStringToDate() throws ParseException {
        SimpleDateFormatExample simpleDateFormatExample = new SimpleDateFormatExample();

    Assert.assertNotNull(simpleDateFormatExample.convertStringToDate("08-16-2011"));

(expected=ParseException.class)

Assert.assertNotNull(simpleDateFormatExample.convertStringToDate("08/16/2011"));

    }

public class SimpleDateFormatExample {


    public Date convertStringToDate(String dateStr) throws ParseException{
        return new SimpleDateFormat("mm/DD/yyyy").parse(dateStr);
    }
}