JUnit Exception Testing

External

• https://github.com/junit-team/junit4/wiki/Exception-testing

Internal

• JUnit

Idioms

Try/Catch

try {
  ...
  fail("should have thrown exception");
}
catch(SomeException e) {

  assertEquals("some message", e.getMessage());
}

assertThrows()

@Test
public void testExceptionAndState() {
  List<Object> list = new ArrayList<>();

  IndexOutOfBoundsException thrown = assertThrows(
      IndexOutOfBoundsException.class,
      () -> list.add(1, new Object()));

  // assertions on the thrown exception
  assertEquals("Index: 1, Size: 0", thrown.getMessage());
  // assertions on the state of a domain object after the exception has been thrown
  assertTrue(list.isEmpty());
}

Annotation Attributes

@Test(expected = ArrayIndexOutOfBoundsException.class)
public void testSomething() {
  ...
}