@Test
public void should_return_preferred_instance() {
final DividendYieldCalculator common =
dividendYieldCalculatorFactory.newInstance(StockType.PREFERRED);
assertNotNull(common);
assertEquals(DividendYieldPreferredCalculatorImpl.class, common.getClass());
assertNotEquals(DividendYieldCommonCalculatorImpl.class, common.getClass());
}
@Test(expected = NullPointerException.class)
public void should_throw_null_pointer_exception() {
dividendYieldCalculatorFactory.newInstance(null);
}