@Test public void valid_id_should_return_null_file_name() { assertThat(loader.resolvePersonFileNameById("2"), is("person-2.txt")); assertThat(loader.resolvePersonFileNameById("4"), is("person-4.txt")); }
@Test(expected = IllegalArgumentException.class) public void null_id_should_should_throw_an_exception() { loader.resolvePersonFileNameById(null); }