    @Test
    public void shouldReadLongValue() {

        AtomicLong value = new AtomicLong(0);
        observer.onLongValue("test", 11L, value::set);
        assertThat(value.get()).isEqualTo(11L);
        writeConfigLine("test = 1337");
        assertThat(value.get()).isEqualTo(1337L);
    }