@Test
void recommendWrong() {

    final Participation p = mockParticipation(BigDecimal.TEN);
    final ParticipationDescriptor pd = new ParticipationDescriptor(p, () -> LOAN);
    final Optional<RecommendedParticipation> r = pd.recommend(p.getRemainingPrincipal()
        .subtract(1));
    assertThat(r).isEmpty();
}