@Override
  public void setEvaluation(EvaluatedQualityGate g) {
    // fail fast
    requireNonNull(g);
    checkState(evaluation == null, "QualityGateHolder evaluation can be initialized only once");

    this.evaluation = g;
  }
@Test
  public void setEvaluation_throws_NPE_if_argument_is_null() {
    assertThatThrownBy(() -> new QualityGateHolderImpl().setEvaluation(null))
      .isInstanceOf(NullPointerException.class);
  }