strict.cs

[Fact]
public void ReferInvalidApplications()
{
    Mock<IFrequentFlyerNumberValidator> mockValidator =
        new Mock<IFrequentFlyerNumberValidator>(MockBehavior.Strict);

    //mockValidator.Setup(x => x.IsValid(It.IsAny<string>())).Returns(false);

    var sut = new CreditApplicationEvaluator(mockValidator.Object);

    var application = new CreditApplication();

    CreditApplicationDecision decision = sut.Evaluate(application);

    Assert.Equal(CreditApplicationDecision.ReferredToHuman, decision);
}