Manual property customization

Infrastructure.cs

public class ExactPropertyCriterion : IEquatable<PropertyInfo>
{
    private readonly PropertyInfo propertyInfo;

    public ExactPropertyCriterion(PropertyInfo propertyInfo)
    {
        this.propertyInfo = propertyInfo;
    }

    public bool Equals(PropertyInfo other)
    {
        return this.propertyInfo?.Equals(other) == true;
    }
}

public class RequestRelay : ISpecimenBuilder
{
    private readonly IRequestSpecification specification;
    private readonly ISpecimenBuilder builder;

    public RequestRelay(IRequestSpecification specification, ISpecimenBuilder builder)
    {
        this.specification = specification;
        this.builder = builder;
    }

    public object Create(object request, ISpecimenContext context)
    {
        if (!this.specification.IsSatisfiedBy(request))
            return new NoSpecimen();

        return this.builder.Create(request, context);
    }
}

OrderTaxCustomization.cs

public class OrderTaxCustomization : ICustomization
{
    public void Customize(IFixture fixture)
    {
        fixture.Customizations.Add(
            new RequestRelay(
                new PropertySpecification(
                    new ExactPropertyCriterion(
                        typeof(Order).GetProperty(nameof(Order.Cost)))),
                new FixedBuilder(230)));
    }
}

OrderTests.cs

[Fact]
public void CustomizesProperty()
{
    var fixture = new Fixture().Customize(new OrderTaxCustomization());

    var order = fixture.Create<Order>();

    Assert.NotNull(order);
    Assert.Equal(230, order.TaxPercent);
}