public void ShouldAllowInvestorToInvestOnlyOnce()
{
var venture = new Venture(new Name("Ventura"), new Amount(100), new Amount(1));
var investor = new Investor(new Name("investor"), new Amount(50000));
var duplicateInvestor = new Investor(new Name("investor"), new Amount(500));
venture.AddOffer(investor, new Amount(2));
Assert.Throws<InvalidOfferException>(() => venture.AddOffer(duplicateInvestor, new Amount(2)));
}