public void CheckSumIsEmptyIfBBANwasNotCalc()
{
var sut = new GermanIBAN("85050300", "4000428549");
Assert.That(String.IsNullOrEmpty(sut.calcCheckSum()));
}
public void CheckSumIsCorrect()
{
var sut = new GermanIBAN("85050300", "4000428549");
sut.buildBBan();
Assert.That(sut.calcCheckSum() == "25");
}