public void ReduceNumberOfContracts() { Organisation organisation; organisation = Repository.FindOrganisationById(OrganisationId); ushort?previousNumberOfContracts = organisation.NumberOfContracts; Repository.DecreaseNumberOfContracts(OrganisationId); organisation = Repository.FindOrganisationById(OrganisationId); Assert.Less(organisation.NumberOfContracts, previousNumberOfContracts); }