public void can_change_primary_location() { var subject = new Provider() { Id = 1 }; var locationA = new OrgUnit() { Id = 1 }; var providerLocationA = subject.AddOrgUnit(locationA); var locationB = new OrgUnit() { Id = 2 }; var providerLocationB = subject.AddOrgUnit(locationB); subject.SetPrimaryOrgUnit(providerLocationB); Assert.IsFalse(providerLocationA.IsPrimary.Value); Assert.IsTrue(providerLocationB.IsPrimary.Value); }