public void can_change_primary_specialty()
{
var subject = new Provider() { Id = 1 };
var specialtyA = new Specialty() { Id = 1 };
var providerSpecialtyA = subject.AddSpecialty(specialtyA);
var specialtyB = new Specialty() { Id = 2 };
var providerSpecialtyB = subject.AddSpecialty(specialtyB);
subject.SetPrimarySpecialty(providerSpecialtyB);
Assert.IsFalse(providerSpecialtyA.IsPrimary);
Assert.IsTrue(providerSpecialtyB.IsPrimary);
}
