public void AddDiplomaReturnsDiploma()
{
//Arrange
diplomaRepository.Setup(d => d.Post(It.IsAny <Diploma>())).ReturnsAsync((Diploma d) => { return(d); });
long doctorId = 1;
//Act
var result = (controller.AddDiplomaToDoctor(doctorId, new Diploma()).Result as OkObjectResult).Value;
//Assert
Assert.IsInstanceOfType(result, typeof(Diploma));
Assert.AreEqual(doctorId, (result as Diploma)?.DoctorId);
}