public void ItShouldReturnExpectedValue(RotorCraft rotorCraft) { engineaddition.Setup(dec => dec.AddTurboshaftEngines(It.IsAny<RotorCraft>())).Returns(() => rotorCraft); var somecraft = heavierThanAirAircraftFactory.TryMakeRotorCraft(rotorCraft.SerialNumber, rotorCraft.RotorBlades.ToList(), "singular", 2, 56, "linx", 12000); Assert.AreEqual(rotorCraft.ToString(), somecraft.ToString()); }