public void AddPart_AfterBeginEditing_ChangesProportions() { // arrange var soil = new Soil() { Soil.Part <Sand>(1), Soil.Part <Turf>(3) }; // act soil.EndEdit(); soil.BeginEdit(); soil.Add <Sand>(2); // assert Assert.AreEqual(3, soil[SoilParts.Sand]); Assert.AreEqual(3, soil[SoilParts.Turf]); }