public void WithAppearance_WhenCalled_SetsAppearance()
        {
            // Arrange
            var  fakeItem = new FakeItem();
            Item item     = fakeItem;

            var appearance = Substitute.For <ItemAppearance>(item);

            // Act
            fakeItem.WithAppearance(appearance);

            // Assert
            item.Appearance.Should().NotBeNull();
        }