public void supporterAddNullChildReturnsNull()
    {
      Supporter supporter = new Supporter("table");
      var item = supporter.AddChild(null);

      Assert.That(item, Is.Null);
    }
    public void supporterHasChildrenReturnsTrueIfChildren()
    {
      Supporter supporter = new Supporter("table");
      var entity = new Thing("cup");
      var item = supporter.AddChild(entity);

      Assert.That(supporter.HasChildren(), Is.True);
    }
    public void supporterAddChildReturnsChild()
    {
      Supporter supporter = new Supporter("table");
      var entity = new Thing("cup");
      var item = supporter.AddChild(entity);

      Assert.That(item.SameIdentityAs(entity), Is.True);
    }
    public void supporterGetChildrenReturnsChildren()
    {
      Supporter supporter = new Supporter("table");
      var entity = new Thing("cup");
      var item = supporter.AddChild(entity);

      var children = supporter.GetChildren();
      Assert.That(children.First().SameIdentityAs(item), Is.True);
    }