public void CallTree_IntelligentExpand()
        {
            CallTree tree = CreateCallTree();

            tree.IntelligentExpand();

            tree.TopLevelNodes[0].IsExpanded.Should().BeTrue();
            tree.TopLevelNodes[0].Children[0].IsExpanded.Should().BeFalse();
            tree.TopLevelNodes[0].Children[1].IsExpanded.Should().BeTrue();
            tree.TopLevelNodes[0].Children[2].IsExpanded.Should().BeFalse();
            tree.TopLevelNodes[1].IsExpanded.Should().BeFalse();
            tree.TopLevelNodes[2].IsExpanded.Should().BeTrue();
        }