public void IndexOf()
        {
            var layout1 = new CircularLayoutInfo {
                Radius = 1.0
            };
            var layout2 = new CircularLayoutInfo {
                Radius = 2.0
            };
            var layout3 = new CircularLayoutInfo {
                Radius = 3.0
            };
            var layout4 = new CircularLayoutInfo {
                Radius = 4.0
            };

            var fc    = new FrontChain();
            var node1 = fc.Add(layout1);
            var node2 = fc.Add(layout2);
            var node3 = fc.Add(layout3);
            var node4 = fc.Add(layout4);

            Assert.AreEqual(0, fc.IndexOf(node1));
            Assert.AreEqual(1, fc.IndexOf(node2));
            Assert.AreEqual(2, fc.IndexOf(node3));
            Assert.AreEqual(3, fc.IndexOf(node4));
        }
        public void IndexOf_OnlyHead()
        {
            var layout1 = new CircularLayoutInfo {
                Radius = 1.0
            };

            var fc    = new FrontChain();
            var node1 = fc.Add(layout1);

            Assert.AreEqual(0, fc.IndexOf(node1));
        }