public virtual void TestEquals() { TreeShapedStack <string> t1 = new TreeShapedStack <string>(); t1 = t1.Push("foo"); t1 = t1.Push("bar"); t1 = t1.Push("bar"); t1 = t1.Push("diet"); t1 = t1.Push("coke"); TreeShapedStack <string> t2 = new TreeShapedStack <string>(); t2 = t2.Push("foo"); t2 = t2.Push("bar"); t2 = t2.Push("bar"); t2 = t2.Push("diet"); t2 = t2.Push("coke"); TreeShapedStack <string> t3 = t2.Pop().Push("pepsi"); NUnit.Framework.Assert.AreEqual(t1, t2); NUnit.Framework.Assert.IsFalse(t1.Pop().Equals(t2)); NUnit.Framework.Assert.IsFalse(t2.Pop().Equals(t1)); NUnit.Framework.Assert.IsFalse(t2.Equals(t3)); }