public void Equals()
        {
            CallExpression expr1 = new CallExpression("puts", new IExpression[] { new ConstantExpression(1) });
            CallExpression expr2 = new CallExpression("put", new IExpression[] { new ConstantExpression(1) });
            CallExpression expr3 = new CallExpression("puts", new IExpression[] { new ConstantExpression(2) });
            CallExpression expr4 = new CallExpression("puts", new IExpression[] { new ConstantExpression(2), new ConstantExpression(3) });
            CallExpression expr5 = new CallExpression("puts", new IExpression[] { new ConstantExpression(1) });

            Assert.IsTrue(expr1.Equals(expr5));
            Assert.IsTrue(expr5.Equals(expr1));
            Assert.AreEqual(expr1.GetHashCode(), expr5.GetHashCode());

            Assert.IsFalse(expr1.Equals(null));
            Assert.IsFalse(expr1.Equals(123));

            Assert.IsFalse(expr1.Equals(expr2));
            Assert.IsFalse(expr2.Equals(expr1));
            Assert.IsFalse(expr1.Equals(expr3));
            Assert.IsFalse(expr3.Equals(expr1));
            Assert.IsFalse(expr1.Equals(expr4));
            Assert.IsFalse(expr4.Equals(expr1));
        }