public void CreateExpression_TwoChildExpressionAndPlusOperator_Sum()
        {
            var children = new Expression[] { };
            var term = new NumberTerm(10.0);

            var expression = term.CreateExpression(children);
            var lambda = Expression.Lambda<Func<double>>(expression);

            Assert.That(lambda.Compile()(), Is.EqualTo(10.0).Within(1e-5));
        }
 public void Number_SomeValue_Equal()
 {
     var number = 3.7;
     var term = new NumberTerm(number);
     Assert.That(term.Number, Is.EqualTo(number));
 }