public void Evaluation_Throws_Exception_On_Variable_Encounter()
{
var variableExpression = new Variable()
{
Name = "a"
};
var visitor = new EvaluatingExpressionVisitor();
Action a = () => visitor.Evaluate(variableExpression, null);
a.ShouldThrow <InvalidOperationException>();
}
public void EvaluateReplacesExpressionsWithConstantExpressions()
{
Expression <Func <DateTime> > call = () => DateTime.Now.Subtract(TimeSpan.FromHours(5));
var nodeToEvaluate = FlatteningExpressionVisitor.Flatten(call).OfType <MethodCallExpression>().Single(s => s.Method.Name == "FromHours");
var evaluation = EvaluatingExpressionVisitor.Evaluate(call, new HashSet <Expression>(new[] { nodeToEvaluate }));
var constantNodes = FlatteningExpressionVisitor.Flatten(evaluation).OfType <ConstantExpression>().ToArray();
Assert.Equal(1, constantNodes.Length);
Assert.Equal(TimeSpan.FromHours(5), constantNodes.Single().Value);
}
