mono/mcs/class/System.Core/Test/System.Linq.Expressions/ExpressionTest_Lambda.cs

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//
// Authors:
//   Miguel de Icaza ([email protected])

using System;
using System.Reflection;
using System.Linq;
using System.Linq.Expressions;
using NUnit.Framework;

namespace MonoTests.System.Linq.Expressions
{
	[TestFixture]
	public class ExpressionTest_Lambda
	{
		[Test]
		[ExpectedException (typeof (ArgumentException))]
		public void NonDelegateTypeInCtor ()
		{
			// The first parameter must be a delegate type
			Expression.Lambda (typeof(string), Expression.Constant (1), new ParameterExpression [0]);
		}

		delegate object delegate_object_emtpy ();
		delegate object delegate_object_int (int a);
		delegate object delegate_object_string (string s);
		delegate object delegate_object_object (object s);

		[Test]
		[ExpectedException (typeof (ArgumentException))]
		public void InvalidConversion ()
		{
			// float to object, invalid
			Expression.Lambda (typeof (delegate_object_emtpy), Expression.Constant (1.0), new ParameterExpression [0]);
		}

		[Test]
		[ExpectedException (typeof (ArgumentException))]
		public void InvalidConversion2 ()
		{
			// float to object, invalid
			Expression.Lambda (typeof (delegate_object_emtpy), Expression.Constant (1), new ParameterExpression [0]);
		}

		[Test]
		[ExpectedException (typeof (ArgumentException))]
		public void InvalidArgCount ()
		{
			// missing a parameter
			Expression.Lambda (typeof (delegate_object_int), Expression.Constant ("foo"), new ParameterExpression [0]);
		}

		[Test]
		[ExpectedException (typeof (ArgumentException))]
		public void InvalidArgCount2 ()
		{
			// extra parameter
			ParameterExpression p = Expression.Parameter (typeof (int), "AAA");
			Expression.Lambda (typeof (delegate_object_emtpy), Expression.Constant ("foo"), new ParameterExpression [1] {p});
		}

		[Test]
		[ExpectedException (typeof (ArgumentException))]
		public void InvalidArgType ()
		{
			// invalid argument type
			
			ParameterExpression p = Expression.Parameter (typeof (string), "AAA");
			Expression.Lambda (typeof (delegate_object_int), Expression.Constant ("foo"), new ParameterExpression [1] {p});
		}

		[Test]
		[ExpectedException (typeof (ArgumentException))]
		public void InvalidArgType2 ()
		{
			// invalid argument type
			
			ParameterExpression p = Expression.Parameter (typeof (string), "AAA");
			Expression.Lambda (typeof (delegate_object_object), Expression.Constant ("foo"), new ParameterExpression [1] {p});
		}
		
		[Test]
		public void Assignability ()
		{
			// allowed: string to object
			Expression.Lambda (typeof (delegate_object_emtpy), Expression.Constant ("string"), new ParameterExpression [0]);

			// allowed delegate has string, delegate has base class (object)
			ParameterExpression p = Expression.Parameter (typeof (object), "ParObject");
			Expression.Lambda (typeof (delegate_object_string), Expression.Constant (""), new ParameterExpression [1] {p});
		}

		[Test]
		public void Compile ()
		{
			Expression<Func<int>> l = Expression.Lambda<Func<int>> (Expression.Constant (1), new ParameterExpression [0]);
			Func<int> fi = l.Compile ();
			fi ();
		}
	}
}