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

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// Authors:
//		Federico Di Gregorio <[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_Subtract
	{
		[Test]
		[ExpectedException (typeof (ArgumentNullException))]
		public void Arg1Null ()
		{
			Expression.Subtract (null, Expression.Constant (1));
		}

		[Test]
		[ExpectedException (typeof (ArgumentNullException))]
		public void Arg2Null ()
		{
			Expression.Subtract (Expression.Constant (1), null);
		}

		[Test]
		[ExpectedException (typeof (InvalidOperationException))]
		public void ArgTypesDifferent ()
		{
			Expression.Subtract (Expression.Constant (1), Expression.Constant (2.0));
		}

		[Test]
		[ExpectedException (typeof (InvalidOperationException))]
		public void NoOperatorClass ()
		{
			Expression.Subtract (Expression.Constant (new NoOpClass ()), Expression.Constant (new NoOpClass ()));
		}

		[Test]
		[ExpectedException (typeof (InvalidOperationException))]
		public void Boolean ()
		{
			Expression.Subtract (Expression.Constant (true), Expression.Constant (false));
		}

		[Test]
		public void Numeric ()
		{
			BinaryExpression expr = Expression.Subtract (Expression.Constant (1), Expression.Constant (2));
			Assert.AreEqual (ExpressionType.Subtract, expr.NodeType, "Subtract#01");
			Assert.AreEqual (typeof (int), expr.Type, "Subtract#02");
			Assert.IsNull (expr.Method, "Subtract#03");
			Assert.AreEqual ("(1 - 2)", expr.ToString(), "Subtract#04");
		}

		[Test]
		public void Nullable ()
		{
			int? a = 1;
			int? b = 2;

			BinaryExpression expr = Expression.Subtract (Expression.Constant (a), Expression.Constant (b));
			Assert.AreEqual (ExpressionType.Subtract, expr.NodeType, "Subtract#05");
			Assert.AreEqual (typeof (int), expr.Type, "Subtract#06");
			Assert.IsNull (expr.Method, "Subtract#07");
			Assert.AreEqual ("(1 - 2)", expr.ToString(), "Subtract#08");
		}

		[Test]
		public void UserDefinedClass ()
		{
			// We can use the simplest version of GetMethod because we already know only one
			// exists in the very simple class we're using for the tests.
			MethodInfo mi = typeof (OpClass).GetMethod ("op_Subtraction");

			BinaryExpression expr = Expression.Subtract (Expression.Constant (new OpClass ()), Expression.Constant (new OpClass ()));
			Assert.AreEqual (ExpressionType.Subtract, expr.NodeType, "Subtract#09");
			Assert.AreEqual (typeof (OpClass), expr.Type, "Subtract#10");
			Assert.AreEqual (mi, expr.Method, "Subtract#11");
			Assert.AreEqual ("op_Subtraction", expr.Method.Name, "Subtract#12");
			Assert.AreEqual ("(value(MonoTests.System.Linq.Expressions.OpClass) - value(MonoTests.System.Linq.Expressions.OpClass))",
				expr.ToString(), "Subtract#13");
		}

		[Test]
		public void CompileSubtract ()
		{
			var left = Expression.Parameter (typeof (int), "l");
			var right = Expression.Parameter (typeof (int), "r");
			var l = Expression.Lambda<Func<int, int, int>> (
				Expression.Subtract (left, right), left, right);

			var be = l.Body as BinaryExpression;
			Assert.IsNotNull (be);
			Assert.AreEqual (typeof (int), be.Type);
			Assert.IsFalse (be.IsLifted);
			Assert.IsFalse (be.IsLiftedToNull);

			var c = l.Compile ();

			Assert.AreEqual (0, c (6, 6));
			Assert.AreEqual (-2, c (-1, 1));
			Assert.AreEqual (4, c (1, -3));
		}
	}
}