/mcs/class/System.Core/Test/System.Linq.Expressions/ExpressionTest_Constant.cs

// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
//
// Authors:
//		Federico Di Gregorio <fog@initd.org>

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

namespace MonoTests.System.Linq.Expressions
{
	[TestFixture]
	public class ExpressionTest_Constant
	{
		[Test]
		[ExpectedException (typeof (ArgumentException))]
		public void Arg2NotNullable ()
		{
			Expression.Constant(null, typeof(int));
		}

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

		[Test]
		public void NullValue ()
		{
			ConstantExpression expr = Expression.Constant (null);
			Assert.AreEqual (ExpressionType.Constant, expr.NodeType, "Constant#01");
			Assert.IsNull (expr.Value, "Constant#02");
			Assert.AreEqual (typeof (object), expr.Type, "Constant#03");
			Assert.AreEqual ("null", expr.ToString(), "Constant#04");
		}

		[Test]
		public void NullableValue1 ()
		{
			ConstantExpression expr = Expression.Constant (null, typeof(int?));
			Assert.AreEqual (ExpressionType.Constant, expr.NodeType, "Constant#05");
			Assert.IsNull (expr.Value, "Constant#06");
			Assert.AreEqual (typeof (int?), expr.Type, "Constant#07");
			Assert.AreEqual ("null", expr.ToString(), "Constant#08");
		}

		[Test]
		public void NullableValue2 ()
		{
			ConstantExpression expr = Expression.Constant (1, typeof (int?));
			Assert.AreEqual (ExpressionType.Constant, expr.NodeType, "Constant#09");
			Assert.AreEqual (1, expr.Value, "Constant#10");
			Assert.AreEqual (typeof (int?), expr.Type, "Constant#11");
			Assert.AreEqual ("1", expr.ToString(), "Constant#12");
		}

		[Test]
		public void NullableValue3 ()
		{
			ConstantExpression expr = Expression.Constant ((int?)1);
			Assert.AreEqual (ExpressionType.Constant, expr.NodeType, "Constant#13");
			Assert.AreEqual (1, expr.Value, "Constant#14");
			Assert.AreEqual (typeof (int), expr.Type, "Constant#15");
			Assert.AreEqual ("1", expr.ToString(), "Constant#16");
		}

		[Test]
		public void IntegerValue ()
		{
			ConstantExpression expr = Expression.Constant (0);
			Assert.AreEqual (ExpressionType.Constant, expr.NodeType, "Constant#17");
			Assert.AreEqual (0, expr.Value, "Constant#18");
			Assert.AreEqual (typeof (int), expr.Type, "Constant#19");
			Assert.AreEqual ("0", expr.ToString(), "Constant#20");
		}

		[Test]
		public void StringValue ()
		{
			ConstantExpression expr = Expression.Constant ("a string");
			Assert.AreEqual (ExpressionType.Constant, expr.NodeType, "Constant#21");
			Assert.AreEqual ("a string", expr.Value, "Constant#22");
			Assert.AreEqual (typeof (string), expr.Type, "Constant#23");
			Assert.AreEqual ("\"a string\"", expr.ToString(), "Constant#24");
		}

		[Test]
		public void DateTimeValue ()
		{
			ConstantExpression expr = Expression.Constant (new DateTime(1971, 10, 19));
			Assert.AreEqual (ExpressionType.Constant, expr.NodeType, "Constant#25");
			Assert.AreEqual (new DateTime(1971, 10, 19), expr.Value, "Constant#26");
			Assert.AreEqual (typeof (DateTime), expr.Type, "Constant#27");
			Assert.AreEqual (new DateTime(1971, 10, 19).ToString(), expr.ToString(), "Constant#28");
		}

		[Test]
		public void UserClassValue ()
		{
			OpClass oc = new OpClass ();
			ConstantExpression expr = Expression.Constant (oc);
			Assert.AreEqual (ExpressionType.Constant, expr.NodeType, "Constant#29");
			Assert.AreEqual (oc, expr.Value, "Constant#30");
			Assert.AreEqual (typeof (OpClass), expr.Type, "Constant#31");
			Assert.AreEqual ("value(MonoTests.System.Linq.Expressions.OpClass)", expr.ToString(), "Constant#32");
		}

		[Test]
		[ExpectedException (typeof (ArgumentException))]
		public void TestInvalidCtor_1 ()
		{
			// null value, type == valuetype is invalid
			Expression.Constant (null, typeof (int));
		}

		[Test]
		[ExpectedException (typeof (ArgumentException))]
		public void TestInvalidCtor_2 ()
		{
			// type mismatch: int value, type == double
			Expression.Constant (0, typeof (double));
		}

		[Test]
		[ExpectedException (typeof (ArgumentException))]
		public void VoidConstant ()
		{
			Expression.Constant (null, typeof (void));
		}

		static T Check<T> (T val)
		{
			Expression<Func<T>> l = Expression.Lambda<Func<T>> (Expression.Constant (val), new ParameterExpression [0]);
			Func<T> fi = l.Compile ();
			return fi ();
		}

		[Test]
		public void NullableConstant_ToConstant ()
		{
			int? a = 1;
			ConstantExpression c = Expression.Constant (a);
			Assert.AreEqual (typeof (int), c.Type, "#1");
			Assert.AreEqual (1, c.Value, "#2");
		}

		[Test]
		public void ConstantCodeGen ()
		{
			Assert.AreEqual (Check<int> (0), 0, "int");
			Assert.AreEqual (Check<int> (128), 128, "int2");
			Assert.AreEqual (Check<int> (-128), -128, "int3");
			Assert.AreEqual (Check<int> (Int32.MinValue), Int32.MinValue, "int4");
			Assert.AreEqual (Check<int> (Int32.MaxValue), Int32.MaxValue, "int5");
			Assert.AreEqual (Check<uint> (128), 128, "uint");
			Assert.AreEqual (Check<uint> (0), 0, "uint2");
			Assert.AreEqual (Check<uint> (UInt32.MinValue), UInt32.MinValue, "uint3");
			Assert.AreEqual (Check<uint> (UInt32.MaxValue), UInt32.MaxValue, "uint4");
			Assert.AreEqual (Check<byte> (10), 10, "byte");
			Assert.AreEqual (Check<byte> (Byte.MinValue), Byte.MinValue, "byte2");
			Assert.AreEqual (Check<byte> (Byte.MaxValue), Byte.MaxValue, "byte3");
			Assert.AreEqual (Check<short> (128), 128, "short");
			Assert.AreEqual (Check<short> (-128), -128, "short");
			Assert.AreEqual (Check<short> (Int16.MinValue), Int16.MinValue, "short2");
			Assert.AreEqual (Check<short> (Int16.MaxValue), Int16.MaxValue, "short3");
			Assert.AreEqual (Check<ushort> (128), 128, "ushort");
			Assert.AreEqual (Check<ushort> (UInt16.MinValue), UInt16.MinValue, "short2");
			Assert.AreEqual (Check<ushort> (UInt16.MaxValue), UInt16.MaxValue, "short3");
			Assert.AreEqual (Check<bool> (true), true, "bool1");
			Assert.AreEqual (Check<bool> (false), false, "bool2");
			Assert.AreEqual (Check<long> (Int64.MaxValue), Int64.MaxValue, "long");
			Assert.AreEqual (Check<long> (Int64.MinValue), Int64.MinValue, "long2");
			Assert.AreEqual (Check<ulong> (UInt64.MaxValue), UInt64.MaxValue, "ulong");
			Assert.AreEqual (Check<ulong> (UInt64.MinValue), UInt64.MinValue, "ulong2");
			Assert.AreEqual (Check<ushort> (200), 200, "ushort");
			Assert.AreEqual (Check<float> (2.0f), 2.0f, "float");
			Assert.AreEqual (Check<double> (2.312), 2.312, "double");
			Assert.AreEqual (Check<string> ("dingus"), "dingus", "string");
			Assert.AreEqual (Check<decimal> (1.3m), 1.3m, "");

			// this forces the other code path for decimal.
			Assert.AreEqual (Check<decimal> (3147483647m), 3147483647m, "decimal");
		}

		delegate void Foo ();

		[Test]
		public void DelegateTypeConstant ()
		{
			Expression.Constant (typeof (Foo), typeof (Type));
		}

		[Test]
		public void EmitDateTimeConstant ()
		{
			var date = new DateTime (1983, 2, 6);

			var lambda = Expression.Lambda<Func<DateTime>> (Expression.Constant (date)).Compile ();

			Assert.AreEqual (date, lambda ());
		}

		[Test]
		public void EmitDBNullConstant ()
		{
			var lambda = Expression.Lambda<Func<DBNull>> (Expression.Constant (DBNull.Value)).Compile ();

			Assert.AreEqual (DBNull.Value, lambda ());
		}

		[Test]
		public void EmitNullString ()
		{
			var n = Expression.Lambda<Func<string>> (
				Expression.Constant (null, typeof (string))).Compile ();

			Assert.IsNull (n ());
		}

		[Test]
		public void EmitNullNullableType ()
		{
			var n = Expression.Lambda<Func<int?>> (
				Expression.Constant (null, typeof (int?))).Compile ();

			Assert.IsNull (n ());
		}

		interface IBar {}
		class Bar : IBar {}

		interface IBaz<T> {}
		class Baz<T> : IBaz<T> {}

		[Test]
		public void ConstantInterface ()
		{
			var c = Expression.Constant (new Bar (), typeof (IBar));
			Assert.AreEqual (typeof (IBar), c.Type);
		}

		[Test]
		public void ConstantGenericInterface ()
		{
			var c = Expression.Constant (new Baz<string> (), typeof (IBaz<string>));
			Assert.AreEqual (typeof (IBaz<string>), c.Type);
		}
	}
}