mono/mcs/class/System.Core/Test/System.Linq.Expressions/ExpressionTest_Field.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_Field
	{
		[Test]
		[ExpectedException (typeof (ArgumentNullException))]
		public void Arg1Null ()
		{
			Expression.Field (null, "NoField");
		}

		[Test]
		[ExpectedException (typeof (ArgumentNullException))]
		public void Arg2Null1 ()
		{
			Expression.Field (Expression.Constant (new MemberClass()), (string)null);
		}

		[Test]
		[ExpectedException (typeof (ArgumentNullException))]
		public void Arg2Null2 ()
		{
			Expression.Field (Expression.Constant (new MemberClass()), (FieldInfo)null);
		}

		[Test]
		[ExpectedException (typeof (ArgumentException))]
		public void NoField ()
		{
			Expression.Field (Expression.Constant (new MemberClass()), "NoField");
		}

		[Test]
		public void InstanceField ()
		{
			MemberExpression expr = Expression.Field (Expression.Constant (new MemberClass()), "TestField1");
			Assert.AreEqual (ExpressionType.MemberAccess, expr.NodeType, "Field#01");
			Assert.AreEqual (typeof (int), expr.Type, "Field#02");
			Assert.AreEqual ("value(MonoTests.System.Linq.Expressions.MemberClass).TestField1", expr.ToString(), "Field#03");
		}

		[Test]
		[ExpectedException (typeof (ArgumentException))]
		public void StaticField1 ()
		{
			// This will fail because access to a static field should be created using a FieldInfo and
			// not an instance plus the field name.
			Expression.Field (Expression.Constant (new MemberClass()), "StaticField");
		}

		[Test]
		public void StaticField2 ()
		{
			MemberExpression expr = Expression.Field (null, MemberClass.GetStaticFieldInfo());
			Assert.AreEqual (ExpressionType.MemberAccess, expr.NodeType, "Field#07");
			Assert.AreEqual (typeof (int), expr.Type, "Field#08");
			Assert.AreEqual ("MemberClass.StaticField", expr.ToString(), "Field#09");
		}

		public static string foo = "foo";

		[Test]
		public void CompileStaticField ()
		{
			var foo = Expression.Lambda<Func<string>> (
				Expression.Field (null, GetType ().GetField (
					"foo", BindingFlags.Static | BindingFlags.Public))).Compile ();

			Assert.AreEqual ("foo", foo ());
		}

		public class Bar {
			public string baz;

			public Bar ()
			{
				baz = "baz";
			}
		}

		[Test]
		public void CompileInstanceField ()
		{
			var p = Expression.Parameter (typeof (Bar), "bar");
			var baz = Expression.Lambda<Func<Bar, string>> (
				Expression.Field (p, typeof (Bar).GetField (
					"baz", BindingFlags.Public | BindingFlags.Instance)), p).Compile ();

			Assert.AreEqual ("baz", baz (new Bar ()));
		}

		public struct Gazonk {
			public string Tzap;

			public Gazonk (string tzap)
			{
				Tzap = tzap;
			}
		}

		[Test]
		public void CompileStructInstanceField ()
		{
			var p = Expression.Parameter (typeof (Gazonk), "gazonk");
			var gazonker = Expression.Lambda<Func<Gazonk, string>> (
				Expression.Field (p, typeof (Gazonk).GetField ("Tzap")), p).Compile ();

			Assert.AreEqual ("bang", gazonker (new Gazonk ("bang")));
		}
	}
}