--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/HowTo/Aspects/NotNull.cs	Thu Mar 27 21:46:09 2014 +0400
@@ -0,0 +1,48 @@
+using System;
+
+using NUnit.Framework;
+
+using BLToolkit.Aspects;
+using BLToolkit.Reflection;
+
+namespace HowTo.Aspects
+{
+	[TestFixture]
+	public class NotNullTest
+	{
+		public /*[a]*/abstract/*[/a]*/ class TestObject
+		{
+			public /*[a]*/virtual/*[/a]*/ void Foo1(string str1, [/*[a]*/NotNull/*[/a]*/]              string str2, string str3) {}
+			public /*[a]*/virtual/*[/a]*/ void Foo2(string str1, [/*[a]*/NotNull/*[/a]*/(/*[a]*/"Null"/*[/a]*/)]      string str2, string str3) {}
+			public /*[a]*/virtual/*[/a]*/ void Foo3(string str1, [/*[a]*/NotNull/*[/a]*/(/*[a]*/"Null: {0}"/*[/a]*/)] string str2, string str3) {}
+
+			public static TestObject CreateInstance() { return /*[a]*/TypeAccessor/*[/a]*/<TestObject>.CreateInstance(); }
+		}
+
+		[Test, ExpectedException(typeof(ArgumentNullException))] // Error message is localized by framework.
+		public void Test1()
+		{
+			TestObject o = TestObject.CreateInstance();
+
+			o.Foo1("str1", /*[a]*/null/*[/a]*/, "str3");
+		}
+
+		[Test]
+		[ExpectedException(typeof(ArgumentNullException), ExpectedMessage="Null")]
+		public void Test2()
+		{
+			TestObject o = TestObject.CreateInstance();
+
+			o.Foo2("str1", /*[a]*/null/*[/a]*/, "str3");
+		}
+
+		[Test]
+		[ExpectedException(typeof(ArgumentNullException), ExpectedMessage="Null: str2")]
+		public void Test3()
+		{
+			TestObject o = TestObject.CreateInstance();
+
+			o.Foo3("str1", /*[a]*/null/*[/a]*/, "str3");
+		}
+	}
+}