mono/mcs/class/corlib/Test/System.Threading/LazyInitializerTest.cs

//
// LazyInitializerTest.cs
//
// Authors:
//       Marek Safar ([email protected])
//
// Copyright 2011 Xamarin, Inc (http://www.xamarin.com)
//
// 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
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//


using System;
using System.Threading;
using NUnit.Framework;

namespace MonoTests.System.Threading
{
	[TestFixture]
	public class LazyInitializerTest
	{
		class C
		{
			public C ()
			{
				++Counter;
			}

			public int Counter { get; private set; }
		}

		[Test]
		public void EnsureInitialized_Simple ()
		{
			C c = null;
			c = LazyInitializer.EnsureInitialized (ref c);

			Assert.IsNotNull (c, "#1");
			Assert.AreEqual (1, c.Counter, "#2");
		}

		[Test]
		public void EnsureInitialized_FactoryIsNull ()
		{
			C c = null;
			try {
				LazyInitializer.EnsureInitialized (ref c, () => (C) null);
				Assert.Fail ();
			} catch (InvalidOperationException) {
			}
		}

		[Test]
		public void EnsureInitialized_NullLock ()
		{
			C c = null;
			bool init = false;
			object sync_lock = null;
			c = LazyInitializer.EnsureInitialized (ref c, ref init, ref sync_lock);

			Assert.IsNotNull (c, "#1");
			Assert.AreEqual (1, c.Counter, "#2");
			Assert.IsTrue (init, "#3");
			Assert.IsNotNull (sync_lock, "#4");

			var old_lock = sync_lock;
			var d = LazyInitializer.EnsureInitialized (ref c, ref init, ref sync_lock);

			Assert.AreEqual (c, d, "#11");
			Assert.AreEqual (1, c.Counter, "#12");
			Assert.IsTrue (init, "#13");
			Assert.AreEqual (old_lock, sync_lock, "#14");
		}
	}
}