System.accessviolationexception in nunit test

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C#

.NET

NUnit

I'm using Visual Studio 2012 / C# with nUnit test, and get System.AccessViolationException on simple test...

When I launch the "Execute Test" option, the test returns OK.
When I launch the "Debug Test" option, I get System.AccessViolationException.

I think something in my config is not good. I'm pretty sure the source is good and has no hidden bug.

Any help will help.

Here is the code :

Class1.cs

using System;

namespace ClassLibrary1
{
    public class Class1
    {
        public String test = "1";
        public Class1()
        {
        }

        public void Test()
        {
            test = "2";
        }
    }
}

UnitTest1.cs

using ClassLibrary1;
using NUnit.Framework;


namespace UnitTestProject1
{
    [TestFixture]
    public class UnitTest1
    {
        [Test]
        public void TestMethod1()
        {
            Class1 classe = new Class1();
            Assert.AreEqual(classe.test, "1");
            classe.Test();
            Assert.AreEqual(classe.test, "2");
        }
    }
}

What I have tried:

Try to reinstall VS2012 + nUnit with no success.