Some helper classes to create a fake principal with roles

IdentityStub.cs

public class IdentityStub : IIdentity
{
	private readonly string _name;
	private readonly string _authenticationType;
	private readonly bool _isAuthenticated;

	public IdentityStub(string name, string authenticationType, bool isAuthenticated)
	{
		_name = name;
		_isAuthenticated = isAuthenticated;
		_authenticationType = authenticationType;
	}

	public string Name
	{
		get
		{
			return _name;
		}
	}

	public string AuthenticationType
	{
		get
		{
			return _authenticationType;
		}
	}

	public bool IsAuthenticated
	{
		get
		{
			return _isAuthenticated;
		}
	}
}

PrincipalStub.cs

public class PrincipalStub : IPrincipal
{
	private readonly string _name;
	private readonly string _authenticationType;
	private readonly bool _isAuthenticated;
	private readonly bool? _isInRoleResponse;
	private readonly List<string> _roles;

	public PrincipalStub(string name, string authenticationType, bool isAuthenticated, bool isInRoleResponse)
	{
		_name = name;
		_isAuthenticated = isAuthenticated;
		_authenticationType = authenticationType;
		_isInRoleResponse = isInRoleResponse;
	}

	public PrincipalStub(string name, string authenticationType, bool isAuthenticated, params string[] roles)
	{
		_name = name;
		_isAuthenticated = isAuthenticated;
		_authenticationType = authenticationType;
		_roles = new List<string>(roles);
	}

	public IIdentity Identity
	{
		get
		{
			return new IdentityStub(_name, _authenticationType, _isAuthenticated);
		}
	}

	public bool IsInRole(string role)
	{
		if (_isInRoleResponse.HasValue)
		{
			return _isInRoleResponse.Value;
		}

		return _roles.Contains(role);
	}
}

TestPrincipalManager.cs

public class TestPrincipalManager
{
	private PrincipalStub _principal;

	public TestPrincipalManager(string username, string authenticationType, bool isAuthenticated, params string[] roles)
	{
		_principal = new PrincipalStub(username, authenticationType, isAuthenticated, roles);
	}

	public TestPrincipalManager(string username, string authenticationType, bool isAuthenticated, bool isInRoleResponse)
	{
		_principal = new PrincipalStub(username, authenticationType, isAuthenticated, isInRoleResponse);
	}

	public IDisposable Attach()
	{
		IPrincipal originalPrincipal = Thread.CurrentPrincipal;
		Thread.CurrentPrincipal = _principal;
		return new TestPrincipalCleanup(originalPrincipal);
	}

	public class TestPrincipalCleanup : IDisposable
	{
		private readonly IPrincipal _principal;

		public TestPrincipalCleanup(IPrincipal principal)
		{
			_principal = principal;
		}

		public void Dispose()
		{
			Thread.CurrentPrincipal = _principal;
			GC.SuppressFinalize(this);
		}
	}
}

Usage.cs

var principalMan = new TestPrincipalManager("username", "authType", true, "PERMISSION_NAME");

using (principalMan.Attach())
{
    //principalpermission given
}