public void ReceiveMessage()
{
Process process = new Process();
process.Tell(new Atom("ping"));
Process.Current = process;
MatchBody match = new MatchBody(new Atom("ping"), new ConstantExpression("pong"));
ReceiveExpression expr = new ReceiveExpression(new MatchBody[] { match });
Assert.IsFalse(expr.HasVariable());
var result = expr.Evaluate(null);
Assert.IsNotNull(result);
Assert.AreEqual("pong", result);
}