public void ExecuteBlock()
{
Machine machine = new Machine();
object nil = machine.UndefinedObjectClass;
Assert.IsNotNull(nil);
Assert.IsInstanceOfType(nil, typeof(IClass));
ModelParser parser = new ModelParser("nil ifNil: [GlobalName := 'foo']");
this.compiler.CompileExpression(parser.ParseExpression());
this.block.Execute(machine, null);
Assert.IsNotNull(machine.GetGlobalObject("GlobalName"));
}