public void Removal()
{
GraphNode parent = new GraphNode();
GraphNode child = new GraphNode();
parent.AddDependent(child);
child.RemoveDepender(parent);
Assert.IsTrue( parent.Dependents.Length == 0 );
Assert.IsTrue( parent.Dependers.Length == 0 );
Assert.IsTrue( child.Dependers.Length == 0 );
Assert.IsTrue( child.Dependents.Length == 0 );
}
