public void Subtract_AddsNewNodeToElements(int add, Guid nodeId)
{
var counter = new PN_Counter(ImmutableHashSet <CounterElement> .Empty, ImmutableHashSet <CounterElement> .Empty);
counter = counter.Subtract(add, nodeId);
var element = counter.Subtractions.FirstOrDefault(e => e.Node.Id == nodeId);
Assert.Equal(add, element.Value);
}
public void Subtract_AddsToExistingElement(HashSet <CounterElement> existingElements, int add, Guid nodeId)
{
var existingElement = new CounterElement(999, nodeId);
existingElements.Add(existingElement);
var counter = new PN_Counter(ImmutableHashSet <CounterElement> .Empty, existingElements.ToImmutableHashSet());
counter = counter.Subtract(add, nodeId);
var element = counter.Subtractions.FirstOrDefault(e => e.Node.Id == nodeId);
Assert.Equal(999 + add, element.Value);
}