public void SourceWithSingleValue_ReturnsJustCurrent()
{
var iterator = EnumerableEx.Return(0).ToPrevNextIterator();
var standard = new[] { new PrevNextValue <int>(Optional <int> .None, 0, Optional <int> .None) };
CollectionAssert.AreEqual(iterator, standard);
}
static IEnumerable <IEnumerable <T> > SplitWithBordersIterator <T>(IEnumerable <T> source,
Relation <T, T, T> relation)
{
List <T> acc;
using (var enumerator = source.GetEnumerator())
{
if (!enumerator.MoveNext())
{
yield break;
}
T first = enumerator.Current;
if (!enumerator.MoveNext())
{
yield return(EnumerableEx.Return(first));
yield break;
}
T second = enumerator.Current;
acc = new List <T> {
first, second
};
while (enumerator.MoveNext())
{
T item = enumerator.Current;
if (relation(first, second, item))
{
acc.Add(item);
}
else
{
yield return(acc);
acc = new List <T> {
second, item
};
}
first = second;
second = item;
}
}
if (acc.Count > 0)
{
yield return(acc);
}
}
public void Except_OnlyTargetItem_ReturnsEmpty()
{
var items = EnumerableEx.Return(0);
CollectionAssert.IsEmpty(items.Except(0));
}
public static IEnumerable <T> Generate <T>(T state, Predicate <T> condition, Func <T, T> iterate)
{
return(EnumerableEx.Generate(state, x => condition(x), iterate, Functions.Identity <T>()));
}