public void FirstSequenceIsntAccessedBeforeFirstUse()
{
var first = new ThrowingEnumerable();
int[] second = { 5 };
// No exception yet...
var query = new ConcatEnumerable <ThrowingEnumerable, ThrowingEnumerable.Enumerator, ArrayEnumerable <int>, ArrayEnumerable <int> .Enumerator, int>(first, second.AsRefEnumerable());
// Still no exception...
using (var iterator = query.GetEnumerator())
{
// Now it will go bang
Assert.Throws <InvalidOperationException>(() => iterator.MoveNext());
}
}
public void SecondSequenceIsntAccessedBeforeFirstUse()
{
int[] first = { 5 };
var second = new ThrowingEnumerable();
// No exception yet...
var query = new ConcatEnumerable <ArrayEnumerable <int>, ArrayEnumerable <int> .Enumerator, ThrowingEnumerable, ThrowingEnumerable.Enumerator, int>(first.AsRefEnumerable(), second);
// Still no exception...
using (var iterator = query.GetEnumerator())
{
// First element is fine...
Assert.IsTrue(iterator.MoveNext());
Assert.AreEqual(5, iterator.Current);
// Now it will go bang, as we move into the second sequence
Assert.Throws <InvalidOperationException>(() => iterator.MoveNext());
}
}
