public void DistinctWithComparer()
{
DataProducer <string> subject = new DataProducer <string>();
IDataProducer <string> result = subject.Distinct(StringComparer.OrdinalIgnoreCase);
ProduceAndCheck(subject, result,
new[] { "zero", "one", "two", "one", "TWO", "three" },
new[] { "zero", "one", "two", "three" });
}