private void RunToDictionaryOnAllCollectionTypes <T>(T[] items, Action <Dictionary <T, T> > validation)
{
validation(Enumerable.ToDictionary(items, key => key));
validation(Enumerable.ToDictionary(items, key => key, value => value));
validation(Enumerable.ToDictionary(new List <T>(items), key => key));
validation(Enumerable.ToDictionary(new List <T>(items), key => key, value => value));
validation(new TestEnumerable <T>(items).ToDictionary(key => key));
validation(new TestEnumerable <T>(items).ToDictionary(key => key, value => value));
validation(new TestReadOnlyCollection <T>(items).ToDictionary(key => key));
validation(new TestReadOnlyCollection <T>(items).ToDictionary(key => key, value => value));
validation(new TestCollection <T>(items).ToDictionary(key => key));
validation(new TestCollection <T>(items).ToDictionary(key => key, value => value));
}