private Test CreateRemoveItemsTest() { return(new TestCase("RemoveItems", () => { AssertDistinctIntancesNotEmpty(); var collection = GetSafeDefaultInstance(); var handler = new CollectionHandler <TCollection, TItem>(collection, Context); var initialContent = new ReadOnlyCollection <TItem>(new List <TItem>(collection)); foreach (var item in DistinctInstances) { if (!initialContent.Contains(item)) { handler.RemoveMissingItemFails(item); handler.AddSingleItemOk(item); } handler.RemoveItemOk(item); } })); }