public void Chaining_Dictionary() { var dict = new System.Collections.Generic.Dictionary <int, int> { [1] = 2, [3] = 4 }; var sortedDict = new System.Collections.Generic.SortedDictionary <int, int> { [1] = 2, [3] = 4 }; Assert.IsTrue(dict.SequenceEqual(dict.DefaultIfEmpty())); Assert.IsTrue(dict.SequenceEqual(dict.DefaultIfEmpty(dict.First()))); Assert.IsTrue(sortedDict.SequenceEqual(sortedDict.DefaultIfEmpty())); Assert.IsTrue(sortedDict.SequenceEqual(sortedDict.DefaultIfEmpty(sortedDict.First()))); }