public void KeyCollection(JaggedDictionary<int, string> sut, KeyValuePair<JaggedIndex4<int>, string>[] values)
        {
            foreach (var kvp in values) sut[kvp.Key] = kvp.Value;

            var debugView = new JaggedDictionaryKeyCollectionDebugView<int, string>(sut.Keys);
            var items = debugView.Items;
            Assert.Equal(values.Select(kvp => kvp.Key).Distinct().Count(), items.Length);
        }
        public void KeyCollection(JaggedDictionary <int, string> sut, KeyValuePair <JaggedIndex4 <int>, string>[] values)
        {
            foreach (var kvp in values)
            {
                sut[kvp.Key] = kvp.Value;
            }

            var debugView = new JaggedDictionaryKeyCollectionDebugView <int, string>(sut.Keys);
            var items     = debugView.Items;

            Assert.Equal(values.Select(kvp => kvp.Key).Distinct().Count(), items.Length);
        }