public void Clear_HasComparer_ReturnsEmptyWithOriginalComparer()
        {
            ImmutableTrieDictionary <string, int> dictionary = new Dictionary <string, int>
            {
                { "a", 1 }
            }.ToImmutableTrieDictionary(StringComparer.OrdinalIgnoreCase);

            ImmutableTrieDictionary <string, int> clearedDictionary = dictionary.Clear();

            Assert.NotSame(ImmutableTrieDictionary <string, int> .Empty, clearedDictionary.Clear());
            Assert.NotEmpty(dictionary);

            clearedDictionary = clearedDictionary.Add("a", 1);
            Assert.True(clearedDictionary.ContainsKey("A"));
        }