public void Keys_WhenDataIsNotEmpty_ShowsEveryKey() { _hash.Set("Lucas", 1); _hash.Set("Sephiroth", 2); _hash.Set("Jenn", 3); _hash.Set("Tifa", 4); var correctList = new List <string> { "Lucas", "Sephiroth", "Jenn", "Tifa" }; Assert.That(_hash.Keys(), Is.EquivalentTo(correctList)); }