private void CompareLookups1(ILookup <string, int> look1, CachingDictionary <string, int> look2, HashSet <string> keys) { foreach (string k in keys) { Assert.Equal(look1.Contains(k), look2.Contains(k)); CheckEqualEnumerable(look1[k], look2[k]); } foreach (string k in new string[] { "goo", "bar", "banana", "flibber" }) { Assert.False(look1.Contains(k)); Assert.False(look2.Contains(k)); Assert.Empty(look1[k]); Assert.Empty(look2[k]); } }