public void ContainsShouldReturnCorrectValue() { const string Value = "test value"; const string OtherValue = "other value"; var dict = new MultivalueDictionary<int, string>( () => new HashSet<string>() ); dict.Add( 1, Value ); dict.Add( 1, OtherValue ); Assert.True( dict.Contains( 1, Value ) ); Assert.False( dict.Contains( 1, Guid.NewGuid().ToString() ) ); }