it('should do type completion for joins', function () {
     let other = Enumerable.from(['a', 'aaa']);
     let actual: IEnumerable<string> = Enumerable
         .range(1, 4)
         .join(other, num => num, str => str.length, (num, len) => num + ':' + len);
     expect(actual.toJoinedString(',')).to.equal('1:a,3:aaa');
 });

  public static bestAndWorstMovies(movies: IEnumerable<Movie>): BestAndWorstMovies {
    if (!movies.any((m) => m.rating != null)) {
      return new BestAndWorstMovies([], []);
    }
    const bestMovieRating = movies.where((m) => m.rating !== null).max((m) => m.rating || 0);
    const worstMovieRating = movies.where((m) => m.rating !== null).min((m) => m.rating || 0);
    const bestMovies = movies.where((m) => m.rating === bestMovieRating).toArray();
    const worstMovies = movies.where((m) => m.rating === worstMovieRating).toArray();

    return new BestAndWorstMovies(bestMovies, worstMovies);
  }

 public static totalSharesByMovie(shares: IEnumerable<Share>, players: IEnumerable<Player>): number {
   return shares
     .where((s) => players.any((p) => p.id === s.playerId))
     .select((v) => v.numShares)
     .sum();
 }

 public static moviesForNewPage(movies: IEnumerable<Movie>): MovieNewDisplay[] {
   return movies.orderBy((movie) => movie.releaseDate).thenBy((movie) => movie.id).select(
     (movie) => new MovieNewDisplay(movie)).toArray();
 }

 public static maxEarningByMovie(earnings: IEnumerable<Earning>): number {
   const maxEarning = earnings.count() === 0 ? 0 :
     earnings.orderByDescending((e) => e.createdAt).first().gross;
   return maxEarning;
 }

 .where((s) => players.any((p) => p.id === s.playerId))