Chess Software to Drill Repertoire Positions (not lines)

I'm looking for software to drill my opening repertoire.  Specifically:

• I input the repertoire
• The software randomly sorts the positions in the lines and presents them one by one (in random order), and I test myself

Most repertoire software I've seen is based on lines of play - it quizzes you move by move in sequential order.  That's a fine approach but I'd like to supplement it by using flashcard-like quizzing of the positions in random order.  That way if I arrive at something by transposition, I know what to play and I'm less reliant on memorizing specific move orders, etc.

I'd prefer iOS, then Mac as a second choice, and Windows as a third choice...if this software exists.

None of my GUI programs have a "create a set of positions and quiz them like flashcards" feature.  Which program are you thinking of that has this feature?