I need help finding this movie!

I saw an edit of this one movie, which I've forgotten but I just remembered, so I apologize if the plot doesn't look so good. From what I remember, I think they were going to train(?) dogs, pit bulls specifically from what I remembered, but the presumably main character got a small pug instead. He thought it was going to grow bigger, but someone corrected him, telling him no. Aside from that, that's all I remember from the edit. Again, sorry if it's rather vague, but I sure hope someone can help me find this movie. Or show.