Heat the oil in a pot over medium heat. Add garlic and onion; cook and stir for about 5 minutes. Add the sausage, breaking into small pieces. Cook and stir for another 5 minutes, or until browned.
Stir in the beans, tomatoes with their juice and chicken broth. Season with rosemary and black pepper. Bring to a simmer, and cook for at least 10 minutes. Serve right away, or let it simmer for a while, stirring occasionally, until you are ready to eat.
