Soak beans overnight in cold water.
Heat olive oil in a large pot, add onion and garlic and cook until soft. Add drained beans and boiling broth or water, cover and cook gently for one hour. Add tomatoes and simmer, covered, for another hour.
Remove about half the beans and mash them, then return the paste to the soup, along with the pasta. Cook for 10 or 15 minutes until pasta