Cook the pasta until al dente. Drain, return to the pan, & toss over a low heat with the oil, beans & garlic, to warm through. Remove from the heat & stir in the pesto. Serve imemdiately. VARIATION: Instead of ditalini, choose a flat pasta such as fettuccine & add a handful of green beans cut into bite-sized pieces, to the boiuling water when the pasta is half cooked. If yellow wax beans are available, add them too. Toss with the rest of the ingredients as above.