Preheat oven to 425°F (220°C). Combine parsley, sun-dried tomatoes, oil, garlic, Italian seasoning, salt and pepper in a blender or food processor. Blend until smooth

Combine tomatoes, yellow pepper and squash in a small roasting pan and toss with half the pesto mixture. Push to one side of pan; add sausages to the other side of pan.

Roast for 40 minutes. Remove sausages to a board and slice thinly. Stir beans into vegetable mixture; roast for an additional 5 minutes.

Meanwhile, cook spaghetti according to package directions.

Add hot spaghetti, sliced sausages and remaining pesto mixture to roasting pan; toss to combine.