Purée pesto ingredients in a food processor. This step can be done 1-2 days in advance.
Preheat oven to 425°F.
Cut off asparagus ends, cut stalks into 1-inch pieces.
Place on a cookie sheet. Add mushrooms to pan then spray with zero-calorie nonstick cooking spray and season with salt and pepper. Toss to coat veggies and place in oven.
Cook for 12-15 minutes, or until tender yet slightly crisp.
Cook fettuccine to package directions. When finished cooking, drain.
In a large bowl, combine pasta, roasted asparagus, mushrooms, pesto, and diced tomato. Stir to cover everything in pesto.