Easy Italian Sausage Spaghetti
1 (16 ounce) package spaghetti, or as needed 1 (6 ounce) can sliced black olives, drained 1 (6 ounce) can tomato paste 1 green bell pepper, chopped 1 onion, chopped 1 pound fresh mushrooms, sliced 1 tablespoon minced garlic 1 tablespoon olive oil 1 teaspoon dried basil, or to taste 1 teaspoon dried oregano, or to taste 2 (28 ounce) cans tomato sauce 2 pounds sweet Italian sausage 2 tomatoes, diced salt to taste ¼ cup grated Parmesan cheese, or to taste