einundzwanzig-portal/database/factories/CourseFactory.php

<?php

namespace Database\Factories;

use App\Models\Lecturer;
use Illuminate\Database\Eloquent\Factories\Factory;

class CourseFactory extends Factory
{
    /**
     * Define the model's default state.
     */
    public function definition(): array
    {
        return [
            'lecturer_id' => Lecturer::factory(),
            'name' => $this->faker->name(),
        ];
    }
}