Test\TestCase not found

Hi - I'm trying to write a basic test in Laravel, but am getting the error: Uncaught Error: Class "Tests\TestCase" not found in C:\xampp\htdocs\tdrwip\tests\Feature\Libraries\LibraryIndexTest.php:9. Here's the code:

<?php

namespace Tests\Feature\Libraries;

use Illuminate\Foundation\Testing\RefreshDatabase;
use Illuminate\Foundation\Testing\WithFaker;
use Tests\TestCase;

class LibraryIndexTest extends TestCase
{
    /**
     * A basic feature test example.
     *
     * @return void
     */
    public function test_example()
    {
        $response = $this->get('/');

        $response->assertStatus(200);
    }
}

Using phpstorm, when I right-click the TestCase -> GoTo -> Super Method, nothing happens. My tests directory is: /tests

• Feature
• Unit
• CreatesApplication.php
• TestCase.php

My composer.json includes: "autoload-dev": { "psr-4": { "Tests\": "tests/" } I'm on Laravel 8.83.6. Has anyone else run into this and found a cause/fix? Thanks! },