Laravel 5.4上的示例PHPUnit测试失败,带有404

我有一个测试：

<?php

namespace TestsFeature;

use TestsTestCase;
use IlluminateFoundationTestingWithoutMiddleware;
use IlluminateFoundationTestingDatabaseMigrations;
use IlluminateFoundationTestingDatabaseTransactions;

class ApiTest extends TestCase
{
    public function testBasicTest()
    {
        $response = $this->get('/');

        $response->assertStatus(200);
    }
}

我用命令运行所有测试

./vendor/bin/phpunit

但结果是：

PHPUnit 5.7.13 by Sebastian Bergmann and contributors.

F                                                                   1 / 1 (100%)

Time: 222 ms,Memory: 12.25MB

There was 1 failure:

1) TestsFeatureApiTest::testBasicTest
Expected status code 200 but received 404.
Failed asserting that false is true.

/Applications/MAMP/htdocs/streaming_statistic/vendor/laravel/framework/src/Illuminate/Foundation/Testing/TestResponse.php:56
/Applications/MAMP/htdocs/streaming_statistic/tests/Feature/ApiTest.php:16

FAILURES!
Tests: 1,Assertions: 1,Failures: 1.

我可以打开这个页面http://localhost:8888/streaming_statistic/public/
我有一条路线：

Route::get('/',function () {
    return view('welcome');
});

我做错了什么？
在laravel中为控制器方法编写测试的正确方法是什么？可能是HTTP测试它不是最好的解决方案吗？