Quick demonstration of using `DatabaseTransactions` trait in Laravel unit tests

SomeTest.php

<?php

namespace Tests\Feature;

use Illuminate\Foundation\Testing\DatabaseTransactions;
use Tests\TestCase;

class SomeTest extends TestCase
{
    use DatabaseTransactions;

    // uncomment these if you want to use them, and mind the `: void` return type;
    // in Laravel 5.7+, return type of void is mandatory (to enforce invariance~ of void)

    /* public function setUp() : void
    {
        parent::setUp();

        // maybe something here
    }*/

    /* public function tearDown() : void
    {
        parent::tearDown();

        // maybe something here
    }*/

    /** @test */
    public function it_should_rename_someone_to_shirley()
    {
        // do anything, such as:
        $user = User::query()->firstWhere('email', 'shirley@asample.com');
        $user->name = 'Shirley Mutated';
        $user->save();
      
        $this->assertDatabaseHas('users', [
            'email' => 'shirley@asample.com',
            'name' => 'Shirley Mutated',
        ]);
      
        // as the unit test completes, the transaction will be rolled back, w0w!!1!
    }
  
    /** @test */
    public function it_should_still_be_named_shirley()
    {
        // rely on unmutated data in the next test, such as:
        $user = User::query()->firstWhere('email', 'shirley@asample.com');
      
        $this->assertDatabaseHas('users', [
            'email' => 'shirley@asample.com',
            'name' => 'Shirley Immutable',
        ]);
    }
}

This file exists alongside this other required setup file: https://gist.github.com/agm1984/38d893e801ff257cc5da567a42e29fee