How to seed database migrations for laravel tests?

It took me some digging to figure this out, so I thought I'd share.

If you look at the source code for the DatabaseMigrations trait, then you'll see it has one function runDatabaseMigrations that's invoked by setUp which runs before every test and registers a callback to be run on teardown.

You can sort of "extend" the trait by aliasing that function, re-declare a new function with your logic in it (artisan db:seed) under the original name, and call the alias inside it.

use Illuminate\Foundation\Testing\DatabaseMigrations;

class ExampleTest extends TestCase
{
    use DatabaseMigrations {
        runDatabaseMigrations as baseRunDatabaseMigrations;
    }

    /**
     * Define hooks to migrate the database before and after each test.
     *
     * @return void
     */
    public function runDatabaseMigrations()
    {
        $this->baseRunDatabaseMigrations();
        $this->artisan('db:seed');
    }

    /**
     * A basic functional test example.
     *
     * @return void
     */
    public function testBasicExample()
    {
        $response = $this->get('/');

        // ...
    }
}

All you need to do is make an artisan call db:seed in the setUp function

<?php

use Illuminate\Foundation\Testing\DatabaseMigrations;

class ExampleTest extends TestCase
{
    use DatabaseMigrations;

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

        // seed the database
        $this->artisan('db:seed');
        // alternatively you can call
        // $this->seed();
    }

    /**
     * A basic functional test example.
     *
     * @return void
     */
    public function testBasicExample()
    {
        $response = $this->get('/');

        // ...
    }
}

ref: https://laravel.com/docs/5.6/testing#creating-and-running-tests

With Laravel 8, if you're using the RefreshDatabase trait you can invoke seeding from your test case using below:

use Illuminate\Foundation\Testing\RefreshDatabase;

class ExampleTest extends TestCase
{
    use RefreshDatabase;

    /**
     * A basic functional test example.
     *
     * @return void
     */
    public function testBasicExample()
    {
        // Run the DatabaseSeeder...
        $this->seed();

        // Run a specific seeder...
        $this->seed(OrderStatusSeeder::class);

        $response = $this->get('/');

        // ...
    }
}

see docs for more information/examples: https://laravel.com/docs/8.x/database-testing#running-seeders