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Make RefreshDatabase trait much faster

Published 26 June, 2021

Laravel provides the Illuminate\Foundation\Testing\RefreshDatabase trait to reset the database after each test so that data from a previous test does not interfere with subsequent tests.

The RefreshDatabase trait uses the artisan command migrate:fresh to drop all the tables from the database and then execute the migrate command; this is useful when you create or modify migrations.

In large applications with hundreds of migrations, the migrate:fresh could potentially slow down your tests.

This post will show you an easy solution to make your tests run faster by only executing the migrate:fresh when necessary.

RefreshTestDatabase Trait

The refreshTestDatabase method in RefreshDatabase trait is responsible for migrating the database using the artisan command migrate:fresh, which drops all the tables and migrate:

protected function refreshTestDatabase()
{
    if (! RefreshDatabaseState::$migrated) {
        $this->artisan('migrate:fresh');

        $this->app[Kernel::class]->setArtisan(null);

        RefreshDatabaseState::$migrated = true;
        }

    $this->beginDatabaseTransaction();
}

Read more about migrate:fresh

The code is pretty straightforward, first of all, it checks for the migrations state, then it runs the migrate:fresh if necessary. Checking the state avoids running the migrate:fresh on each test, which is an expensive operation.

The issue with migrate:fresh command

Let me raise a flag here; the migrate:fresh will be executed whenever we run phpunit:

# drop and migrate the database #1
./vendor/bin/phpunit

# drop and migrate the database #2
./vendor/bin/phpunit --filter="my_test"

# drop and migrate the database #3
./vendor/bin/phpunit --filter="my_test2"

Dropping/migrating the database makes sense if you make some changes by creating or modifying migrations, but what if you don’t do that?

Let’s have a look at the following example.

You create a new languages migration:

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

return new class extends Migration
{
    public function up()
    {
        Schema::create('languages', function (Blueprint $table) {
            $table->id();
            $table->string('code', 2)->unique();
            $table->string('name')->unique();
            $table->string('native_name')->unique();
            $table->timestamps();
        });
    }
};

Then you write some tests:

use Tests\TestCase;

class LanguageTest extends TestCase
{
    /** @test **/
    public function it_creates_langage()
    {
        // ...
    }

    /** @test **/
    public function it_updates_langage()
    {
        // ...
    }   

    /** @test **/
    public function it_deletes_langage()
    {
        // ...
    }   
}

And you run the test:

# running the test for the 1st time

./vendor/bin/phpunit --filter="it_creates_a_new_langage"

You might need to run the test several times, because you’re working on some improvements:

# running the test for the 2nd time
./vendor/bin/phpunit --filter="it_creates_a_new_langage"

That is the problem! Laravel should not drop and migrate the database unless we make some changes to the migrations.

For example, renaming the code column to iso_639_1 should force Laravel to drop and migrate the database:

$table->string('iso_639_1', 2)->unique();

In short, we don’t need the migrate:fresh to be executed whenever we run phpunit, that’s it.

Make it faster

We can easily avoid the migrate:fresh command on each phpunit execution unless we make some changes in the migrations.

Let’s see how it works.

  1. First of all, we need to calculate and save the checksum of the entire migrations folder; we can use Symfony Finder by iterating over the database/migrations folder and calculate the checksum for each migration file using the md5_file function.
  2. Then we compare the checksum on the next test run; if the current checksum is different than the saved one, then we run the migrate:fresh otherwise, we skip it.

That’s it, let’s get started.

Implementation

Create a new trait named RefreshTestDatabase in /tests folder.

namespace Tests;

use Illuminate\Contracts\Console\Kernel;
use Illuminate\Foundation\Testing\DatabaseTransactions;
use Illuminate\Foundation\Testing\RefreshDatabaseState;
use Symfony\Component\Finder\Finder;

trait RefreshTestDatabase
{
    use DatabaseTransactions;

    protected function refreshTestDatabase(): void
    {
        if (! RefreshDatabaseState::$migrated) {
            $this->runMigrationsIfNecessary();

            $this->app[Kernel::class]->setArtisan(null);

            RefreshDatabaseState::$migrated = true;
        }

        $this->beginDatabaseTransaction();
    }

    protected function runMigrationsIfNecessary(): void
    {
        if (false === $this->identicalChecksum()) {
            $this->createChecksum();
            $this->artisan('migrate:fresh');
        }
    }

    protected function calculateChecksum(): string
    {
        $files = Finder::create()
            ->files()
            ->exclude([
                'factories',
                'seeders',
            ])
            ->in(database_path())
            ->ignoreDotFiles(true)
            ->ignoreVCS(true)
            ->getIterator();

        $files = array_keys(iterator_to_array($files));

        $checksum = collect($files)->map(fn($file) => md5_file($file))->implode('');

        return md5($checksum);
    }

    protected function checksumFilePath(): string
    {
        return base_path('.phpunit.database.checkum');
    }

    protected function createChecksum(): void
    {
        file_put_contents($this->checksumFilePath(), $this->calculateChecksum());
    }

    protected function checksumFileContents(): bool|string
    {
        return file_get_contents($this->checksumFilePath());
    }

    protected function isChecksumExists(): bool
    {
        return file_exists($this->checksumFilePath());
    }

    protected function identicalChecksum(): bool
    {
        if (false === $this->isChecksumExists()) {
            return false;
        }

        if ($this->checksumFileContents() === $this->calculateChecksum()) {
            return true;
        }

        return false;
    }
}

From now and then, you should use the RefreshTestDatabase trait instead of the RefreshDatabase one.

The next step is to call the refreshTestDatabase method whenever you use the trait in your test files, this is done through the setUpTraits method in the Tests\TestCase file:

namespace Tests;

use Illuminate\Foundation\Testing\RefreshDatabase;
use Illuminate\Foundation\Testing\TestCase as BaseTestCase;

abstract class TestCase extends BaseTestCase
{
    use CreatesApplication;
    use RefreshDatabase;

    protected function setUpTraits()
    {
        $uses = parent::setUpTraits();

        if (isset($uses[RefreshTestDatabase::class])) {
            $this->refreshTestDatabase();
        }

        return $uses;
    }
}

The last step is to add the .phpunit.database.checkum entry into the .gitignore file.

Try to run some tests and depends on the amount of your tests, you might notice a huge difference.

Here is the benchmark for one of my projects, which concist of more than 300 migrations:

  • Without checksum: 9.229 s
  • With checksum: 222.2 ms

That’s all.

I hope you enjoyed reading the post.

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