AddDoesNotPerformAssertionToNonAssertingTestRector

Tests without assertion will have #[DoesNotPerformAssertions] attribute, or @doesNotPerformAssertions annotation on PHPUnit below 10

 use PHPUnit\Framework\TestCase;

 class SomeClass extends TestCase
 {
+    #[\PHPUnit\Framework\Attributes\DoesNotPerformAssertions]
     public function test()
     {
         $nothing = 5;
     }
 }

Configure your rector.php:

<?php

use Rector\Config\RectorConfig;
use Rector\PHPUnit\PHPUnit60\Rector\ClassMethod\AddDoesNotPerformAssertionToNonAssertingTestRector;

return RectorConfig::configure()
    ->withRules([
        AddDoesNotPerformAssertionToNonAssertingTestRector::class,
    ]);
PACKAGE:  phpunit/phpunit >=6.0