AddDoesNotPerformAssertionToNonAssertingTestRector

Tests without assertion will have @doesNotPerformAssertion

 use PHPUnit\Framework\TestCase;

 class SomeClass extends TestCase
 {
+    /**
+     * @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,
    ]);