Generate PHPStan Rule Test

Create a test class and fixture file for a PHPStan rule in this project.

Steps

1. •Read the rule class source to understand what it checks
2. •Determine the appropriate test directory based on the rule's namespace:
   • •Rules\Classes\ -> tests/src/Rules/
   • •Rules\Deprecations\ -> tests/src/Rules/
   • •Rules\Drupal\ -> tests/src/Rules/
   • •Rules\Drush\ -> tests/src/Rules/
   • •Type\ -> tests/src/Type/
3. •Create the test class following these conventions:
   • •Extend mglaman\PHPStanDrupal\Tests\DrupalRuleTestCase
   • •Use declare(strict_types=1) at the top
   • •Mark the class as final
   • •Implement getRule() returning an instance of the rule
   • •Use @dataProvider cases with a generator
   • •Each case yields [files, errors] where errors are [message, line, tip?]
4. •Create fixture PHP file(s) in tests/src/Rules/data/ or tests/src/Type/data/
5. •Run the test with php vendor/bin/phpunit --filter=TheNewTestClass to verify

Example test structure

<?php

declare(strict_types=1);

namespace mglaman\PHPStanDrupal\Tests\Rules;

use mglaman\PHPStanDrupal\Rules\Drupal\ExampleRule;
use mglaman\PHPStanDrupal\Tests\DrupalRuleTestCase;

final class ExampleRuleTest extends DrupalRuleTestCase
{
    protected function getRule(): \PHPStan\Rules\Rule
    {
        return new ExampleRule();
    }

    /**
     * @dataProvider cases
     *
     * @param list<array{0: string, 1: int, 2?: string|null}> $errors
     */
    public function test(array $files, array $errors): void
    {
        $this->analyse($files, $errors);
    }

    public static function cases(): \Generator
    {
        yield 'passing case' => [
            [__DIR__ . '/data/example-pass.php'],
            [],
        ];
        yield 'failing case' => [
            [__DIR__ . '/data/example-fail.php'],
            [
                ['Error message here.', 10],
            ],
        ];
    }
}