Add a test to test all rules are registered

Inspired by https://x.com/janedbal/status/1920102533520929185

Author: spaze

tests/AllRulesRegisteredTest.php

@@ -0,0 +1,43 @@
+<?php
+declare(strict_types = 1);
+
+namespace Spaze\PHPStan\Rules\Disallowed;
+
+use DirectoryIterator;
+use PHPStan\Testing\PHPStanTestCase;
+
+class AllRulesRegisteredTest extends PHPStanTestCase
+{
+
+	private const RULES_DIRS = [
+		'Calls',
+		'Usages',
+		'HelperRules',
+	];
+
+
+	public function testAllRulesRegistered(): void
+	{
+		foreach (self::RULES_DIRS as $directory) {
+			foreach (new DirectoryIterator(__DIR__ . '/../src/' . $directory) as $file) {
+				if ($file->getExtension() === 'php') {
+					$class = sprintf('Spaze\PHPStan\Rules\Disallowed\%s\%s', $directory, $file->getBasename('.php'));
+					if (!class_exists($class)) {
+						continue;
+					}
+					$services = self::getContainer()->findServiceNamesByType($class);
+					self::assertNotEmpty($services, "{$class} is not a registered rule");
+				}
+			}
+		}
+	}
+
+
+	public static function getAdditionalConfigFiles(): array
+	{
+		return [
+			__DIR__ . '/../extension.neon',
+		];
+	}
+
+}