feat(docs): enhance DocumentationMenuItem validation and file checks

src/Documentation/DocumentationMenuItem.php

@@ -10,14 +10,20 @@
 final readonly class DocumentationMenuItem
 {
     /**
-     * @param non-empty-string|null $slug
+     * @param string $href The URL path for the documentation menu item. Must be a non-empty string starting with '/'
+     * @param string $label The display text for the menu item. Must be a non-empty string
+     * @param non-empty-string|null $slug The unique identifier for the documentation file. If null, indicates a menu item without content
+     * @param bool $isNew Whether this menu item represents new documentation
      */
     public function __construct(
         private string $href,
         private string $label,
         private ?string $slug,
         private bool $isNew = false,
     ) {
+        Assert::notEmpty($href, 'Documentation href cannot be empty');
+        Assert::startsWith($href, '/', 'Documentation href must start with a forward slash');
+        Assert::notEmpty($label, 'Documentation label cannot be empty');
     }
 
     public function getHref(): string
@@ -43,12 +49,37 @@ public function getSlug(): ?string
         return $this->slug;
     }
 
+    /**
+     * Checks if the documentation file exists for this menu item.
+     * 
+     * @return bool True if the documentation file exists and is readable, false otherwise
+     */
+    public function hasDocumentation(): bool
+    {
+        if ($this->slug === null) {
+            return false;
+        }
+
+        $documentationFilePath = $this->getDocumentationFilePath();
+        return file_exists($documentationFilePath) && is_readable($documentationFilePath);
+    }
+
     public function getMarkdownContents(): string
     {
         Assert::notNull($this->slug);
-        $documentationFilePath = __DIR__ . '/../../resources/docs/' . $this->slug . '.md';
+        $documentationFilePath = $this->getDocumentationFilePath();
 
         Assert::fileExists($documentationFilePath);
         return FileSystem::read($documentationFilePath);
     }
+
+    /**
+     * Gets the full path to the documentation file.
+     * 
+     * @return string The absolute path to the documentation file
+     */
+    private function getDocumentationFilePath(): string
+    {
+        return __DIR__ . '/../../resources/docs/' . $this->slug . '.md';
+    }
 }

src/ValueObject/AppliedRule.php

@@ -6,9 +6,15 @@
 
 use App\Exception\ShouldNotHappenException;
 use Nette\Utils\Strings;
+use Webmozart\Assert\Assert;
 
 final readonly class AppliedRule
 {
+    private const EXPECTED_CLASS_PARTS_COUNT = 5;
+    private const CATEGORY_INDEX = 1;
+    private const NODE_CLASS_INDEX = 3;
+    private const SHORT_CLASS_INDEX = 4;
+
     private string $shortRectorClass;
 
     public function __construct(
@@ -40,16 +46,48 @@ public function getTestFixtureNamespace(): string
     public function getTestFixtureDirectoryPath(): string
     {
         $classParts = explode('\\', $this->rectorClass);
+
+        // Validate class structure
+        Assert::count(
+            $classParts,
+            self::EXPECTED_CLASS_PARTS_COUNT,
+            sprintf(
+                'Rector class "%s" must have exactly %d parts (e.g. "Rector\\Category\\Node\\SomeRector")',
+                $this->rectorClass,
+                self::EXPECTED_CLASS_PARTS_COUNT
+            )
+        );
 
-        $category = $classParts[1];
-        $rulesDirectory = 'rules-tests/' . $category;
+        // Validate and get required parts
+        $category = $this->getClassPart($classParts, self::CATEGORY_INDEX, 'category');
+        $nodeClass = $this->getClassPart($classParts, self::NODE_CLASS_INDEX, 'node class');
+        $shortClass = $this->getClassPart($classParts, self::SHORT_CLASS_INDEX, 'short class');
 
-        $nodeClass = $classParts[3];
-        $shortClass = $classParts[4];
+        $rulesDirectory = 'rules-tests/' . $category;
 
         return $rulesDirectory . '/Rector/' . $nodeClass . '/' . $shortClass . '/Fixture';
     }
 
+    /**
+     * @param string[] $classParts
+     */
+    private function getClassPart(array $classParts, int $index, string $partName): string
+    {
+        Assert::keyExists(
+            $classParts,
+            $index,
+            sprintf('Missing %s in rector class "%s"', $partName, $this->rectorClass)
+        );
+
+        $part = $classParts[$index];
+        Assert::notEmpty(
+            $part,
+            sprintf('Empty %s in rector class "%s"', $partName, $this->rectorClass)
+        );
+
+        return $part;
+    }
+
     /**
      * Mimics @see \App\RuleFilter\ValueObject\RuleMetadata::getSlug()
      */