Add test for internal error when calling undefined functions (#273)

Follow up to #272

Author: IanDelMar

tests/HookCallbackRuleTest.php

@@ -54,6 +54,7 @@ public function testRule(): void
         $this->analyse(
             [
                 __DIR__ . '/data/hook-callback.php',
+                __DIR__ . '/data/internal-error.php',
             ],
             self::EXPECTED_ERRORS
         );

tests/HookDocsRuleTest.php

@@ -31,6 +31,7 @@ public function testRule(): void
         $this->analyse(
             [
                 __DIR__ . '/data/hook-docs.php',
+                __DIR__ . '/data/internal-error.php',
             ],
             [
                 [

tests/data/internal-error.php

@@ -0,0 +1,7 @@
+<?php
+
+/*
+ * Intentionally call an undefined function to ensure it does not trigger an internal error.
+ * Related issue: https://github.com/szepeviktor/phpstan-wordpress/issues/271
+ */
+callingUndefinedFunction();