Skip test when not able to detect vendor/autoload.php

Author: kelunik

test/phpt/error_handler_007.phpt

@@ -3,7 +3,10 @@ ErrorHandler::notify() fatals with a throwing error handler
 --SKIPIF--
 <?php
 
-// Warning: This relies on the current working directory in which PHPUnit is executed.
+if (!file_exists(__DIR__ . "/vendor/autoload.php")) {
+    die("Skipped: Cannot detect PHPUnit version, run tests from project root.");
+}
+
 // If the directory is not the root of the project, this will silently fail and execute the test below.
 require __DIR__ . "/vendor/autoload.php";