Don't pass null to strlen()

diff --git a/run-tests.php b/run-tests.php
index d0eaa2b638726be2786eaac6c4e3f7de40dcd500..5cb376cba29a7ddc335b6a96cc7f8c64a6046214 100755 (executable)
--- a/run-tests.php
+++ b/run-tests.php
@@ -699,7 +699,7 @@ function main(): void
         $environment['TEST_PHP_EXECUTABLE'] = $php;
     }
 
-    if (strlen($conf_passed)) {
+    if ($conf_passed !== null) {
         if (IS_WINDOWS) {
             $pass_options .= " -c " . escapeshellarg($conf_passed);
         } else {