diff --git a/src/Runner/Runner.php b/src/Runner/Runner.php
index 25a23ac..32b240a 100644
--- a/src/Runner/Runner.php
+++ b/src/Runner/Runner.php
@@ -225,7 +225,10 @@ public function setConfig($config)
         }
 
         foreach ($config as $key => $val) {
-            $methodName = 'set' . implode(array_map(static fn($value): string => ucfirst($value), explode('_', $key)));
+            $methodName = 'set' . implode(
+                '',
+                array_map(static fn($value): string => ucfirst($value), explode('_', $key))
+            );
 
             if (! is_callable([$this, $methodName])) {
                 throw new BadMethodCallException('Unknown config parameter ' . $key);
@@ -411,7 +414,7 @@ protected function triggerReporters($eventType)
 
     protected function startErrorHandler()
     {
-        set_error_handler([$this, 'errorHandler'], $this->catchErrorSeverity);
+        set_error_handler($this->errorHandler(...), $this->catchErrorSeverity);
     }
 
     /**