diff --git a/.php_cs b/.php_cs
index f6b713a..1c408b6 100644
--- a/.php_cs
+++ b/.php_cs
@@ -325,5 +325,6 @@ return PhpCsFixer\Config::create()
         ->exclude('vendor')
         ->in(__DIR__)
         ->name('.php_cs')
+        ->append(glob(__DIR__ . '/scripts/tests/*'))
     )
 ;
diff --git a/scripts/check-installed-extension.php b/scripts/check-installed-extension.php
index 96e3444..9af280c 100644
--- a/scripts/check-installed-extension.php
+++ b/scripts/check-installed-extension.php
@@ -9,7 +9,10 @@ $nameMap = [
 $testsDir = __DIR__ . '/tests';
 function runTest($testFile)
 {
-    return include $testFile;
+    $rc = -1;
+    passthru($testFile, $rc);
+
+    return $rc === 0;
 }
 
 for ($index = 1, $count = isset($argv) ? count($argv) : 0; $index < $count; $index++) {
@@ -26,7 +29,7 @@ for ($index = 1, $count = isset($argv) ? count($argv) : 0; $index < $count; $ind
         if (!extension_loaded($extension)) {
             fprintf(STDERR, sprintf("Extension not loaded: %s\n", $extension));
         } else {
-            $testFile = "{$testsDir}/{$extension}.php";
+            $testFile = "{$testsDir}/{$extension}";
             if (is_file($testFile)) {
                 try {
                     if (runTest($testFile) === true) {
diff --git a/scripts/tests/gd.php b/scripts/tests/gd
old mode 100644
new mode 100755
similarity index 71%
rename from scripts/tests/gd.php
rename to scripts/tests/gd
index e9406a0..16d2d54
--- a/scripts/tests/gd.php
+++ b/scripts/tests/gd
@@ -1,5 +1,21 @@
+#!/usr/bin/env php
 <?php
 
+set_error_handler(
+    static function ($errno, $errstr, $errfile, $errline) {
+        $msg = "Error {$errno}: {$errstr}\n";
+        if ($errfile) {
+            $msg .= "File: {$errfile}\n";
+            if ($errline) {
+                $msg .= "Line: {$errline}\n";
+            }
+        }
+        fwrite(STDERR, $msg);
+        exit(1);
+    },
+    -1
+);
+
 $imageWidth = 8;
 $imageHeight = 16;
 $image = imagecreatetruecolor($imageWidth, $imageHeight);
@@ -60,6 +76,19 @@ try {
         }
         imagedestroy($image2);
     }
+    if (!function_exists('imagefttext')) {
+        throw new Exception('imagefttext() function is missing');
+    }
+    if (!function_exists('imageantialias')) {
+        throw new Exception('imageantialias() function is missing');
+    }
+    $rc = 0;
+} catch (Exception $x) {
+    $rc = 1;
+    fwrite(STDERR, $x->getMessage());
+} catch (Throwable $x) {
+    $rc = 1;
+    fwrite(STDERR, $x->getMessage());
 } finally {
     imagedestroy($image);
     if (is_resource($image2)) {
@@ -69,12 +98,4 @@ try {
         unlink($tempFile);
     }
 }
-
-if (!function_exists('imagefttext')) {
-    throw new Exception('imagefttext() function is missing');
-}
-if (!function_exists('imageantialias')) {
-    throw new Exception('imageantialias() function is missing');
-}
-
-return true;
+exit($rc);