diff --git a/tests/src/FilesystemTest.php b/tests/src/FilesystemTest.php
index 89b4d26..da30e76 100644
--- a/tests/src/FilesystemTest.php
+++ b/tests/src/FilesystemTest.php
@@ -177,7 +177,7 @@ public function testWriteStream()
         $mockAdapter = $this->createMock(FilesystemAdapter::class);
         $mockAdapter->expects($this->once())->method('writeStream')->with(
             $this->equalTo('test'),
-            $this->callback(function($value) {
+            $this->callback(function ($value) {
                 return \is_resource($value);
             }),
             $this->anything()