diff --git a/tests/RequestBuilderTest.php b/tests/RequestBuilderTest.php
index e5be740..b1f332a 100644
--- a/tests/RequestBuilderTest.php
+++ b/tests/RequestBuilderTest.php
@@ -40,6 +40,6 @@ class RequestBuilderTest extends \PHPUnit_Framework_TestCase
         $this->assertContains('username', $body);
         $this->assertContains('Stockholm', $body);
         $this->assertContains('city', $body);
-        $this->assertRegExp('|^multipart/form-data; boundary=[0-9a-z]+$|si', $contentType);
+        $this->assertRegExp('|^multipart/form-data; boundary=(?P<quote>"?)[\w\Q\'()+,-./:=?\E]{1,69}(?P=quote)$|si', $contentType);
     }
 }