diff --git a/muk_web_preview_attachment/tests/test_attachment_extension.py b/muk_web_preview_attachment/tests/test_attachment_extension.py
index ca7411a..4e944af 100644
--- a/muk_web_preview_attachment/tests/test_attachment_extension.py
+++ b/muk_web_preview_attachment/tests/test_attachment_extension.py
@@ -47,7 +47,7 @@ class AttachmentExtensionTestCase(common.TransactionCase):
             self.sample = self.attachment_model.create({
                 'name': "test",
                 'datas_fname': "sample.png",
-                'datas': base64.encodestring(file.read()),
+                'datas': base64.b64decode(file.read()),
             })
         self.assertEqual(self.sample.extension, ".png")
         
diff --git a/muk_web_preview_mail/tests/test_mail_parse.py b/muk_web_preview_mail/tests/test_mail_parse.py
index e0034ec..cf85873 100644
--- a/muk_web_preview_mail/tests/test_mail_parse.py
+++ b/muk_web_preview_mail/tests/test_mail_parse.py
@@ -44,7 +44,7 @@ class MailParseTestCase(common.TransactionCase):
             self.sample_mail_attachment = self.attachment_model.create({
                 'name': 'SampleMail',
                 'datas_fname': "sample.eml",
-                'datas': base64.encodestring(file.read()),
+                'datas': base64.b64decode(file.read()),
             })
 
     def tearDown(self):