diff --git a/muk_web_preview_attachment/tests/test_attachment_extension.py b/muk_web_preview_attachment/tests/test_attachment_extension.py
index 5c7f57e..3c05acd 100644
--- a/muk_web_preview_attachment/tests/test_attachment_extension.py
+++ b/muk_web_preview_attachment/tests/test_attachment_extension.py
@@ -42,7 +42,7 @@ class AttachmentExtensionTestCase(common.TransactionCase):
     def tearDown(self):
         super(AttachmentExtensionTestCase, self).tearDown()
         
-    def test_attachment_extension(self):
+    def test_attachment_extension_filename(self):
         with closing(open(os.path.join(_path, 'tests/data/sample.png'), 'r')) as file:
             self.sample = self.attachment_model.create({
                 'name': "test",
@@ -51,6 +51,14 @@ class AttachmentExtensionTestCase(common.TransactionCase):
             })
         self.assertEqual(self.sample.extension, ".png")
         
+    def test_attachment_extension_bianry(self):
+        with closing(open(os.path.join(_path, 'tests/data/sample.png'), 'r')) as file:
+            self.sample = self.attachment_model.create({
+                'name': "test",
+                'datas': base64.encodestring(file.read()),
+            })
+        self.assertEqual(self.sample.extension, ".png")
+        
         
     
         
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