diff --git a/tests/test_file_storage.py b/tests/test_file_storage.py
index decacd81..b1cdfb88 100644
--- a/tests/test_file_storage.py
+++ b/tests/test_file_storage.py
@@ -1,9 +1,53 @@
 import os
 import tempfile
 
+from werkzeug.datastructures import FileStorage
+
 from common_test_class import AbstractPillarTest
 
 
+class FileStorageTest(AbstractPillarTest):
+    def fake_file(self, filename, content_type):
+        return FileStorage(filename=filename,
+                           name='file',  # form field name
+                           content_type=content_type)
+
+    def test_override_content_type(self):
+        from application.modules.file_storage import override_content_type
+
+        fake = self.fake_file('compressed.blend', 'jemoeder')
+        override_content_type(fake)
+        self.assertEqual('application/x-blend', fake.content_type)
+        self.assertEqual('application/x-blend', fake.mimetype)
+
+        fake = self.fake_file('blend.mp3', 'application/octet-stream')
+        override_content_type(fake)
+        self.assertEqual('audio/mpeg', fake.content_type)
+        self.assertEqual('audio/mpeg', fake.mimetype)
+
+        # Official one is audio/mpeg, but if the browser gives audio/XXX, it should
+        # just be used.
+        fake = self.fake_file('blend.mp3', 'audio/mp3')
+        override_content_type(fake)
+        self.assertEqual('audio/mp3', fake.content_type)
+        self.assertEqual('audio/mp3', fake.mimetype)
+
+        fake = self.fake_file('mp3.mkv', 'application/octet-stream')
+        override_content_type(fake)
+        self.assertEqual('video/x-matroska', fake.content_type)
+        self.assertEqual('video/x-matroska', fake.mimetype)
+
+        fake = self.fake_file('mkv.mp3.avi.mp4', 'application/octet-stream')
+        override_content_type(fake)
+        self.assertEqual('video/mp4', fake.content_type)
+        self.assertEqual('video/mp4', fake.mimetype)
+
+        fake = self.fake_file('mkv.mp3.avi.mp4.unknown', 'application/awesome-type')
+        override_content_type(fake)
+        self.assertEqual('application/awesome-type', fake.content_type)
+        self.assertEqual('application/awesome-type', fake.mimetype)
+
+
 class TempDirTest(AbstractPillarTest):
     def test_tempfiles_location(self):
         # After importing the application, tempfiles should be created in the STORAGE_DIR