-def test_transform():
-    mobi = WLDocument.from_file(
-            get_fixture('text', 'asnyk_zbior.xml'),
-            provider=DirDocProvider(get_fixture('text', ''))
-        ).as_mobi(converter_path='true').get_file()
+class MobiTests(unittest.TestCase):
+    def test_transform(self):
+        mobi = MobiBuilder().build(
+            WLDocument(
+                get_fixture('text', 'asnyk_zbior.xml'),
+                provider=DirDocProvider(get_fixture('text', ''))
+            )
+        )