diff --git a/pyfamsa/_famsa.pyx b/pyfamsa/_famsa.pyx
index 7e465b6..0e068bd 100644
--- a/pyfamsa/_famsa.pyx
+++ b/pyfamsa/_famsa.pyx
@@ -114,7 +114,6 @@ cdef class Sequence:
             raise ValueError("Cannot create an empty sequence")
         self._cseq = move(CSequence(id, sequence, 0, NULL))
         self._shape[0] = self._cseq.length
-        # assert self._cseq.mma is not NULL
 
     def __copy__(self):
         return self.copy()
diff --git a/pyfamsa/tests/test_sequence.py b/pyfamsa/tests/test_sequence.py
index 00d919b..15720c6 100644
--- a/pyfamsa/tests/test_sequence.py
+++ b/pyfamsa/tests/test_sequence.py
@@ -22,10 +22,6 @@ def test_buffer_export(self):
         b = mem.tobytes()
         self.assertEqual(len(b), 4)
 
-    def test_buffer_export_empty(self):
-        seq = Sequence(b"", b"")
-        mem = memoryview(seq)
-        self.assertEqual(mem.shape[0], 0)
-        self.assertTrue(mem.readonly)
-        b = mem.tobytes()
-        self.assertEqual(len(b), 0)
+    def test_error_empty(self):
+        with self.assertRaises(ValueError):
+            seq = Sequence(b"", b"")