diff --git a/tests/test_account_invoice.py b/tests/test_account_invoice.py
index 6fdfcbdc91..05c5b5716e 100644
--- a/tests/test_account_invoice.py
+++ b/tests/test_account_invoice.py
@@ -15,9 +15,8 @@ import datetime
 from decimal import Decimal
 import trytond.tests.test_tryton
 from trytond.tests.test_tryton import POOL, DB_NAME, USER, CONTEXT, test_view,\
-        test_depends
+    test_depends, doctest_dropdb
 from trytond.transaction import Transaction
-from trytond.backend.sqlite.database import Database as SQLiteDatabase
 
 
 class AccountInvoiceTestCase(unittest.TestCase):
@@ -93,16 +92,6 @@ class AccountInvoiceTestCase(unittest.TestCase):
                     ])
 
 
-def doctest_dropdb(test):
-    database = SQLiteDatabase().connect()
-    cursor = database.cursor(autocommit=True)
-    try:
-        database.drop(cursor, ':memory:')
-        cursor.commit()
-    finally:
-        cursor.close()
-
-
 def suite():
     suite = trytond.tests.test_tryton.suite()
     suite.addTests(unittest.TestLoader().loadTestsFromTestCase(