diff --git a/doc/topics/testing.rst b/doc/topics/testing.rst
index ca767490ed..2f0a59b428 100644
--- a/doc/topics/testing.rst
+++ b/doc/topics/testing.rst
@@ -41,7 +41,7 @@ To use it in your own module you just have to inherit from
         @with_transaction()
         def test_method(self):
             "Test method"
-            self.assert_(True)
+            self.assertTrue(True)
 
 
 Tests from this modules are found by the function
diff --git a/trytond/tests/test_field_date.py b/trytond/tests/test_field_date.py
index ffd4f17b41..6bd3007a6d 100644
--- a/trytond/tests/test_field_date.py
+++ b/trytond/tests/test_field_date.py
@@ -82,7 +82,7 @@ class FieldDateTestCase(unittest.TestCase):
 
         date, = Date.create([{'date': CurrentDate()}])
 
-        self.assert_(date.date)
+        self.assertTrue(date.date)
 
     @with_transaction()
     def test_create_non_date(self):
diff --git a/trytond/tests/test_field_datetime.py b/trytond/tests/test_field_datetime.py
index 335499d151..6d402b7b03 100644
--- a/trytond/tests/test_field_datetime.py
+++ b/trytond/tests/test_field_datetime.py
@@ -85,7 +85,7 @@ class FieldDateTimeTestCase(unittest.TestCase):
                     'datetime': DateTime.datetime.sql_cast(CurrentTimestamp()),
                     }])
 
-        self.assert_(datetime.datetime)
+        self.assertTrue(datetime.datetime)
 
     @with_transaction()
     def test_create_non_datetime(self):
diff --git a/trytond/tests/test_field_time.py b/trytond/tests/test_field_time.py
index c838de1cb9..f2303ee048 100644
--- a/trytond/tests/test_field_time.py
+++ b/trytond/tests/test_field_time.py
@@ -83,7 +83,7 @@ class FieldTimeTestCase(unittest.TestCase):
 
         time, = Time.create([{'time': Time.time.sql_cast(CurrentTimestamp())}])
 
-        self.assert_(time.time)
+        self.assertTrue(time.time)
 
     @with_transaction()
     def test_create_non_time(self):