diff --git a/setup.py b/setup.py
index 6ceb86f0a9..7e514adca1 100755
--- a/setup.py
+++ b/setup.py
@@ -146,13 +146,13 @@ setup(name=name,
     license='GPL-3',
     python_requires='>=3.7',
     install_requires=requires,
+    extras_require={
+        'test': tests_require,
+        },
     dependency_links=dependency_links,
     zip_safe=False,
     entry_points="""
     [trytond.modules]
     account_invoice_watermark = trytond.modules.account_invoice_watermark
     """,  # noqa: E501
-    test_suite='tests',
-    test_loader='trytond.test_loader:Loader',
-    tests_require=tests_require,
     )
diff --git a/tests/__init__.py b/tests/__init__.py
index 23d2b3a44f..4effdfa4a2 100644
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -1,10 +1,2 @@
 # This file is part of Tryton.  The COPYRIGHT file at the top level of
 # this repository contains the full copyright notices and license terms.
-
-try:
-    from trytond.modules.account_invoice_watermark.tests.test_account_invoice_watermark import \
-        suite  # noqa: E501
-except ImportError:
-    from .test_account_invoice_watermark import suite
-
-__all__ = ['suite']
diff --git a/tests/test_account_invoice_watermark.py b/tests/test_account_invoice_watermark.py
deleted file mode 100644
index 74efe40cdf..0000000000
--- a/tests/test_account_invoice_watermark.py
+++ /dev/null
@@ -1,28 +0,0 @@
-# This file is part of Tryton.  The COPYRIGHT file at the top level of
-# this repository contains the full copyright notices and license terms.
-
-import doctest
-import shutil
-import unittest
-
-from trytond.tests.test_tryton import (
-    ModuleTestCase, doctest_checker, doctest_teardown)
-from trytond.tests.test_tryton import suite as test_suite
-
-
-class AccountInvoiceWatermarkTestCase(ModuleTestCase):
-    'Test Account Invoice Watermark module'
-    module = 'account_invoice_watermark'
-
-
-def suite():
-    suite = test_suite()
-    suite.addTests(unittest.TestLoader().loadTestsFromTestCase(
-            AccountInvoiceWatermarkTestCase))
-    if shutil.which('soffice') and shutil.which('mutool'):
-        suite.addTests(doctest.DocFileSuite(
-                'scenario_account_invoice_watermark.rst',
-                tearDown=doctest_teardown, encoding='utf-8',
-                checker=doctest_checker,
-                optionflags=doctest.REPORT_ONLY_FIRST_FAILURE))
-    return suite
diff --git a/tests/test_module.py b/tests/test_module.py
new file mode 100644
index 0000000000..27b469295b
--- /dev/null
+++ b/tests/test_module.py
@@ -0,0 +1,12 @@
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
+
+from trytond.tests.test_tryton import ModuleTestCase
+
+
+class AccountInvoiceWatermarkTestCase(ModuleTestCase):
+    'Test Account Invoice Watermark module'
+    module = 'account_invoice_watermark'
+
+
+del ModuleTestCase
diff --git a/tests/test_scenario.py b/tests/test_scenario.py
new file mode 100644
index 0000000000..14575722c3
--- /dev/null
+++ b/tests/test_scenario.py
@@ -0,0 +1,24 @@
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
+
+import doctest
+import glob
+import os
+import shutil
+
+from trytond.tests.test_tryton import doctest_checker, doctest_teardown
+
+
+def load_tests(loader, tests, pattern):
+    if shutil.which('soffice') and shutil.which('mutool'):
+        cwd = os.getcwd()
+        try:
+            os.chdir(os.path.dirname(__file__))
+            for scenario in glob.glob('*.rst'):
+                tests.addTests(doctest.DocFileSuite(
+                        scenario, tearDown=doctest_teardown, encoding='utf-8',
+                        checker=doctest_checker,
+                        optionflags=doctest.REPORT_ONLY_FIRST_FAILURE))
+        finally:
+            os.chdir(cwd)
+    return tests
diff --git a/tox.ini b/tox.ini
index 1717942bcf..db80811c49 100644
--- a/tox.ini
+++ b/tox.ini
@@ -2,8 +2,9 @@
 envlist = {py37,py38,py39,py310}-{sqlite,postgresql}
 
 [testenv]
+extras = test
 commands =
-    coverage run --include=.*/account_invoice/* setup.py test
+    coverage run --include=.*/account_invoice/* -m unittest discover -s tests
     coverage report --include=.*/account_invoice/* --omit=*/tests/*
 deps =
     coverage