diff --git a/.drone.yml b/.drone.yml
index e0bc2f7..9f91ecb 100644
--- a/.drone.yml
+++ b/.drone.yml
@@ -13,8 +13,6 @@ pipeline:
         commands:
             - pip install tox
             - tox -e "${TOXENV}-${DATABASE}"
-        volumes:
-            - cache:/root/.cache
 
 services:
     postgresql:
diff --git a/setup.py b/setup.py
index ad46689..3e8ab8b 100644
--- a/setup.py
+++ b/setup.py
@@ -117,7 +117,4 @@ setup(name='%s_%s' % (PREFIX, MODULE),
     test_loader='trytond.test_loader:Loader',
     tests_require=tests_require,
     use_2to3=True,
-    convert_2to3_doctests=[
-        'tests/scenario_country_zip.rst',
-        ],
     )
diff --git a/tests/__init__.py b/tests/__init__.py
index 6d95752..1d903d8 100644
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -1,7 +1,9 @@
-#This file is part helloword module for Tryton.
-#The COPYRIGHT file at the top level of this repository contains 
-#the full copyright notices and license terms.
-
-from .test_country_zip import suite
+# This file is part helloword module for Tryton.  The COPYRIGHT file at the top
+# level of this repository contains the full copyright notices and license
+# terms.
+try:
+    from trytond.modules.country_zip.tests.test_country_zip import suite
+except ImportError:
+    from .test_country_zip import suite
 
 __all__ = ['suite']
diff --git a/tox.ini b/tox.ini
index 527d859..3d844ea 100644
--- a/tox.ini
+++ b/tox.ini
@@ -15,4 +15,4 @@ setenv =
     sqlite: DB_NAME={env:SQLITE_NAME::memory:}
     postgresql: DB_NAME={env:POSTGRESQL_NAME:test}
     mysql: DB_NAME={env:MYSQL_NAME:test}
-install_command = pip install --pre --find-links https://trydevpi.tryton.org/ {opts} {packages}
+install_command = pip install --pre --process-dependency-links {opts} {packages}