Add test for the setting environment support.

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

mayan/apps/smart_settings/tests/test_classes.py

@@ -0,0 +1,16 @@
+from __future__ import absolute_import, unicode_literals
+
+import os
+
+from common.settings import setting_paginate_by
+from common.tests import BaseTestCase
+
+from .literals import ENVIRONMENT_TEST_NAME, ENVIRONMENT_TEST_VALUE
+
+
+class ClassesTestCase(BaseTestCase):
+    def test_environment_variable(self):
+        os.environ[
+            'MAYAN_{}'.format(ENVIRONMENT_TEST_NAME)
+        ] = ENVIRONMENT_TEST_VALUE
+        self.assertTrue(setting_paginate_by.value, ENVIRONMENT_TEST_VALUE)