Add document statistics test

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

mayan/apps/documents/tests/test_statistics.py

@@ -0,0 +1,18 @@
+from __future__ import unicode_literals
+
+from mayan.apps.common.tests import BaseTestCase
+
+from ..statistics import namespace
+
+
+class DocumentStatisticsTestCase(BaseTestCase):
+    def test_namespace(self):
+        for statistic in namespace.statistics:
+            try:
+                statistic.execute()
+            except Exception as exception:
+                self.fail(
+                    'Error executing: {};  {}'.format(statistic, exception)
+                )
+                raise
+