Postgres tests not failing when postgres not installed. Fixes #78.

AUTHORS

@@ -71,3 +71,4 @@ Thanks To
 * Ruijun Luo, figuring out incorrect openssl import for wrap_ssl (#73)
 * rfk, patch to get green zmq to respect noblock flag.
 * Soren Hansen, finding and fixing issue in subprocess (#77)
+* Stefano Rivera, making tests pass in absence of postgres (#78)

tests/patcher_psycopg_test.py

@@ -1,7 +1,8 @@
 import os
 
-from tests import patcher_test
+from tests import patcher_test, skip_unless
 from tests import get_database_auth
+from tests.db_pool_test import postgres_requirement
 
 psycopg_test_file = """
 import os
@@ -35,6 +36,7 @@ print "done"
 """
 
 class PatchingPsycopg(patcher_test.ProcessBase):
+    @skip_unless(postgres_requirement)
     def test_psycopg_patched(self):
         if 'PSYCOPG_TEST_DSN' not in os.environ:
             # construct a non-json dsn for the subprocess