Fix failing test of factory if there is no psycopg

This is required for simplifying the test suite

tests/test_factory.py

@@ -25,11 +25,14 @@ import sys
 from pwman.data import factory
 from pwman.data.database import DatabaseException
 from pwman.data.drivers.sqlite import SQLite
-from pwman.data.drivers.postgresql import PostgresqlDatabase
 from pwman.data.database import __DB_FORMAT__
 from .test_tools import (SetupTester)
-
-db =  ".".join(("pwman","test", sys.version.split(" " ,1)[0], "db"))
+try:
+    from pwman.data.drivers.postgresql import PostgresqlDatabase
+    has_psycopg = True
+except ImportError:
+    has_psycopg = False
+db = ".".join(("pwman", "test", sys.version.split(" ", 1)[0], "db"))
 testdb = os.path.abspath(os.path.join(os.path.dirname(__file__), db))
 
 _saveconfig = False
@@ -49,7 +52,8 @@ class TestFactory(unittest.TestCase):
         self.tester.create()
 
     def test_factory_check_db_ver(self):
-        self.assertEqual(factory.check_db_version('sqlite://'+testdb), u"'0.6'")
+        self.assertEqual(
+            factory.check_db_version('sqlite://'+testdb), u"'0.6'")
 
     @unittest.skip("not supported at the moment")
     def test_factory_check_db_file(self):
@@ -67,21 +71,26 @@ class TestFactory(unittest.TestCase):
         db.close()
         os.unlink(fn)
         self.assertIsInstance(db, SQLite)
-        self.assertRaises(DatabaseException, factory.createdb, *('UNKNOWN',
-                                                                 __DB_FORMAT__))
+        self.assertRaises(DatabaseException, factory.createdb,
+                          *('UNKNOWN', __DB_FORMAT__))
 
     def test_factory_createdb(self):
         db = factory.createdb("sqlite:///test.db", 0.6)
         self.assertIsInstance(db, SQLite)
         del db
-        db = factory.createdb("postgresql:///pwman", 0.6)
-        self.assertIsInstance(db, PostgresqlDatabase)
-        del db
         db = factory.createdb("sqlite:///test.db", 0.7)
         self.assertIsInstance(db, SQLite)
         del db
+
+    @unittest.skipUnless(has_psycopg, "requires psycopg")
+    def test_factory_createdb_postgresql(self):
+        db = factory.createdb("postgresql:///pwman", 0.6)
+        self.assertIsInstance(db, PostgresqlDatabase)
+        del db
         db = factory.createdb("postgresql:///pwman", 0.7)
         self.assertIsInstance(db, PostgresqlDatabase)
+        del db
+
 
 if __name__ == '__main__':
     # make sure we use local pwman