diff --git a/requirements.txt b/requirements.txt
index 0685cb129..8c23ed63c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,6 +1,3 @@
-# The order of packages is significant, because pip processes them in the order
-# of appearance. Changing the order has an impact on the overall integration
-# process, which may cause wedges in the gate later.
 pbr!=2.1.0,>=2.0.0 # Apache-2.0
 
 alembic>=0.9.6 # MIT
diff --git a/test-requirements.txt b/test-requirements.txt
index 61dfe3b44..b82d4dcca 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -1,8 +1,4 @@
-# The order of packages is significant, because pip processes them in the order
-# of appearance. Changing the order has an impact on the overall integration
-# process, which may cause wedges in the gate later.
-# Metrics and style
-hacking>=3.0.1,<3.1.0 # Apache-2.0
+hacking>=6.1.0,<6.2.0 # Apache-2.0
 
 # Backends
 redis>=3.0.0 # MIT
diff --git a/zaqar/storage/mongodb/utils.py b/zaqar/storage/mongodb/utils.py
index b006756e7..b3626953b 100644
--- a/zaqar/storage/mongodb/utils.py
+++ b/zaqar/storage/mongodb/utils.py
@@ -301,14 +301,14 @@ def retries_on_autoreconnect(func):
                 break
 
             except errors.AutoReconnect as ex:
-                LOG.warning(u'Caught AutoReconnect, retrying the '
-                            'call to {0}'.format(func))
+                LOG.warning('Caught AutoReconnect, retrying the '
+                            'call to %s', func.__name__)
 
                 last_ex = ex
                 time.sleep(sleep_sec * (2 ** attempt))
         else:
-            LOG.error(u'Caught AutoReconnect, maximum attempts '
-                      'to {0} exceeded.'.format(func))
+            LOG.error('Caught AutoReconnect, maximum attempts '
+                      'to %s exceeded.', func.__name__)
 
             raise last_ex
 
diff --git a/zaqar/storage/redis/utils.py b/zaqar/storage/redis/utils.py
index 448c73ab5..705b84903 100644
--- a/zaqar/storage/redis/utils.py
+++ b/zaqar/storage/redis/utils.py
@@ -203,13 +203,13 @@ def retries_on_connection_error(func):
                 # MasterNotFoundError.
 
                 ex = sys.exc_info()[1]
-                LOG.warning(u'Caught ConnectionError, retrying the '
-                            'call to {0}'.format(func))
+                LOG.warning('Caught ConnectionError, retrying the '
+                            'call to %s', func.__name__)
 
                 time.sleep(sleep_sec * (2 ** attempt))
         else:
-            LOG.error(u'Caught ConnectionError, maximum attempts '
-                      'to {0} exceeded.'.format(func))
+            LOG.error('Caught ConnectionError, maximum attempts '
+                      'to %s exceeded.', func.__name__)
             raise ex
 
     return wrapper
diff --git a/zaqar/tests/unit/storage/sqlalchemy_migration/test_migrations_base.py b/zaqar/tests/unit/storage/sqlalchemy_migration/test_migrations_base.py
index a1b319ef2..1015d3f27 100644
--- a/zaqar/tests/unit/storage/sqlalchemy_migration/test_migrations_base.py
+++ b/zaqar/tests/unit/storage/sqlalchemy_migration/test_migrations_base.py
@@ -83,8 +83,8 @@ class BaseWalkMigrationTestCase(object):
 
         getattr(command, alembic_command)(*args, **kwargs)
         res = buf.getvalue().strip()
-        LOG.debug('Alembic command {command} returns: {result}'.format(
-                  command=alembic_command, result=res))
+        LOG.debug('Alembic command {command} returns: {result}',
+                  {'command': alembic_command, 'result': res})
 
         return res
 
@@ -160,7 +160,7 @@ class BaseWalkMigrationTestCase(object):
                     check(engine, data)
         except Exception:
             LOG.error("Failed to migrate to version {version} on engine "
-                      "{engine}".format(version=version, engine=engine))
+                      "{engine}", {'version': version, 'engine': engine})
             raise
 
 
diff --git a/zaqar/tests/unit/transport/wsgi/v2_0/test_flavors_new.py b/zaqar/tests/unit/transport/wsgi/v2_0/test_flavors_new.py
index 6546631ad..e745abb3a 100644
--- a/zaqar/tests/unit/transport/wsgi/v2_0/test_flavors_new.py
+++ b/zaqar/tests/unit/transport/wsgi/v2_0/test_flavors_new.py
@@ -266,7 +266,7 @@ class TestFlavorsMongoDB(base.V2Base):
         self.simulate_delete(self.flavor_path)
         query = 'limit={0}&detailed={1}'.format(limit, detailed)
         if marker:
-            query += '&marker={2}'.format(marker)
+            query += '&marker={0}'.format(marker)
 
         with flavors(self, count):
             result = self.simulate_get(self.url_prefix + '/flavors',
diff --git a/zaqar/tests/unit/transport/wsgi/v2_0/test_subscriptions.py b/zaqar/tests/unit/transport/wsgi/v2_0/test_subscriptions.py
index 77c7d82e7..4451a7d93 100644
--- a/zaqar/tests/unit/transport/wsgi/v2_0/test_subscriptions.py
+++ b/zaqar/tests/unit/transport/wsgi/v2_0/test_subscriptions.py
@@ -186,7 +186,7 @@ class TestSubscriptionsMongoDB(base.V2Base):
 
         query = 'limit={0}'.format(limit)
         if marker:
-            query += '&marker={1}'.format(marker)
+            query += '&marker={0}'.format(marker)
 
         resp = self.simulate_get(self.subscription_path,
                                  query_string=query,