[SEBA-450] (part 2)

Add tox testing support on additional XOS library modules:

- xos-api
- xos-kafka (has no tests)
- xos-migrate (has no tests)
- xos-synchronizer

Change-Id: I98195bc9747971d3515882d517affe058dd86ac5
diff --git a/lib/xos-synchronizer/xossynchronizer/steps/syncstep.py b/lib/xos-synchronizer/xossynchronizer/steps/syncstep.py
index 7644822..08637ed 100644
--- a/lib/xos-synchronizer/xossynchronizer/steps/syncstep.py
+++ b/lib/xos-synchronizer/xossynchronizer/steps/syncstep.py
@@ -13,9 +13,12 @@
 # limitations under the License.
 
 
-from xosconfig import Config
+from __future__ import absolute_import
+
 from functools import reduce
 
+from xosconfig import Config
+
 
 def f7(seq):
     seen = set()
@@ -113,7 +116,6 @@
                 result.append(class_or_name)
         return result
 
-
     def fetch_pending(self, deletion=False):
         # This is the most common implementation of fetch_pending
         # Steps should override it if they have their own logic
@@ -121,12 +123,10 @@
 
         return self.model_accessor.fetch_pending(self.observes_classes, deletion)
 
-
     def sync_record(self, o):
         self.log.debug("In abstract sync record", **o.tologdict())
         # This method should be overridden by the service
 
-
     def delete_record(self, o):
         self.log.debug("In abstract delete record", **o.tologdict())
         # This method should be overridden by the service