diff --git a/.travis.yml b/.travis.yml
index 6520fddcb..7240c3d21 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,7 +2,9 @@ language: python
 sudo: required
 
 python:
-  - "3"
+  - "3.6"
+  - "3.7"
+  - "3.8"
 
 install:
   - pip install tox codecov
diff --git a/dolphin/alert_manager/alert_processor.py b/dolphin/alert_manager/alert_processor.py
index 71b06410e..281e63fe4 100644
--- a/dolphin/alert_manager/alert_processor.py
+++ b/dolphin/alert_manager/alert_processor.py
@@ -47,13 +47,13 @@ def process_alert_info(self, alert):
             access_info = db.access_info_get_all(ctxt, filters=filters)
         except Exception:
             msg = "Access information could not be found with host %s." \
-                    % alert['transport_address']
+                  % alert['transport_address']
             raise exception.AccessInfoNotFound(message=msg)
 
         # For given source ip, there should be unique access_info
         if len(access_info) != 1:
             msg = "Failed to get unique access information with host %s." \
-                    % alert['transport_address']
+                  % alert['transport_address']
             raise exception.InvalidResults(message=msg)
 
         try:
@@ -80,4 +80,3 @@ def process_alert_info(self, alert):
     def _export_alert_model(self, alert_model):
         """Exports the filled alert model to the export manager."""
         LOG.info('Alert model to be exported: %s.', alert_model)
-
diff --git a/dolphin/alert_manager/constants.py b/dolphin/alert_manager/constants.py
index f783a7dd2..365039a63 100644
--- a/dolphin/alert_manager/constants.py
+++ b/dolphin/alert_manager/constants.py
@@ -19,13 +19,13 @@
 TRAP_RECEIVER_CLASS = 'dolphin.alert_manager.trap_receiver.TrapReceiver'
 
 # Temporary snmp community and user configurations
-SNMP_COMMUNITY_STR='public'
-SNMP_USM_USER='test1'
-SNMP_V3_AUTHKEY='abcd123456'
-SNMP_V3_PRIVKEY='abcd123456'
-SNMP_V3_AUTH_PROTOCOL='usmHMACMD5AuthProtocol'
-SNMP_V3_PRIV_PROTOCOL='usmDESPrivProtocol'
-SNMP_ENGINE_ID='800000d30300000e112245'
+SNMP_COMMUNITY_STR = 'public'
+SNMP_USM_USER = 'test1'
+SNMP_V3_AUTHKEY = 'abcd123456'
+SNMP_V3_PRIVKEY = 'abcd123456'
+SNMP_V3_AUTH_PROTOCOL = 'usmHMACMD5AuthProtocol'
+SNMP_V3_PRIV_PROTOCOL = 'usmDESPrivProtocol'
+SNMP_ENGINE_ID = '800000d30300000e112245'
 
 # Temporary mib lod dir. This mechanism to be changed later
 SNMP_MIB_PATH = '/usr/local/lib/python3.6/dist-packages/pysnmp/smi/mibs'
diff --git a/dolphin/alert_manager/trap_receiver.py b/dolphin/alert_manager/trap_receiver.py
index 692abe843..df0cade49 100644
--- a/dolphin/alert_manager/trap_receiver.py
+++ b/dolphin/alert_manager/trap_receiver.py
@@ -29,7 +29,7 @@
 
 # Currently static mib file list is loaded
 # Mechanism to be changed to load all mib file
-MIB_LOAD_LIST = ['SNMPv2-MIB','IF_MIB']
+MIB_LOAD_LIST = ['SNMPv2-MIB', 'IF_MIB']
 
 
 class TrapReceiver(object):
@@ -109,8 +109,8 @@ def _cb_fun(self, state_reference, context_engine_id, context_name,
                      context_name.prettyPrint(), exec_context['securityModel'],
                      exec_context['securityName']))
 
-        var_binds = [rfc1902.ObjectType(rfc1902.ObjectIdentity(x[0]), x[1])
-                         .resolveWithMib(self.mib_view_controller)
+        var_binds = [rfc1902.ObjectType(rfc1902.ObjectIdentity(x[0]),
+                                        x[1]).resolveWithMib(self.mib_view_controller)
                      for x in var_binds]
         alert = {}
 
diff --git a/dolphin/api/api_utils.py b/dolphin/api/api_utils.py
index b33ce3860..2a306bcf7 100644
--- a/dolphin/api/api_utils.py
+++ b/dolphin/api/api_utils.py
@@ -20,6 +20,7 @@
 from oslo_utils import strutils
 
 from dolphin.common import constants
+from dolphin.i18n import _
 
 api_common_opts = [
     cfg.IntOpt('api_max_limit',
diff --git a/dolphin/api/common/wsgi.py b/dolphin/api/common/wsgi.py
index 5b7b53605..32c5544c0 100644
--- a/dolphin/api/common/wsgi.py
+++ b/dolphin/api/common/wsgi.py
@@ -175,7 +175,7 @@ def best_match_content_type(self):
                 content_type = self.accept.best_match(SUPPORTED_CONTENT_TYPES)
 
             self.environ['dolphin.best_content_type'] = (content_type or
-                                                        'application/json')
+                                                         'application/json')
 
         return self.environ['dolphin.best_content_type']
 
@@ -262,6 +262,7 @@ def decorator(func):
             func.wsgi_serializers = {}
         func.wsgi_serializers.update(serializers)
         return func
+
     return decorator
 
 
@@ -278,6 +279,7 @@ def decorator(func):
             func.wsgi_deserializers = {}
         func.wsgi_deserializers.update(deserializers)
         return func
+
     return decorator
 
 
@@ -292,6 +294,7 @@ def response(code):
     def decorator(func):
         func.wsgi_code = code
         return func
+
     return decorator
 
 
@@ -845,6 +848,7 @@ def action(name):
     def decorator(func):
         func.wsgi_action = name
         return func
+
     return decorator
 
 
diff --git a/dolphin/api/extensions.py b/dolphin/api/extensions.py
index a445ead2e..16769060a 100644
--- a/dolphin/api/extensions.py
+++ b/dolphin/api/extensions.py
@@ -326,4 +326,3 @@ def load_standard_extensions(ext_mgr, logger, path, package, ext_list=None):
 
         # Update the list of directories we'll explore...
         dirnames[:] = subdirs
-
diff --git a/dolphin/api/schemas/alert.py b/dolphin/api/schemas/alert.py
index 5118e2b9b..370995bb1 100644
--- a/dolphin/api/schemas/alert.py
+++ b/dolphin/api/schemas/alert.py
@@ -32,4 +32,3 @@
     'required': ['host', 'version'],
     'additionalProperties': False,
 }
-
diff --git a/dolphin/api/v1/alert.py b/dolphin/api/v1/alert.py
index 64e3ad688..187186247 100644
--- a/dolphin/api/v1/alert.py
+++ b/dolphin/api/v1/alert.py
@@ -52,7 +52,7 @@ def put(self, req, id, body):
                 alert_source = db.alert_source_update(ctx, id, alert_source)
             else:
                 alert_source = db.alert_source_create(ctx, alert_source)
-        except exception.StorageNotFound as e:
+        except exception.StorageNotFound:
             msg = (_("Alert source cannot be created or updated for a"
                      " non-existing storage %s.") % id)
             raise exc.HTTPBadRequest(explanation=msg)
diff --git a/dolphin/api/v1/pools.py b/dolphin/api/v1/pools.py
index ec61e9a68..909a216ed 100644
--- a/dolphin/api/v1/pools.py
+++ b/dolphin/api/v1/pools.py
@@ -20,7 +20,6 @@
 from dolphin.api import api_utils
 from dolphin.api.common import wsgi
 from dolphin.api.views import pools as pool_view
-from dolphin.i18n import _
 
 
 class PoolController(wsgi.Controller):
@@ -53,7 +52,7 @@ def index(self, req):
         try:
             pools = db.pool_get_all(ctxt, marker, limit, sort_keys, sort_dirs,
                                     query_params, offset)
-        except  exception.InvalidInput as e:
+        except exception.InvalidInput as e:
             raise exc.HTTPBadRequest(explanation=six.text_type(e))
         return pool_view.build_pools(pools)
 
diff --git a/dolphin/api/v1/storages.py b/dolphin/api/v1/storages.py
index cd0d68bc9..236c5dc42 100644
--- a/dolphin/api/v1/storages.py
+++ b/dolphin/api/v1/storages.py
@@ -64,7 +64,6 @@ def _get_storages_search_options(self):
 
     def index(self, req):
         ctxt = req.environ['dolphin.context']
-        supported_filters = ['name', 'vendor', 'model', 'status']
         query_params = {}
         query_params.update(req.GET)
         # update options  other than filters
@@ -76,7 +75,7 @@ def index(self, req):
         try:
             storages = db.storage_get_all(context, marker, limit, sort_keys,
                                           sort_dirs, query_params, offset)
-        except  exception.InvalidInput as e:
+        except exception.InvalidInput as e:
             raise exc.HTTPBadRequest(explanation=six.text_type(e))
         return storage_view.build_storages(storages)
 
diff --git a/dolphin/api/v1/volumes.py b/dolphin/api/v1/volumes.py
index c2858b7ed..d7553ebe4 100644
--- a/dolphin/api/v1/volumes.py
+++ b/dolphin/api/v1/volumes.py
@@ -26,5 +26,3 @@ def show(self, req, id):
 
 def create_resource():
     return wsgi.Resource(VolumeController())
-
-
diff --git a/dolphin/cmd/api.py b/dolphin/cmd/api.py
index 0d0815876..22d5965ee 100644
--- a/dolphin/cmd/api.py
+++ b/dolphin/cmd/api.py
@@ -26,7 +26,7 @@
 from oslo_config import cfg
 from oslo_log import log
 
-from dolphin.common import config  # Need to register global_opts
+from dolphin.common import config  # noqa
 from dolphin import service
 from dolphin import utils
 from dolphin import version
@@ -47,7 +47,7 @@ def main():
     launcher.launch_service(api_server, workers=api_server.workers or 1)
     launcher.launch_service(task_server)
 
-    #Launch alert manager service
+    # Launch alert manager service
     alert_manager = service.AlertMngrService()
     launcher.launch_service(alert_manager)
 
diff --git a/dolphin/coordination.py b/dolphin/coordination.py
index 8b4844b44..5aea55779 100644
--- a/dolphin/coordination.py
+++ b/dolphin/coordination.py
@@ -25,10 +25,8 @@
 from dolphin import exception
 from dolphin.i18n import _
 
-
 LOG = log.getLogger(__name__)
 
-
 coordination_opts = [
     cfg.StrOpt('backend_url',
                default='redis://127.0.0.1:6379',
@@ -117,6 +115,7 @@ class Lock(locking.Lock):
 
     Available field names are keys of lock_data.
     """
+
     def __init__(self, lock_name, lock_data=None, coordinator=None):
         super(Lock, self).__init__(six.text_type(id(self)))
         lock_data = lock_data or {}
@@ -191,6 +190,7 @@ def foo(self, shr, snap):
     Available field names are: decorated function parameters and
     `f_name` as a decorated function name.
     """
+
     @decorator.decorator
     def _synchronized(f, *a, **k):
         call_args = inspect.getcallargs(f, *a, **k)
@@ -198,6 +198,7 @@ def _synchronized(f, *a, **k):
         lock = Lock(lock_name, call_args, coordinator)
         with lock(blocking):
             LOG.info('Lock "%(name)s" acquired by "%(function)s".',
-                      {'name': lock_name, 'function': f.__name__})
+                     {'name': lock_name, 'function': f.__name__})
             return f(*a, **k)
+
     return _synchronized
diff --git a/dolphin/db/sqlalchemy/api.py b/dolphin/db/sqlalchemy/api.py
index b6a9bd8c0..2d6b8bd09 100755
--- a/dolphin/db/sqlalchemy/api.py
+++ b/dolphin/db/sqlalchemy/api.py
@@ -47,9 +47,9 @@
 
 def apply_sorting(model, query, sort_key, sort_dir):
     if sort_dir.lower() not in ('desc', 'asc'):
-        msg = ("Wrong sorting data provided: sort key is '%(sort_key)s' "
-               "and sort order is '%(sort_dir)s'.") % {
-                  "sort_key": sort_key, "sort_dir": sort_dir}
+        msg = (("Wrong sorting data provided: sort key is '%(sort_key)s' "
+                "and sort order is '%(sort_dir)s'.") %
+               {"sort_key": sort_key, "sort_dir": sort_dir})
         raise exception.InvalidInput(reason=msg)
 
     sort_attr = getattr(model, sort_key)
@@ -181,7 +181,7 @@ def access_info_update(context, storage_id, values):
 
 def access_info_delete(context, storage_id):
     """Delete a storage access information."""
-    _access_info_get_query(context).\
+    _access_info_get_query(context). \
         filter_by(storage_id=storage_id).delete()
 
 
@@ -397,11 +397,7 @@ def volumes_update(context, volumes):
 
 def volume_get(context, volume_id):
     """Get a volume or raise an exception if it does not exist."""
-    return _volume_get(context, vol_id)
-
-
-def _volume_get_query(context, session=None):
-    return model_query(context, models.Volume, session=session)
+    return _volume_get(context, volume_id)
 
 
 def volume_get_all(context, marker=None, limit=None, sort_keys=None,
@@ -412,8 +408,7 @@ def volume_get_all(context, marker=None, limit=None, sort_keys=None,
         # Generate the query
         query = _generate_paginate_query(context, session, models.Volume,
                                          marker, limit, sort_keys, sort_dirs,
-                                         filters, offset
-                                         )
+                                         filters, offset)
         # No volume would match, return empty list
         if query is None:
             return []
@@ -682,7 +677,7 @@ def alert_source_delete(context, storage_id):
 
 
 def alert_source_get_all(context, marker=None, limit=None, sort_keys=None,
-                    sort_dirs=None, filters=None, offset=None):
+                         sort_dirs=None, filters=None, offset=None):
     session = get_session()
     with session.begin():
         query = _generate_paginate_query(context, session, models.AlertSource,
diff --git a/dolphin/db/sqlalchemy/models.py b/dolphin/db/sqlalchemy/models.py
index bb13c4b36..10523081f 100755
--- a/dolphin/db/sqlalchemy/models.py
+++ b/dolphin/db/sqlalchemy/models.py
@@ -18,7 +18,6 @@
 """
 SQLAlchemy models for Dolphin  data.
 """
-import json
 
 from oslo_config import cfg
 from oslo_db.sqlalchemy import models
diff --git a/dolphin/drivers/api.py b/dolphin/drivers/api.py
index cb1555081..ba021b6f1 100644
--- a/dolphin/drivers/api.py
+++ b/dolphin/drivers/api.py
@@ -70,12 +70,12 @@ def remove_storage(self, context, storage_id):
 
     def get_storage(self, context, storage_id):
         """Get storage device information from storage system"""
-        driver = self.driver_manager.get_driver(context, storage_id)
+        driver = self.driver_manager.get_driver(context, storage_id=storage_id)
         return driver.get_storage(context)
 
     def list_pools(self, context, storage_id):
         """List all storage pools from storage system."""
-        driver = self.driver_manager.get_driver(context, storage_id)
+        driver = self.driver_manager.get_driver(context, storage_id=storage_id)
         return driver.list_pools(context)
 
     def list_volumes(self, context, storage_id):
@@ -92,11 +92,9 @@ def remove_trap_config(self, context, storage_id, trap_config):
 
     def parse_alert(self, context, storage_id, alert):
         """Parse alert data got from snmp trap server."""
-        driver = self.driver_manager.get_driver(context, **{'storage_id': storage_id})
+        driver = self.driver_manager.get_driver(context, storage_id=storage_id)
         driver.parse_alert(context, alert)
 
     def clear_alert(self, context, storage_id, alert):
         """Clear alert from storage system."""
         pass
-
-
diff --git a/dolphin/drivers/dell_emc/vmax/client.py b/dolphin/drivers/dell_emc/vmax/client.py
index c03c402d3..fd414eb08 100644
--- a/dolphin/drivers/dell_emc/vmax/client.py
+++ b/dolphin/drivers/dell_emc/vmax/client.py
@@ -12,21 +12,22 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import json
 import PyU4V
 
-from dolphin import exception
-from dolphin.common import constants
 from oslo_log import log
 from oslo_utils import units
 
+from dolphin import exception
+from dolphin.common import constants
+
 LOG = log.getLogger(__name__)
 
-SUPPORTED_VERSION='90'
+SUPPORTED_VERSION = '90'
 
 
 class VMAXClient(object):
     """ Client class for communicating with VMAX storage """
+
     def __init__(self):
         self.conn = None
         self.array_id = None
@@ -39,8 +40,8 @@ def __del__(self):
 
     def init_connection(self, access_info):
         """ Given the access_info get a connection to VMAX storage """
-        self.array_id = access_info.get('extra_attributes', {}).\
-                                get('array_id', None)
+        self.array_id = access_info.get('extra_attributes', {}). \
+            get('array_id', None)
         if not self.array_id:
             raise exception.InvalidInput(reason='Input array_id is missing')
 
diff --git a/dolphin/drivers/dell_emc/vmax/vmax.py b/dolphin/drivers/dell_emc/vmax/vmax.py
index 50345ab5b..5ede9928b 100644
--- a/dolphin/drivers/dell_emc/vmax/vmax.py
+++ b/dolphin/drivers/dell_emc/vmax/vmax.py
@@ -33,19 +33,6 @@ def __init__(self, **kwargs):
     def _init_vmax(self, access_info):
         self.client.init_connection(access_info)
 
-        # Get the VMAX version to check connection
-        version = self.client.get_version()
-
-    @staticmethod
-    def get_storage_registry():
-        required_register_attributes = super.get_storage_registry()
-        extra_attributes = {
-            'array_id': "The storage id in unisphere system.",
-        }
-        required_register_attributes['extra_attributes'] = extra_attributes
-
-        return  required_register_attributes
-
     def get_storage(self, context):
 
         # Get the VMAX model
diff --git a/dolphin/service.py b/dolphin/service.py
index b403a213e..7b80ee3c8 100644
--- a/dolphin/service.py
+++ b/dolphin/service.py
@@ -20,20 +20,18 @@
 import inspect
 import os
 import random
-import socket
 
+import oslo_messaging as messaging
 from oslo_config import cfg
 from oslo_log import log
+from oslo_service import loopingcall
 from oslo_service import service
 from oslo_service import wsgi
-from oslo_service import loopingcall
 from oslo_utils import importutils
-import oslo_messaging as messaging
 
 from dolphin import context
-from dolphin import exception
-from dolphin import rpc
 from dolphin import coordination
+from dolphin import rpc
 from dolphin.alert_manager import constants
 
 LOG = log.getLogger(__name__)
@@ -218,6 +216,7 @@ def periodic_tasks(self, raise_on_error=False):
         ctxt = context.get_admin_context()
         self.manager.periodic_tasks(ctxt, raise_on_error=raise_on_error)
 
+
 class AlertMngrService(service.Service):
     """Service object for triggering trap receiver functionalities.
     """
@@ -253,6 +252,7 @@ def stop(self):
         """Calls the shutdown flow of the service."""
         self.manager.stop()
 
+
 class WSGIService(service.ServiceBase):
     """Provides ability to launch API from a 'paste' configuration."""
 
diff --git a/dolphin/task_manager/manager.py b/dolphin/task_manager/manager.py
index 1ea4e48f5..81752f194 100644
--- a/dolphin/task_manager/manager.py
+++ b/dolphin/task_manager/manager.py
@@ -63,7 +63,7 @@ def say_hello(self, context, request_spec=None,
             # report data to northbound platform
             base_exporter.dispatch_example_data(data)
 
-        except Exception as ex:
+        except Exception:
             pass
 
     def sync_storage_resource(self, context, storage_id, resource_task):
diff --git a/dolphin/task_manager/tasks/task.py b/dolphin/task_manager/tasks/task.py
index 75f8df6fa..23cdcb381 100644
--- a/dolphin/task_manager/tasks/task.py
+++ b/dolphin/task_manager/tasks/task.py
@@ -128,11 +128,6 @@ def remove(self):
         db.pool_delete_by_storage(self.context, self.storage_id)
 
 
-class StorageVolumeTask(StorageResourceTask):
-    def sync(self):
-        pass
-
-
 class StorageVolumeTask(StorageResourceTask):
     def __init__(self, context, storage_id):
         super(StorageVolumeTask, self).__init__(context, storage_id)
diff --git a/dolphin/tests/api/__init__.py b/dolphin/tests/unit/__init__.py
similarity index 100%
rename from dolphin/tests/api/__init__.py
rename to dolphin/tests/unit/__init__.py
diff --git a/dolphin/tests/api/v1/__init__.py b/dolphin/tests/unit/api/__init__.py
similarity index 100%
rename from dolphin/tests/api/v1/__init__.py
rename to dolphin/tests/unit/api/__init__.py
diff --git a/dolphin/tests/unit/api/v1/__init__.py b/dolphin/tests/unit/api/v1/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/dolphin/tests/api/v1/test_storages.py b/dolphin/tests/unit/api/v1/test_storages.py
similarity index 100%
rename from dolphin/tests/api/v1/test_storages.py
rename to dolphin/tests/unit/api/v1/test_storages.py
diff --git a/dolphin/utils.py b/dolphin/utils.py
index 2abfa497a..ef629ad5b 100644
--- a/dolphin/utils.py
+++ b/dolphin/utils.py
@@ -27,7 +27,6 @@
 import shutil
 import sys
 import tempfile
-import time
 import threading
 
 from eventlet import pools
@@ -481,6 +480,7 @@ def retry(exception, interval=1, retries=10, backoff_rate=2,
     :param backoff_sleep_max: Maximum number of seconds for the calculated
                               backoff sleep. Use None if no maximum is needed.
     """
+
     def _retry_on_exception(e):
         return isinstance(e, exception)
 
@@ -578,6 +578,7 @@ def wrapper(self, *args, **kwargs):
             driver_name = self.driver.__class__.__name__
             raise exception.DriverNotInitialized(driver=driver_name)
         return func(self, *args, **kwargs)
+
     return wrapper
 
 
@@ -666,11 +667,13 @@ def notifications_enabled(conf):
 
 def if_notifications_enabled(function):
     """Calls decorated method only if notifications are enabled."""
+
     @functools.wraps(function)
     def wrapped(*args, **kwargs):
         if notifications_enabled(CONF):
             return function(*args, **kwargs)
         return DO_NOTHING
+
     return wrapped
 
 
diff --git a/pytest.ini b/pytest.ini
index b759cd8f1..e52271e8b 100644
--- a/pytest.ini
+++ b/pytest.ini
@@ -1,4 +1,3 @@
 [pytest]
 usefixtures = cache
 python_files = test_*.py __init__.py
-addopts = -p no:warnings
diff --git a/tox.ini b/tox.ini
index 3a03d7752..ecffdb6f1 100644
--- a/tox.ini
+++ b/tox.ini
@@ -2,7 +2,7 @@
 skipsdist = True
 skip_missing_interpreters = True
 envlist =
-    py3
+    py3,
     pep8
 
 [testenv]
@@ -20,5 +20,5 @@ deps = flake8
 commands = flake8 {posargs:dolphin}
 
 [flake8]
-ignore = E402
+ignore = E402,W503,W504
 max-line-length = 120