fix unit test and code style changes

shards/conftest.py

@@ -25,6 +25,7 @@ def app(request):
     yield app
 
     db.drop_all()
+    app.stop()
     # shutil.rmtree(tpath)
 
 

shards/tracer/factory.py

@@ -2,6 +2,7 @@ import os
 import logging
 from functools import partial
 from pluginbase import PluginBase
+from tracer import Tracer
 
 
 logger = logging.getLogger(__name__)
@@ -13,14 +14,15 @@ PLUGIN_PACKAGE_NAME = 'tracer.plugins'
 plugin_base = PluginBase(package=PLUGIN_PACKAGE_NAME,
                          searchpath=[get_path('./plugins')])
 
+
 class TracerFactory(object):
     def __init__(self, searchpath=None):
         self.plugin_package_name = PLUGIN_PACKAGE_NAME
         self.tracer_map = {}
         searchpath = searchpath if searchpath else []
         searchpath = [searchpath] if isinstance(searchpath, str) else searchpath
-        self.source = plugin_base.make_plugin_source(
-                searchpath=searchpath, identifier=self.__class__.__name__)
+        self.source = plugin_base.make_plugin_source(searchpath=searchpath,
+                                                     identifier=self.__class__.__name__)
 
         for plugin_name in self.source.list_plugins():
             plugin = self.source.load_plugin(plugin_name)

shards/tracer/plugins/jaeger_factory.py

@@ -8,6 +8,7 @@ logger = logging.getLogger(__name__)
 
 PLUGIN_NAME = __file__
 
+
 class JaegerFactory:
     name = 'jaeger'
     @classmethod