diff --git a/conftest.py b/conftest.py
index d6c9f3acc7..1aba5b32cf 100644
--- a/conftest.py
+++ b/conftest.py
@@ -1,5 +1,6 @@
 import logging
 import pytest
+import grpc
 from mishards import settings, db, create_app
 
 logger = logging.getLogger(__name__)
@@ -14,3 +15,12 @@ def app(request):
     yield app
 
     db.drop_all()
+
+@pytest.fixture
+def started_app(app):
+    app.on_pre_run()
+    app.start(app.port)
+
+    yield app
+
+    app.stop()
diff --git a/mishards/__init__.py b/mishards/__init__.py
index 47d8adb6e3..4bd77d8c60 100644
--- a/mishards/__init__.py
+++ b/mishards/__init__.py
@@ -24,7 +24,7 @@ def create_app(testing_config=None):
 
     from tracing.factory import TracerFactory
     from mishards.grpc_utils import GrpcSpanDecorator
-    tracer = TracerFactory.new_tracer(settings.TRACING_TYPE, settings.TracingConfig,
+    tracer = TracerFactory.new_tracer(config.TRACING_TYPE, settings.TracingConfig,
                                       span_decorator=GrpcSpanDecorator())
 
     grpc_server.init_app(conn_mgr=connect_mgr, tracer=tracer, discover=discover)
diff --git a/mishards/connections.py b/mishards/connections.py
index 22263e9e7e..7db271381c 100644
--- a/mishards/connections.py
+++ b/mishards/connections.py
@@ -18,7 +18,7 @@ class Connection:
         self.conn = Milvus()
         self.error_handlers = [] if not error_handlers else error_handlers
         self.on_retry_func = kwargs.get('on_retry_func', None)
-        self._connect()
+        # self._connect()
 
     def __str__(self):
         return 'Connection:name=\"{}\";uri=\"{}\"'.format(self.name, self.uri)
diff --git a/mishards/grpc_utils/test_grpc.py b/mishards/grpc_utils/test_grpc.py
index 068ee391e7..d8511c8d6c 100644
--- a/mishards/grpc_utils/test_grpc.py
+++ b/mishards/grpc_utils/test_grpc.py
@@ -57,7 +57,6 @@ class TestGrpcUtils:
         span = TestSpan(context=None, tracer=TestTracer())
         span_deco = GrpcSpanDecorator()
         span_deco(span, rpc_info)
-        logger.error(span.logs)
         assert len(span.logs) == 1
         assert len(span.tags) == 1
 
@@ -66,7 +65,6 @@ class TestGrpcUtils:
         span = TestSpan(context=None, tracer=TestTracer())
         span_deco = GrpcSpanDecorator()
         span_deco(span, rpc_info)
-        logger.error(span.logs)
         assert len(span.logs) == 0
         assert len(span.tags) == 0
 
diff --git a/mishards/main.py b/mishards/main.py
index 3f69484ee4..c0d142607b 100644
--- a/mishards/main.py
+++ b/mishards/main.py
@@ -6,8 +6,7 @@ from mishards import (settings, create_app)
 
 
 def main():
-    server = create_app(
-        settings.TestingConfig if settings.TESTING else settings.DefaultConfig)
+    server = create_app(settings.DefaultConfig)
     server.run(port=settings.SERVER_PORT)
     return 0
 
diff --git a/mishards/server.py b/mishards/server.py
index feb2176e86..dcaacd0fbc 100644
--- a/mishards/server.py
+++ b/mishards/server.py
@@ -39,7 +39,7 @@ class Server:
         self.register_pre_run_handler(self.pre_run_handler)
 
     def pre_run_handler(self):
-        woserver = settings.WOSERVER if not settings.TESTING else settings.TESTING_WOSERVER
+        woserver = settings.WOSERVER
         url = urlparse(woserver)
         ip = socket.gethostbyname(url.hostname)
         socket.inet_pton(socket.AF_INET, ip)
diff --git a/mishards/settings.py b/mishards/settings.py
index 1982a508e7..c9b62717d4 100644
--- a/mishards/settings.py
+++ b/mishards/settings.py
@@ -43,10 +43,7 @@ elif SD_PROVIDER == 'Static':
     SD_PROVIDER_SETTINGS = StaticProviderSettings(
         hosts=env.list('SD_STATIC_HOSTS', []))
 
-TESTING = env.bool('TESTING', False)
-TESTING_WOSERVER = env.str('TESTING_WOSERVER', 'tcp://127.0.0.1:19530')
-
-TRACING_TYPE = env.str('TRACING_TYPE', '')
+# TESTING_WOSERVER = env.str('TESTING_WOSERVER', 'tcp://127.0.0.1:19530')
 
 
 class TracingConfig:
@@ -64,19 +61,24 @@ class TracingConfig:
         },
         'logging': env.bool('TRACING_LOGGING', True)
     }
+    DEFAULT_TRACING_CONFIG = {
+        'sampler': {
+            'type': env.str('TRACING_SAMPLER_TYPE', 'const'),
+            'param': env.str('TRACING_SAMPLER_PARAM', "0"),
+        }
+    }
 
 
 class DefaultConfig:
     SQLALCHEMY_DATABASE_URI = env.str('SQLALCHEMY_DATABASE_URI')
     SQL_ECHO = env.bool('SQL_ECHO', False)
+    TRACING_TYPE = env.str('TRACING_TYPE', '')
 
 
-TESTING = env.bool('TESTING', False)
-if TESTING:
-
-    class TestingConfig(DefaultConfig):
-        SQLALCHEMY_DATABASE_URI = env.str('SQLALCHEMY_DATABASE_TEST_URI')
-        SQL_ECHO = env.bool('SQL_TEST_ECHO', False)
+class TestingConfig(DefaultConfig):
+    SQLALCHEMY_DATABASE_URI = env.str('SQLALCHEMY_DATABASE_TEST_URI')
+    SQL_ECHO = env.bool('SQL_TEST_ECHO', False)
+    TRACING_TYPE = env.str('TRACING_TEST_TYPE', '')
 
 
 if __name__ == '__main__':
diff --git a/mishards/test_connections.py b/mishards/test_connections.py
index f1c54f0c61..819d2e03da 100644
--- a/mishards/test_connections.py
+++ b/mishards/test_connections.py
@@ -1,6 +1,8 @@
 import logging
 import pytest
+import mock
 
+from milvus import Milvus
 from mishards.connections import (ConnectionMgr, Connection)
 from mishards import exceptions
 
@@ -27,6 +29,12 @@ class TestConnection:
         mgr.register('WOSERVER', 'xxxx')
         assert len(mgr.conn_names) == 0
 
+        assert not mgr.conn('XXXX', None)
+        with pytest.raises(exceptions.ConnectionNotFoundError):
+            mgr.conn('XXXX', None, True)
+
+        mgr.conn('WOSERVER', None)
+
     def test_connection(self):
         class Conn:
             def __init__(self, state):
@@ -37,6 +45,7 @@ class TestConnection:
 
             def connected(self):
                 return self.state
+
         FAIL_CONN = Conn(False)
         PASS_CONN = Conn(True)
 
@@ -58,7 +67,9 @@ class TestConnection:
         max_retry = 3
 
         RetryObj = Retry()
-        c = Connection('client', uri='',
+
+        c = Connection('client',
+                       uri='xx',
                        max_retry=max_retry,
                        on_retry_func=RetryObj)
         c.conn = FAIL_CONN
@@ -75,3 +86,16 @@ class TestConnection:
         this_connect()
         assert ff.executed
         assert RetryObj.times == 0
+
+        this_connect = c.connect(func=None)
+        with pytest.raises(TypeError):
+            this_connect()
+
+        errors = []
+
+        def error_handler(err):
+            errors.append(err)
+
+        this_connect = c.connect(func=None, exception_handler=error_handler)
+        this_connect()
+        assert len(errors) == 1
diff --git a/requirements.txt b/requirements.txt
index ea338d0723..133cfac8ab 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -33,3 +33,4 @@ SQLAlchemy==1.3.5
 urllib3==1.25.3
 jaeger-client>=3.4.0
 grpcio-opentracing>=1.0
+mock==2.0.0
diff --git a/tracing/factory.py b/tracing/factory.py
index 648dfa291e..0c14d9d536 100644
--- a/tracing/factory.py
+++ b/tracing/factory.py
@@ -12,13 +12,17 @@ logger = logging.getLogger(__name__)
 class TracerFactory:
     @classmethod
     def new_tracer(cls, tracer_type, tracer_config, span_decorator=None, **kwargs):
+        config = tracer_config.TRACING_CONFIG
+        service_name = tracer_config.TRACING_SERVICE_NAME
+        validate=tracer_config.TRACING_VALIDATE
         if not tracer_type:
-            return Tracer()
+            tracer_type = 'jaeger'
+            config = tracer_config.DEFAULT_TRACING_CONFIG
 
         if tracer_type.lower() == 'jaeger':
-            config = Config(config=tracer_config.TRACING_CONFIG,
-                            service_name=tracer_config.TRACING_SERVICE_NAME,
-                            validate=tracer_config.TRACING_VALIDATE
+            config = Config(config=config,
+                            service_name=service_name,
+                            validate=validate
                             )
 
             tracer = config.initialize_tracer()