diff --git a/freqtrade/exchange/__init__.py b/freqtrade/exchange/__init__.py
index 670d9d3a5..139b1c667 100644
--- a/freqtrade/exchange/__init__.py
+++ b/freqtrade/exchange/__init__.py
@@ -114,7 +114,8 @@ class Exchange(object):
             if api.urls.get('test'):
                 api.urls['api'] = api.urls['test']
             else:
-                logger.warning(self, "No Sandbox URL in CCXT, exiting. Please check your config.json")
+                logger.warning(self, "No Sandbox URL in CCXT, exiting. "
+                                     "Please check your config.json")
                 raise OperationalException(f'Exchange {name} does not provide a sandbox api')
 
     def validate_pairs(self, pairs: List[str]) -> None:
diff --git a/freqtrade/tests/exchange/test_exchange.py b/freqtrade/tests/exchange/test_exchange.py
index 862229bea..2c58d928c 100644
--- a/freqtrade/tests/exchange/test_exchange.py
+++ b/freqtrade/tests/exchange/test_exchange.py
@@ -51,6 +51,7 @@ def test_init_exception(default_conf, mocker):
         mocker.patch("ccxt.binance", MagicMock(side_effect=AttributeError))
         Exchange(default_conf)
 
+
 def test_set_sandbox(default_conf, mocker):
     """
     Test working scenario
@@ -59,7 +60,8 @@ def test_set_sandbox(default_conf, mocker):
     api_mock.load_markets = MagicMock(return_value={
         'ETH/BTC': '', 'LTC/BTC': '', 'XRP/BTC': '', 'NEO/BTC': ''
     })
-    url_mock = PropertyMock(return_value={'test': "api-public.sandbox.gdax.com", 'api': 'https://api.gdax.com'})
+    url_mock = PropertyMock(return_value={'test': "api-public.sandbox.gdax.com",
+                                          'api': 'https://api.gdax.com'})
     type(api_mock).urls = url_mock
     mocker.patch('freqtrade.exchange.Exchange._init_ccxt', MagicMock(return_value=api_mock))
     mocker.patch('freqtrade.exchange.Exchange.validate_timeframes', MagicMock())
@@ -70,6 +72,7 @@ def test_set_sandbox(default_conf, mocker):
     exchange.set_sandbox(exchange._api, default_conf['exchange'], 'Logname')
     assert exchange._api.urls['api'] != liveurl
 
+
 def test_set_sandbox_exception(default_conf, mocker):
     """
     Test Fail scenario
@@ -88,7 +91,6 @@ def test_set_sandbox_exception(default_conf, mocker):
         exchange = Exchange(default_conf)
         default_conf['exchange']['sandbox'] = True
         exchange.set_sandbox(exchange._api, default_conf['exchange'], 'Logname')
-        assert exchange._api.urls.get('test') == False
 
 
 def test_validate_pairs(default_conf, mocker):