diff --git a/freqtrade/exchange/exchange.py b/freqtrade/exchange/exchange.py
index 04ad10a68..c4ed75878 100644
--- a/freqtrade/exchange/exchange.py
+++ b/freqtrade/exchange/exchange.py
@@ -258,8 +258,8 @@ class Exchange:
                 api.urls['api'] = api.urls['test']
                 logger.info("Enabled Sandbox API on %s", name)
             else:
-                logger.warning(name, "No Sandbox URL in CCXT, exiting. "
-                                     "Please check your config.json")
+                logger.warning(
+                    f"No Sandbox URL in CCXT for {name}, exiting. Please check your config.json")
                 raise OperationalException(f'Exchange {name} does not provide a sandbox api')
 
     def _load_async_markets(self, reload: bool = False) -> None:
diff --git a/requirements-dev.txt b/requirements-dev.txt
index 9f9be638d..c02a439d3 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -8,7 +8,7 @@ flake8==3.8.3
 flake8-type-annotations==0.1.0
 flake8-tidy-imports==4.1.0
 mypy==0.782
-pytest==5.4.3
+pytest==6.0.1
 pytest-asyncio==0.14.0
 pytest-cov==2.10.0
 pytest-mock==3.2.0
diff --git a/tests/test_freqtradebot.py b/tests/test_freqtradebot.py
index fd57eae6f..dcddf34e3 100644
--- a/tests/test_freqtradebot.py
+++ b/tests/test_freqtradebot.py
@@ -1726,6 +1726,7 @@ def test_update_trade_state_withorderdict(default_conf, trades_for_order, limit_
         amount=amount,
         exchange='binance',
         open_rate=0.245441,
+        open_date=arrow.utcnow().datetime,
         fee_open=fee.return_value,
         fee_close=fee.return_value,
         open_order_id="123456",
@@ -1816,6 +1817,7 @@ def test_update_trade_state_sell(default_conf, trades_for_order, limit_sell_orde
         open_rate=0.245441,
         fee_open=0.0025,
         fee_close=0.0025,
+        open_date=arrow.utcnow().datetime,
         open_order_id="123456",
         is_open=True,
     )