diff --git a/freqtrade/data/dataprovider.py b/freqtrade/data/dataprovider.py
index 2852cbcb0..b87589df7 100644
--- a/freqtrade/data/dataprovider.py
+++ b/freqtrade/data/dataprovider.py
@@ -17,7 +17,7 @@ from freqtrade.state import RunMode
 logger = logging.getLogger(__name__)
 
 
-class DataProvider(object):
+class DataProvider():
 
     def __init__(self, config: dict, exchange: Exchange) -> None:
         self._config = config
@@ -81,11 +81,14 @@ class DataProvider(object):
         # TODO: Implement me
         pass
 
-    def orderbook(self, pair: str, max: int):
+    def orderbook(self, pair: str, maximum: int):
         """
         return latest orderbook data
+        :param pair: pair to get the data for
+        :param maximum: Maximum number of orderbook entries to query
+        :return: dict including bids/asks with a total of `maximum` entries.
         """
-        return self._exchange.get_order_book(pair, max)
+        return self._exchange.get_order_book(pair, maximum)
 
     @property
     def runmode(self) -> RunMode:
diff --git a/freqtrade/rpc/telegram.py b/freqtrade/rpc/telegram.py
index 3eb060074..fe4929780 100644
--- a/freqtrade/rpc/telegram.py
+++ b/freqtrade/rpc/telegram.py
@@ -217,7 +217,8 @@ class Telegram(RPC):
 
                     "*Open Order:* `{open_order}`" if r['open_order'] else ""
                 ]
-                messages.append("\n".join(filter(None, lines)).format(**r))
+                # Filter empty lines using list-comprehension
+                messages.append("\n".join([l for l in lines if l]).format(**r))
 
             for msg in messages:
                 self._send_msg(msg, bot=bot)
diff --git a/freqtrade/tests/strategy/test_strategy.py b/freqtrade/tests/strategy/test_strategy.py
index 904f84946..9a2c950e5 100644
--- a/freqtrade/tests/strategy/test_strategy.py
+++ b/freqtrade/tests/strategy/test_strategy.py
@@ -69,8 +69,8 @@ def test_load_strategy(result):
 
 
 def test_load_strategy_base64(result):
-    with open("freqtrade/tests/strategy/test_strategy.py", "r") as file:
-        encoded_string = urlsafe_b64encode(file.read().encode("utf-8")).decode("utf-8")
+    with open("freqtrade/tests/strategy/test_strategy.py", "rb") as file:
+        encoded_string = urlsafe_b64encode(file.read()).decode("utf-8")
     resolver = StrategyResolver({'strategy': 'TestStrategy:{}'.format(encoded_string)})
     assert 'adx' in resolver.strategy.advise_indicators(result, {'pair': 'ETH/BTC'})
 
diff --git a/freqtrade/tests/test_freqtradebot.py b/freqtrade/tests/test_freqtradebot.py
index 89d3bba5f..9a22a4f94 100644
--- a/freqtrade/tests/test_freqtradebot.py
+++ b/freqtrade/tests/test_freqtradebot.py
@@ -2,7 +2,6 @@
 # pragma pylint: disable=protected-access, too-many-lines, invalid-name, too-many-arguments
 
 import logging
-import re
 import time
 from copy import deepcopy
 from unittest.mock import MagicMock, PropertyMock
@@ -1419,8 +1418,7 @@ def test_update_trade_state(mocker, default_conf, limit_buy_order, caplog) -> No
     # Assert we call handle_trade() if trade is feasible for execution
     freqtrade.update_trade_state(trade)
 
-    regexp = re.compile('Found open order for.*')
-    assert filter(regexp.match, caplog.record_tuples)
+    assert log_has_re('Found open order for.*', caplog.record_tuples)
 
 
 def test_update_trade_state_withorderdict(default_conf, trades_for_order, limit_buy_order, mocker):
@@ -1941,14 +1939,11 @@ def test_check_handle_timedout_exception(default_conf, ticker, mocker, caplog) -
     )
 
     Trade.session.add(trade_buy)
-    regexp = re.compile(
-        'Cannot query order for Trade(id=1, pair=ETH/BTC, amount=90.99181073, '
-        'open_rate=0.00001099, open_since=10 hours ago) due to Traceback (most '
-        'recent call last):\n.*'
-    )
 
     freqtrade.check_handle_timedout()
-    assert filter(regexp.match, caplog.record_tuples)
+    assert log_has_re(r'Cannot query order for Trade\(id=1, pair=ETH/BTC, amount=90.99181073, '
+                      r'open_rate=0.00001099, open_since=10 hours ago\) due to Traceback \(most '
+                      r'recent call last\):\n.*', caplog.record_tuples)
 
 
 def test_handle_timedout_limit_buy(mocker, default_conf) -> None:
diff --git a/freqtrade/tests/test_plotting.py b/freqtrade/tests/test_plotting.py
index cef229d19..565659d25 100644
--- a/freqtrade/tests/test_plotting.py
+++ b/freqtrade/tests/test_plotting.py
@@ -23,7 +23,7 @@ def fig_generating_mock(fig, *args, **kwargs):
 
 
 def find_trace_in_fig_data(data, search_string: str):
-    matches = filter(lambda x: x.name == search_string, data)
+    matches = (d for d in data if d.name == search_string)
     return next(matches)
 
 
diff --git a/freqtrade/tests/test_talib.py b/freqtrade/tests/test_talib.py
index 093c3023c..2c7f73eb1 100644
--- a/freqtrade/tests/test_talib.py
+++ b/freqtrade/tests/test_talib.py
@@ -13,4 +13,4 @@ def test_talib_bollingerbands_near_zero_values():
         {'close': 0.00000014}
     ])
     bollinger = ta.BBANDS(inputs, matype=0, timeperiod=2)
-    assert (bollinger['upperband'][3] != bollinger['middleband'][3])
+    assert bollinger['upperband'][3] != bollinger['middleband'][3]