Ensure one test can't fail 20 others

tests/rpc/test_rpc_apiserver.py

@@ -21,6 +21,7 @@ from freqtrade.__init__ import __version__
 from freqtrade.enums import CandleType, RunMode, State, TradingMode
 from freqtrade.exceptions import DependencyException, ExchangeError, OperationalException
 from freqtrade.loggers import setup_logging, setup_logging_pre
+from freqtrade.optimize.backtesting import Backtesting
 from freqtrade.persistence import PairLocks, Trade
 from freqtrade.rpc import RPC
 from freqtrade.rpc.api_server import ApiServer
@@ -1666,6 +1667,7 @@ def test_sysinfo(botclient):
 
 
 def test_api_backtesting(botclient, mocker, fee, caplog, tmpdir):
+    try:
         ftbot, client = botclient
         mocker.patch(f'{EXMS}.get_fee', fee)
 
@@ -1797,6 +1799,8 @@ def test_api_backtesting(botclient, mocker, fee, caplog, tmpdir):
         data['strategy'] = "xx:cHJpbnQoImhlbGxvIHdvcmxkIik="
         rc = client_post(client, f"{BASE_URI}/backtest", data=data)
         assert_response(rc, 500)
+    finally:
+        Backtesting.cleanup()
 
 
 def test_api_backtest_history(botclient, mocker, testdatadir):