test: add log setup workaround for tests

freqtrade/loggers/__init__.py

@@ -197,13 +197,16 @@ def setup_logging(config: Config) -> None:
     Process -v/--verbose, --logfile options
     """
     verbosity = config["verbosity"]
-
+    if not config.get("ft_tests_skip_logging"):
         log_config = _create_log_config(config)
-    _set_log_levels(log_config, verbosity, config.get("api_server", {}).get("verbosity", "info"))
+        _set_log_levels(
+            log_config, verbosity, config.get("api_server", {}).get("verbosity", "info")
+        )
 
         logging.config.dictConfig(log_config)
 
     # Add buffer handler to root logger
+    if bufferHandler not in logging.root.handlers:
         logging.root.addHandler(bufferHandler)
 
     # Set color system for console output

tests/conftest.py

@@ -644,6 +644,7 @@ def get_default_conf(testdatadir):
         "trading_mode": "spot",
         "margin_mode": "",
         "candle_type_def": CandleType.SPOT,
+        "ft_tests_skip_logging": True,
     }
     return configuration