Remove Strategy fallback to default strategy (#490)

* Remove Strategy fallback to default strategy

docs/bot-usage.md

@@ -32,7 +32,7 @@ optional arguments:
   --dry-run-db          Force dry run to use a local DB
                         "tradesv3.dry_run.sqlite" instead of memory DB. Work
                         only if dry_run is enabled.
-  -dd PATH, --datadir PATH
+  --datadir PATH
                         path to backtest data (default freqdata/tests/testdata
   --dynamic-whitelist [INT]
                         dynamically generate and update whitelist based on 24h
@@ -65,8 +65,8 @@ load it:
 python3 ./freqtrade/main.py --strategy my_awesome_strategy
 ```
 
-If the bot does not find your strategy file, it will fallback to the 
+If the bot does not find your strategy file, it will display in an error
-`default_strategy`.
+ message the reason (File not found, or errors in your code).
 
 Learn more about strategy file in [optimize your bot](https://github.com/gcarq/freqtrade/blob/develop/docs/bot-optimization.md).
 

freqtrade/misc.py

@@ -163,7 +163,7 @@ def common_args_parser(description: str):
         '-s', '--strategy',
         help='specify strategy file (default: freqtrade/strategy/default_strategy.py)',
         dest='strategy',
-        default='.default_strategy',
+        default='default_strategy',
         type=str,
         metavar='PATH',
     )

freqtrade/strategy/strategy.py

@@ -95,8 +95,16 @@ class Strategy(object):
             self.custom_strategy = self._load_class(path + strategy_name)
 
         # Fallback to the default strategy
-        except (ImportError, TypeError):
+        except (ImportError, TypeError) as error:
-            self.custom_strategy = self._load_class('.' + self.DEFAULT_STRATEGY)
+            self.logger.error(
+                "Impossible to load Strategy 'user_data/strategies/%s.py'. This file does not exist"
+                " or contains Python code errors",
+                strategy_name
+            )
+            self.logger.error(
+                "The error is:\n%s.",
+                error
+            )
 
     def _load_class(self, filename: str) -> IStrategy:
         """

freqtrade/tests/strategy/test_strategy.py

@@ -32,7 +32,7 @@ def test_load_strategy(result):
     strategy.logger = logging.getLogger(__name__)
 
     assert not hasattr(Strategy, 'custom_strategy')
-    strategy._load_strategy('default_strategy')
+    strategy._load_strategy('test_strategy')
 
     assert not hasattr(Strategy, 'custom_strategy')
 
@@ -40,6 +40,18 @@ def test_load_strategy(result):
     assert 'adx' in strategy.populate_indicators(result)
 
 
+def test_load_not_found_strategy(caplog):
+    strategy = Strategy()
+    strategy.logger = logging.getLogger(__name__)
+
+    assert not hasattr(Strategy, 'custom_strategy')
+    strategy._load_strategy('NotFoundStrategy')
+
+    error_msg = "Impossible to load Strategy 'user_data/strategies/{}.py'. This file does not " \
+                "exist or contains Python code errors".format('NotFoundStrategy')
+    assert ('test_strategy', logging.ERROR, error_msg) in caplog.record_tuples
+
+
 def test_strategy(result):
     strategy = Strategy()
     strategy.init({'strategy': 'default_strategy'})