manage None or string value returned by custom_entry_price and add unit test for those cases

freqtrade/freqtradebot.py

@@ -479,13 +479,17 @@ class FreqtradeBot(LoggingMixin):
             buy_limit_requested = price
         else:
             # Calculate price
-            buy_limit_requested = self.exchange.get_rate(pair, refresh=True, side="buy")
+            proposed_buy_rate = self.exchange.get_rate(pair, refresh=True, side="buy")
             custom_entry_price = strategy_safe_wrapper(self.strategy.custom_entry_price,
-                                                       default_retval=buy_limit_requested)(
+                                                       default_retval=proposed_buy_rate)(
                 pair=pair, current_time=datetime.now(timezone.utc),
-                proposed_rate=buy_limit_requested)
+                proposed_rate=proposed_buy_rate)
 
-            buy_limit_requested = custom_entry_price
+            if custom_entry_price and (isinstance(custom_entry_price, int)
+                                       or isinstance(custom_entry_price, float)):
+                buy_limit_requested = custom_entry_price
+            else:
+                buy_limit_requested = proposed_buy_rate
 
         if not buy_limit_requested:
             raise PricingError('Could not determine buy price.')

tests/test_freqtradebot.py

@@ -913,6 +913,30 @@ def test_execute_buy(mocker, default_conf, fee, limit_buy_order, limit_buy_order
     assert trade
     assert trade.open_rate_requested == 0.77
 
+    # In case of custom entry price set to None
+    limit_buy_order['status'] = 'open'
+    limit_buy_order['id'] = '5567'
+    freqtrade.strategy.custom_entry_price = lambda **kwargs: None
+
+    mocker.patch.multiple(
+        'freqtrade.exchange.Exchange',
+        get_rate=MagicMock(return_value=10),
+    )
+
+    assert freqtrade.execute_buy(pair, stake_amount)
+    trade = Trade.query.all()[7]
+    assert trade
+    assert trade.open_rate_requested == 10
+
+    # In case of custom entry price not float type
+    limit_buy_order['status'] = 'open'
+    limit_buy_order['id'] = '5568'
+    freqtrade.strategy.custom_entry_price = lambda **kwargs: "string price"
+    assert freqtrade.execute_buy(pair, stake_amount)
+    trade = Trade.query.all()[8]
+    assert trade
+    assert trade.open_rate_requested == 10
+
 
 def test_execute_buy_confirm_error(mocker, default_conf, fee, limit_buy_order) -> None:
     freqtrade = get_patched_freqtradebot(mocker, default_conf)