Check if number_assets is defined, as it's required by VolumePairList

docs/developer.md

@@ -43,7 +43,7 @@ Additional elements can be configured as needed. `VolumePairList` uses `"sort_ke
 #### short_desc
 
 Returns a description used for Telegram messages.
-This should coutain the name of the Provider, as well as a short description containing the number of assets. Please follow the format `"PairlistName - top/bottom X pairs"`.
+This should contain the name of the Provider, as well as a short description containing the number of assets. Please follow the format `"PairlistName - top/bottom X pairs"`.
 
 #### refresh_pairlist
 

freqtrade/pairlist/VolumePairList.py

@@ -20,6 +20,10 @@ class VolumePairList(IPairList):
     def __init__(self, freqtrade, config: dict) -> None:
         super().__init__(freqtrade, config)
         self._whitelistconf = self._config.get('pairlist', {}).get('config')
+        if 'number_assets' not in self._whitelistconf:
+            raise OperationalException(
+                f'`number_assets` not specified. Please check your configuration '
+                'for "pairlist.config.number_assets"')
         self._number_pairs = self._whitelistconf['number_assets']
         self._sort_key = self._whitelistconf.get('sort_key', 'quoteVolume')
 

freqtrade/tests/pairlist/test_pairlist.py

@@ -85,6 +85,14 @@ def test_refresh_pairlist_dynamic(mocker, markets, tickers, whitelist_conf):
 
     assert whitelist == freqtradebot.pairlists.whitelist
 
+    whitelist_conf['pairlist'] = {'method': 'VolumePairList',
+                                  'config': {}
+                                  }
+    with pytest.raises(OperationalException,
+                       match=r'`number_assets` not specified. Please check your configuration '
+                             r'for "pairlist.config.number_assets"'):
+        PairListResolver('VolumePairList', freqtradebot, whitelist_conf).pairlist
+
 
 def test_VolumePairList_refresh_empty(mocker, markets_empty, whitelist_conf):
     freqtradebot = get_patched_freqtradebot(mocker, whitelist_conf)