Add explicit test and document behavior

freqtrade/exchange/exchange.py

@@ -630,7 +630,8 @@ class Exchange:
             if required_candle_call_count > 5:
                 # Only allow 5 calls per pair to somewhat limit the impact
                 raise OperationalException(
-                    f"This strategy requires {startup_candles} candles to start, which is more than 5x "
+                    f"This strategy requires {startup_candles} candles to start, "
+                    "which is more than 5x "
                     f"the amount of candles {self.name} provides for {timeframe}.")
         elif required_candle_call_count > 1:
             raise OperationalException(

freqtrade/exchange/okx.py

@@ -41,11 +41,13 @@ class Okx(Exchange):
     net_only = True
 
     def ohlcv_candle_limit(
-                self, timeframe: str, candle_type: CandleType, since_ms: Optional[int] = None) -> int:
+            self, timeframe: str, candle_type: CandleType, since_ms: Optional[int] = None) -> int:
         """
         Exchange ohlcv candle limit
-        Uses ohlcv_candle_limit_per_timeframe if the exchange has different limits
-        per timeframe (e.g. bittrex), otherwise falls back to ohlcv_candle_limit
+        OKX has the following behaviour:
+        * 300 candles for uptodate data
+        * 100 candles for historic data
+        * 100 candles for additional candles (not futures or spot).
         :param timeframe: Timeframe to check
         :param candle_type: Candle-type
         :param since_ms: Candle-type

tests/exchange/test_okx.py

@@ -1,12 +1,39 @@
+from datetime import datetime, timedelta, timezone
 from unittest.mock import MagicMock, PropertyMock
 
 import pytest
 
 from freqtrade.enums import MarginMode, TradingMode
+from freqtrade.enums.candletype import CandleType
+from freqtrade.exchange.exchange import timeframe_to_minutes
 from tests.conftest import get_patched_exchange
 from tests.exchange.test_exchange import ccxt_exceptionhandlers
 
 
+def test_okx_ohlcv_candle_limit(default_conf, mocker):
+    exchange = get_patched_exchange(mocker, default_conf, id='okx')
+    timeframes = ('1m', '5m', '1h')
+    start_time = int(datetime(2021, 1, 1, tzinfo=timezone.utc).timestamp() * 1000)
+
+    for timeframe in timeframes:
+        assert exchange.ohlcv_candle_limit(timeframe, CandleType.SPOT) == 300
+        assert exchange.ohlcv_candle_limit(timeframe, CandleType.FUTURES) == 300
+        assert exchange.ohlcv_candle_limit(timeframe, CandleType.MARK) == 100
+        assert exchange.ohlcv_candle_limit(timeframe, CandleType.FUNDING_RATE) == 100
+        assert exchange.ohlcv_candle_limit(timeframe, CandleType.SPOT, start_time) == 100
+        assert exchange.ohlcv_candle_limit(timeframe, CandleType.FUTURES, start_time) == 100
+        assert exchange.ohlcv_candle_limit(timeframe, CandleType.MARK, start_time) == 100
+        assert exchange.ohlcv_candle_limit(timeframe, CandleType.FUNDING_RATE, start_time) == 100
+        one_call = int((datetime.now(timezone.utc) - timedelta(
+            minutes=290 * timeframe_to_minutes(timeframe))).timestamp() * 1000)
+        assert exchange.ohlcv_candle_limit(timeframe, CandleType.SPOT, one_call) == 300
+        assert exchange.ohlcv_candle_limit(timeframe, CandleType.FUTURES, one_call) == 300
+        one_call = int((datetime.now(timezone.utc) - timedelta(
+            minutes=320 * timeframe_to_minutes(timeframe))).timestamp() * 1000)
+        assert exchange.ohlcv_candle_limit(timeframe, CandleType.SPOT, one_call) == 100
+        assert exchange.ohlcv_candle_limit(timeframe, CandleType.FUTURES, one_call) == 100
+
+
 def test_get_maintenance_ratio_and_amt_okx(
     default_conf,
     mocker,