From 7108a2e57d557b4fc2580ec0defb2693c7e96164 Mon Sep 17 00:00:00 2001
From: Matthias <xmatthias@outlook.com>
Date: Sun, 9 Jun 2019 14:05:36 +0200
Subject: [PATCH] Add deep_merge for _ft_has and test

---
 freqtrade/exchange/exchange.py            | 31 +++++++++++++++--------
 freqtrade/tests/exchange/test_exchange.py | 27 ++++++++++++++++++++
 2 files changed, 47 insertions(+), 11 deletions(-)

diff --git a/freqtrade/exchange/exchange.py b/freqtrade/exchange/exchange.py
index 72a0efb1f..07a5e9037 100644
--- a/freqtrade/exchange/exchange.py
+++ b/freqtrade/exchange/exchange.py
@@ -2,23 +2,24 @@
 """
 Cryptocurrency Exchanges support
 """
-import logging
+import asyncio
 import inspect
-from random import randint
-from typing import List, Dict, Tuple, Any, Optional
+import logging
+from copy import deepcopy
 from datetime import datetime
-from math import floor, ceil
+from math import ceil, floor
+from random import randint
+from typing import Any, Dict, List, Optional, Tuple
 
 import arrow
-import asyncio
 import ccxt
 import ccxt.async_support as ccxt_async
 from pandas import DataFrame
 
-from freqtrade import (constants, DependencyException, OperationalException,
-                       TemporaryError, InvalidOrderException)
+from freqtrade import (DependencyException, InvalidOrderException,
+                       OperationalException, TemporaryError, constants)
 from freqtrade.data.converter import parse_ticker_dataframe
-
+from freqtrade.misc import deep_merge_dicts
 
 logger = logging.getLogger(__name__)
 
@@ -68,12 +69,13 @@ class Exchange(object):
     _params: Dict = {}
 
     # Dict to specify which options each exchange implements
-    # TODO: this should be merged with attributes from subclasses
-    # To avoid having to copy/paste this to all subclasses.
-    _ft_has: Dict = {
+    # This defines defaults, which can be selectively overridden by subclasses using _ft_has
+    # or by specifying them in the configuration.
+    _ft_has_default: Dict = {
         "stoploss_on_exchange": False,
         "order_time_in_force": ["gtc"],
     }
+    _ft_has: Dict = {}
 
     def __init__(self, config: dict) -> None:
         """
@@ -100,6 +102,13 @@ class Exchange(object):
             logger.info('Instance is running with dry_run enabled')
 
         exchange_config = config['exchange']
+
+        # Deep merge ft_has with default ft_has options
+        self._ft_has = deep_merge_dicts(self._ft_has, deepcopy(self._ft_has_default))
+        if exchange_config.get("_ft_has_params"):
+            self._ft_has = deep_merge_dicts(exchange_config.get("_ft_has_params"),
+                                            self._ft_has)
+
         self._api: ccxt.Exchange = self._init_ccxt(
             exchange_config, ccxt_kwargs=exchange_config.get('ccxt_config'))
         self._api_async: ccxt_async.Exchange = self._init_ccxt(
diff --git a/freqtrade/tests/exchange/test_exchange.py b/freqtrade/tests/exchange/test_exchange.py
index fda9c8241..f0dc96626 100644
--- a/freqtrade/tests/exchange/test_exchange.py
+++ b/freqtrade/tests/exchange/test_exchange.py
@@ -1435,3 +1435,30 @@ def test_stoploss_limit_order_dry_run(default_conf, mocker):
     assert order['type'] == order_type
     assert order['price'] == 220
     assert order['amount'] == 1
+
+
+def test_merge_ft_has_dict(default_conf, mocker):
+    mocker.patch('freqtrade.exchange.Exchange._init_ccxt', MagicMock(return_value=MagicMock()))
+    mocker.patch('freqtrade.exchange.Exchange._load_async_markets', MagicMock())
+    mocker.patch('freqtrade.exchange.Exchange.validate_pairs', MagicMock())
+    mocker.patch('freqtrade.exchange.Exchange.validate_timeframes', MagicMock())
+    ex = Exchange(default_conf)
+    assert ex._ft_has == Exchange._ft_has_default
+
+    ex = Kraken(default_conf)
+    assert ex._ft_has == Exchange._ft_has_default
+
+    # Binance defines different values
+    ex = Binance(default_conf)
+    assert ex._ft_has != Exchange._ft_has_default
+    assert ex._ft_has['stoploss_on_exchange']
+    assert ex._ft_has['order_time_in_force'] == ['gtc', 'fok', 'ioc']
+
+    conf = copy.deepcopy(default_conf)
+    conf['exchange']['_ft_has_params'] = {"DeadBeef": 20,
+                                          "stoploss_on_exchange": False}
+    # Use settings from configuration (overriding stoploss_on_exchange)
+    ex = Binance(conf)
+    assert ex._ft_has != Exchange._ft_has_default
+    assert not ex._ft_has['stoploss_on_exchange']
+    assert ex._ft_has['DeadBeef'] == 20