From f3b42b0ef330db41a3d83ff053ff484d1f3b9ba2 Mon Sep 17 00:00:00 2001
From: Sam Germain <sam.germain@usask.ca>
Date: Sat, 29 Jan 2022 03:22:08 -0600
Subject: [PATCH] wrote exchange.get_max_amount_tradable

---
 freqtrade/exchange/exchange.py  |  14 +++
 tests/exchange/test_exchange.py | 147 ++++++++++++++++++++++++++++++++
 2 files changed, 161 insertions(+)

diff --git a/freqtrade/exchange/exchange.py b/freqtrade/exchange/exchange.py
index 2b35417d3..99a903f26 100644
--- a/freqtrade/exchange/exchange.py
+++ b/freqtrade/exchange/exchange.py
@@ -2119,6 +2119,20 @@ class Exchange:
             raise OperationalException(
                 "Freqtrade only supports isolated futures for leverage trading")
 
+    def get_max_amount_tradable(self, pair: str) -> float:
+        '''
+        Gets the maximum amount of a currency that the exchange will let you trade
+        '''
+        market = self.markets[pair]
+        contractSize = market['contractSize']
+        if not contractSize or market['spot']:
+            contractSize = 1
+        maxAmount = market['limits']['amount']['max']
+        if maxAmount:
+            return maxAmount * contractSize
+        else:
+            return float('inf')
+
 
 def is_exchange_known_ccxt(exchange_name: str, ccxt_module: CcxtModuleType = None) -> bool:
     return exchange_name in ccxt_exchanges(ccxt_module)
diff --git a/tests/exchange/test_exchange.py b/tests/exchange/test_exchange.py
index ae94ae102..14a6661d1 100644
--- a/tests/exchange/test_exchange.py
+++ b/tests/exchange/test_exchange.py
@@ -4042,3 +4042,150 @@ def test_liquidation_price(
         upnl_ex_1=upnl_ex_1,
         position=position,
     ), 2), expected)
+
+
+def test_get_max_amount_tradable(
+    mocker,
+    default_conf,
+):
+    api_mock = MagicMock()
+    exchange = get_patched_exchange(mocker, default_conf, api_mock)
+    markets = {
+        'XRP/USDT': {
+            'limits': {
+                'leverage': {
+                    'min': None,
+                    'max': None,
+                },
+                'amount': {
+                    'min': 0.001,
+                    'max': 10000
+                },
+                'price': {
+                    'min': 39.86,
+                    'max': 306177
+                },
+                'cost': {
+                    'min': 5,
+                    'max': None
+                },
+                'market': {
+                    'min': 0.001,
+                    'max': 2000
+                },
+            },
+            'precision': {
+                'price': 2,
+                'amount': 3,
+                'base': 8,
+                'quote': 8
+            },
+            'contractSize': None,
+            'spot': False,
+            'swap': True
+        },
+        'LTC/USDT': {
+            'limits': {
+                'leverage': {
+                    'min': None,
+                    'max': None,
+                },
+                'amount': {
+                    'min': 0.001,
+                    'max': None
+                },
+                'price': {
+                    'min': 39.86,
+                    'max': 306177
+                },
+                'cost': {
+                    'min': 5,
+                    'max': None
+                },
+                'market': {
+                    'min': 0.001,
+                    'max': 2000
+                },
+            },
+            'precision': {
+                'price': 2,
+                'amount': 3,
+                'base': 8,
+                'quote': 8
+            },
+            'contractSize': 0.01,
+            'spot': False,
+            'swap': True
+        },
+        'ETH/USDT': {
+            'limits': {
+                'leverage': {
+                    'min': None,
+                    'max': None,
+                },
+                'amount': {
+                    'min': 0.001,
+                    'max': 10000
+                },
+                'price': {
+                    'min': 39.86,
+                    'max': 306177
+                },
+                'cost': {
+                    'min': 5,
+                    'max': None
+                },
+                'market': {
+                    'min': 0.001,
+                    'max': 2000
+                },
+            },
+            'precision': {
+                'price': 2,
+                'amount': 3,
+                'base': 8,
+                'quote': 8
+            },
+            'contractSize': 0.01,
+            'spot': False,
+            'swap': True
+        },
+        'BTC/USDT': {
+            'limits': {
+                'leverage': {
+                    'min': None,
+                    'max': None,
+                },
+                'amount': {
+                    'min': 0.001,
+                    'max': 10000
+                },
+                'price': {
+                    'min': 39.86,
+                    'max': 306177
+                },
+                'cost': {
+                    'min': 5,
+                    'max': None
+                },
+                'market': {
+                    'min': 0.001,
+                    'max': 2000
+                },
+            },
+            'precision': {
+                'price': 2,
+                'amount': 3,
+                'base': 8,
+                'quote': 8
+            },
+            'contractSize': 0.01,
+            'spot': True,
+            'swap': False
+        }
+    }
+    mocker.patch('freqtrade.exchange.Exchange.markets', markets)
+    assert exchange.get_max_amount_tradable('XRP/USDT') == 10000
+    assert exchange.get_max_amount_tradable('LTC/USDT') == float('inf')
+    assert exchange.get_max_amount_tradable('ETH/USDT') == 100
+    assert exchange.get_max_amount_tradable('BTC/USDT') == 10000