Implement strategy-controlled stake sizes. Expose self.wallet to a strategy.

tests/rpc/test_rpc.py

@@ -886,7 +886,7 @@ def test_rpcforcebuy(mocker, default_conf, ticker, fee, limit_buy_order_open) ->
 
     # Test not buying
     freqtradebot = get_patched_freqtradebot(mocker, default_conf)
-    freqtradebot.config['stake_amount'] = 0.0000001
+    freqtradebot.config['stake_amount'] = 0
     patch_get_signal(freqtradebot, (True, False))
     rpc = RPC(freqtradebot)
     pair = 'TKN/BTC'

tests/test_freqtradebot.py

@@ -413,6 +413,26 @@ def test_create_trade_too_small_stake_amount(default_conf, ticker, limit_buy_ord
 
     patch_get_signal(freqtrade)
 
+    assert freqtrade.create_trade('ETH/BTC')
+
+
+def test_create_trade_zero_stake_amount(default_conf, ticker, limit_buy_order_open,
+                                        fee, mocker) -> None:
+    patch_RPCManager(mocker)
+    patch_exchange(mocker)
+    buy_mock = MagicMock(return_value=limit_buy_order_open)
+    mocker.patch.multiple(
+        'freqtrade.exchange.Exchange',
+        fetch_ticker=ticker,
+        buy=buy_mock,
+        get_fee=fee,
+    )
+
+    freqtrade = FreqtradeBot(default_conf)
+    freqtrade.config['stake_amount'] = 0
+
+    patch_get_signal(freqtrade)
+
     assert not freqtrade.create_trade('ETH/BTC')