Minor fix in amount_to_precision logic

freqtrade/exchange/exchange.py

@@ -2855,8 +2855,10 @@ def amount_to_precision(amount: float, amount_precision: Optional[float],
     :return: truncated amount
     """
     if amount_precision is not None and precisionMode is not None:
+        precision = int(amount_precision) if precisionMode != TICK_SIZE else amount_precision
+        # precision must be an int for non-ticksize inputs.
         amount = float(decimal_to_precision(amount, rounding_mode=TRUNCATE,
-                                            precision=amount_precision,
+                                            precision=precision,
                                             counting_mode=precisionMode,
                                             ))
 

tests/rpc/test_rpc.py

@@ -761,7 +761,7 @@ def test_rpc_force_exit(default_conf, ticker, fee, mocker) -> None:
     # and trade amount is updated
     rpc._rpc_force_exit('3')
     assert cancel_order_mock.call_count == 1
-    assert trade.amount == filled_amount
+    assert pytest.approx(trade.amount) == filled_amount
 
     mocker.patch(
         'freqtrade.exchange.Exchange.fetch_order',