[qa] util: Move check_fee_amount out of wallet.py

qa/rpc-tests/test_framework/util.py

@@ -477,6 +477,15 @@ def random_transaction(nodes, amount, min_fee, fee_increment, fee_variants):
 
     return (txid, signresult["hex"], fee)
 
+def assert_fee_amount(fee, tx_size, fee_per_kB):
+    """Assert the fee was in range"""
+    target_fee = tx_size * fee_per_kB / 1000
+    if fee < target_fee:
+        raise AssertionError("Fee of %s BTC too low! (Should be %s BTC)"%(str(fee), str(target_fee)))
+    # allow the wallet's estimation to be at most 2 bytes off
+    if fee > (tx_size + 2) * fee_per_kB / 1000:
+        raise AssertionError("Fee of %s BTC too high! (Should be %s BTC)"%(str(fee), str(target_fee)))
+
 def assert_equal(thing1, thing2):
     if thing1 != thing2:
         raise AssertionError("%s != %s"%(str(thing1),str(thing2)))

qa/rpc-tests/wallet.py

@@ -11,12 +11,7 @@ class WalletTest (BitcoinTestFramework):
     def check_fee_amount(self, curr_balance, balance_with_fee, fee_per_byte, tx_size):
         """Return curr_balance after asserting the fee was in range"""
         fee = balance_with_fee - curr_balance
-        target_fee = fee_per_byte * tx_size
+        assert_fee_amount(fee, tx_size, fee_per_byte * 1000)
-        if fee < target_fee:
-            raise AssertionError("Fee of %s BTC too low! (Should be %s BTC)"%(str(fee), str(target_fee)))
-        # allow the node's estimation to be at most 2 bytes off
-        if fee > fee_per_byte * (tx_size + 2):
-            raise AssertionError("Fee of %s BTC too high! (Should be %s BTC)"%(str(fee), str(target_fee)))
         return curr_balance
 
     def __init__(self):