pyln-client: to_whole_satoshi returns the rounded up satoshi value

A fractional satoshi value isn't really useful; rounding up loses
precision but that's why you called "whole satoshi", wasn't it?

Changelog-Changed: pyln-client: Millisatoshi has new method, `to_whole_satoshi`; *rounds value up* to the nearest whole satoshi

contrib/pyln-client/pyln/client/lightning.py

@@ -92,6 +92,13 @@ class Millisatoshi:
         """
         return Decimal(self.millisatoshis) / 1000
 
+    def to_whole_satoshi(self) -> int:
+        """
+        Return an int respresenting the number of satoshis;
+        rounded up to the nearest satoshi
+        """
+        return (self.millisatoshis + 999) // 1000
+
     def to_btc(self) -> Decimal:
         """
         Return a Decimal representing the number of bitcoin.

tests/plugins/df_accepter.py

@@ -84,12 +84,12 @@ def on_openchannel(openchannel2, plugin, **kwargs):
     psbt_obj = psbt_from_base64(funding['psbt'])
 
     excess = Millisatoshi(funding['excess_msat'])
-    change_cost = Millisatoshi(124 * feerate // 1000 * 1000)
+    change_cost = Millisatoshi(124 * feerate)
     dust_limit = Millisatoshi(253 * 1000)
     if excess > (dust_limit + change_cost):
         addr = plugin.rpc.newaddr()['bech32']
         change = excess - change_cost
-        output = tx_output_init(int(change.to_satoshi()), get_script(addr))
+        output = tx_output_init(change.to_whole_satoshi(), get_script(addr))
         psbt_add_output_at(psbt_obj, 0, 0, output)
 
     return {'result': 'continue', 'psbt': psbt_to_base64(psbt_obj, 0),