litcli: handle 0 asset units case on sendpayment results

Author: GeorgeTsagk

cmd/litcli/ln.go

@@ -216,6 +216,13 @@ func (w *resultStreamWrapper) Recv() (*lnrpc.Payment, error) {
 		amountMsat := lnwire.MilliSatoshi(w.amountMsat)
 		milliSatsFP := rfqmath.MilliSatoshiToUnits(amountMsat, *rate)
 		numUnits := milliSatsFP.ScaleTo(0).ToUint64()
+		if numUnits == 0 {
+			return nil, fmt.Errorf("asset rate %v not sufficient "+
+				"to represent value of %v",
+				rate.ToUint64(), amountMsat,
+			)
+		}
+
 		msatPerUnit := uint64(w.amountMsat) / numUnits
 
 		fmt.Printf("Got quote for %v asset units at %v msat/unit from "+