From 65ab8e812066b86fdf9e1ce8b7f1b88f24c19092 Mon Sep 17 00:00:00 2001
From: callebtc <93376500+callebtc@users.noreply.github.com>
Date: Fri, 23 Jun 2023 20:37:21 +0200
Subject: [PATCH] fee reserves cant be negative (#260)

---
 cashu/core/helpers.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cashu/core/helpers.py b/cashu/core/helpers.py
index 58a5d0a..b5e590e 100644
--- a/cashu/core/helpers.py
+++ b/cashu/core/helpers.py
@@ -51,5 +51,5 @@ def calculate_number_of_blank_outputs(fee_reserve_sat: int):
     The formula ensures that any overpaid fees can be represented by the blank outputs,
     see NUT-08 for details.
     """
-    assert fee_reserve_sat > 0, "Fee reserve has to be positive."
+    assert fee_reserve_sat >= 0, "Fee reserve can't be negative."
     return max(math.ceil(math.log2(fee_reserve_sat)), 1)