test: coverage for getbalances#total field in wallet_avoidreuse

Author: jonatack

test/functional/wallet_avoidreuse.py

@@ -59,9 +59,11 @@ def assert_unspent(node, total_count=None, total_sum=None, reused_supported=None
 
 def assert_balances(node, mine, margin=0.001):
     '''Make assertions about a node's getbalances output'''
-    got = node.getbalances()["mine"]
+    got, total = node.getbalances()["mine"], 0
     for k,v in mine.items():
         assert_approx(got[k], v, margin)
+        total += v
+    assert_approx(node.getbalances()["total"], total, margin)
 
 class AvoidReuseTest(BitcoinTestFramework):
     def add_options(self, parser):