diff --git a/test/functional/combine_logs.py b/test/functional/combine_logs.py
--- a/test/functional/combine_logs.py
+++ b/test/functional/combine_logs.py
@@ -8,7 +8,6 @@
 
 import argparse
 from collections import defaultdict, namedtuple
-import glob
 import heapq
 import itertools
 import os
@@ -86,13 +85,14 @@
     for each of the input log files."""
 
     # Find out what the folder is called that holds the debug.log file
-    chain = glob.glob("{}/node0/*/debug.log".format(tmp_dir))
-    if chain:
-        # pick the first one if more than one chain was found (should never
-        # happen)
-        chain = chain[0]
+    glob = pathlib.Path(tmp_dir).glob('node0/**/debug.log')
+    path = next(glob, None)
+    if path:
+        # more than one debug.log should never happen
+        assert next(glob, None) is None
         # extract the chain name
-        chain = re.search(r'node0/(.+?)/debug\.log$', chain).group(1)
+        chain = re.search(r'node0/(.+?)/debug\.log$',
+                          path.as_posix()).group(1)
     else:
         # fallback to regtest (should only happen when none exists)
         chain = 'regtest'