From 265d7c44b1aae06aee93f745a865807732218a73 Mon Sep 17 00:00:00 2001
From: John Newbery <john@johnnewbery.com>
Date: Wed, 13 Dec 2017 14:39:44 -0500
Subject: [PATCH] [tests] Improve assert message when wait_until() fails

---
 test/functional/test_framework/util.py | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/test/functional/test_framework/util.py b/test/functional/test_framework/util.py
index 7be695550b..e676805f3d 100644
--- a/test/functional/test_framework/util.py
+++ b/test/functional/test_framework/util.py
@@ -8,6 +8,7 @@ from base64 import b64encode
 from binascii import hexlify, unhexlify
 from decimal import Decimal, ROUND_DOWN
 import hashlib
+import inspect
 import json
 import logging
 import os
@@ -204,9 +205,9 @@ def wait_until(predicate, *, attempts=float('inf'), timeout=float('inf'), lock=N
     if attempts == float('inf') and timeout == float('inf'):
         timeout = 60
     attempt = 0
-    timeout += time.time()
+    time_end = time.time() + timeout
 
-    while attempt < attempts and time.time() < timeout:
+    while attempt < attempts and time.time() < time_end:
         if lock:
             with lock:
                 if predicate():
@@ -218,8 +219,12 @@ def wait_until(predicate, *, attempts=float('inf'), timeout=float('inf'), lock=N
         time.sleep(0.05)
 
     # Print the cause of the timeout
-    assert_greater_than(attempts, attempt)
-    assert_greater_than(timeout, time.time())
+    predicate_source = inspect.getsourcelines(predicate)
+    logger.error("wait_until() failed. Predicate: {}".format(predicate_source))
+    if attempt >= attempts:
+        raise AssertionError("Predicate {} not true after {} attempts".format(predicate_source, attempts))
+    elif time.time() >= time_end:
+        raise AssertionError("Predicate {} not true after {} seconds".format(predicate_source, timeout))
     raise RuntimeError('Unreachable')
 
 # RPC/P2P connection constants and functions