* subversion/tests/cmdline/svntest/main.py (wait_on_pipe):
Accept any sequence of bytes even if it is not valid UTF-8 character sequence.
Index: subversion/tests/cmdline/svntest/main.py
===================================================================
--- subversion/tests/cmdline/svntest/main.py	(revision 1877407)
+++ subversion/tests/cmdline/svntest/main.py	(working copy)
@@ -527,10 +527,10 @@
 
   # We always expect STDERR to be strings, not byte-arrays.
   if not isinstance(stderr, str):
-    stderr = stderr.decode("utf-8")
+    stderr = stderr.decode("utf-8", 'surrogateescape')
   if not binary_mode:
     if not isinstance(stdout, str):
-      stdout = stdout.decode("utf-8")
+      stdout = stdout.decode("utf-8", 'surrogateescape')
 
     # Normalize Windows line endings if in text mode.
     if windows: