diff --git a/tests/test-largefiles-small-disk.t b/tests/test-largefiles-small-disk.t
--- a/tests/test-largefiles-small-disk.t
+++ b/tests/test-largefiles-small-disk.t
@@ -11,7 +11,7 @@
   > _origcopyfileobj = shutil.copyfileobj
   > def copyfileobj(fsrc, fdst, length=16*1024):
   >     # allow journal files (used by transaction) to be written
-  >     if 'journal.' in fdst.name:
+  >     if b'journal.' in fdst.name:
   >         return _origcopyfileobj(fsrc, fdst, length)
   >     fdst.write(fsrc.read(4))
   >     raise IOError(errno.ENOSPC, os.strerror(errno.ENOSPC))