--- a/tests/test-unified-test.t	Sun Jun 28 18:02:45 2020 +0200
+++ b/tests/test-unified-test.t	Mon Jun 29 02:05:12 2020 +0200
@@ -75,6 +75,16 @@
   crlf\r (esc)
 #endif
 
+Escapes:
+
+  $ $PYTHON -c 'from mercurial.utils.procutil import stdout; stdout.write(b"\xff")'
+  \xff (no-eol) (esc)
+
+Escapes with conditions:
+
+  $ $PYTHON -c 'from mercurial.utils.procutil import stdout; stdout.write(b"\xff")'
+  \xff (no-eol) (esc) (true !)
+
 Combining esc with other markups - and handling lines ending with \r instead of \n:
 
   $ printf 'foo/bar\r'