tests: add a substitution for ENOENT/ERROR_FILE_NOT_FOUND messages Automatic replacement seems better than trying to figure out a check-code rule. I didn't bother looking to see why the error message and file name is reversed in the annotate and histedit tests, based on Windows or not. I originally had this as a list of tuples, conditional on the platform. But there are a couple of 'No such file or directory' messages emitted by Mercurial itself, so unconditional is required for stability. There are also several variants of what I assume is 'connection refused' and 'unknown host' in test-clone.t and test-clonebundles.t for Docker, FreeBSD jails, etc. Yes, these are handled by (re) tags, but maybe it would be better to capture those strings in order to avoid whack-a-mole in future tests. All of this points to using a dictionary containing one or more strings-to-be-replaced values.

--- a/tests/test-addremove.t	Sun Dec 03 20:55:35 2017 -0800
+++ b/tests/test-addremove.t	Sat Dec 02 19:33:34 2017 -0500
@@ -31,8 +31,7 @@
   $ hg forget foo
 
   $ hg -v addremove nonexistent
-  nonexistent: The system cannot find the file specified (windows !)
-  nonexistent: No such file or directory (no-windows !)
+  nonexistent: $ENOENT$
   [1]
 
   $ cd ..
@@ -86,8 +85,7 @@
   $ rm c
 
   $ hg ci -A -m "c" nonexistent
-  nonexistent: The system cannot find the file specified (windows !)
-  nonexistent: No such file or directory (no-windows !)
+  nonexistent: $ENOENT$
   abort: failed to mark all new/missing files as added/removed
   [255]