test: use a more direct approach to test racy mutation
The previous test was relying on implementation details and harder to maintain.
The new version is closer to the initial intend : "What happens the file get overwritten from under the current process"
This change is motivated by further changes around the transaction and dirstate
logic that would break the fragile equilibrium that existed before this patch.
Making this change early make it easier to review on its own and remove noise
in future larger changes.
Mercurial
=========
Mercurial is a fast, easy to use, distributed revision control tool
for software developers.
Basic install::
$ make # see install targets
$ make install # do a system-wide install
$ hg debuginstall # sanity-check setup
$ hg # see help
Running without installing::
$ make local # build for inplace usage
$ ./hg --version # should show the latest version
See https://mercurial-scm.org/ for detailed installation
instructions, platform-specific notes, and Mercurial user information.
Notes for packagers
===================
Mercurial ships a copy of the python-zstandard sources. This is used to
provide support for zstd compression and decompression functionality. The
module is not intended to be replaced by the plain python-zstandard nor
is it intended to use a system zstd library. Patches can result in hard
to diagnose errors and are explicitly discouraged as unsupported
configuration.