tests/test-empty.t

context: avoid breaking already fixed self._status at ctx.status()

Before this patch, "status()" on "workingcommitctx" with "always
match" object causes breaking "self._status" in
"workingctx._buildstatus()", because "workingctx._buildstatus()"
caches the result of "dirstate.status()" into "self._status" for
efficiency, even though it should be fixed at construction for
committing.

For example, template function "diff()" without any patterns in
"committemplate" implies "status()" on "workingcommitctx" with "always
match" object, via "basectx.diff()" and "patch.diff()".

Then, broken "self._status" causes committing unexpected files.

To avoid breaking already fixed "self._status" at "ctx.status()", this
patch overrides "_buildstatus" in "workingcommitctx".

This patch doesn't write out the result of template function "diff()"
in "committemplate" in "test-commit.t", because matching against files
to be committed still has an issue fixed in subsequent patch.

Create an empty repo:

  $ hg init a
  $ cd a

Try some commands:

  $ hg log
  $ hg grep wah
  [1]
  $ hg manifest
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  0 files, 0 changesets, 0 total revisions

Check the basic files created:

  $ ls .hg
  00changelog.i
  requires
  store

Should be empty:

  $ ls .hg/store

Poke at a clone:

  $ cd ..
  $ hg clone a b
  updating to branch default
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd b
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  0 files, 0 changesets, 0 total revisions
  $ ls .hg
  00changelog.i
  hgrc
  requires
  store

Should be empty:

  $ ls .hg/store

  $ cd ..