[harleypig]

Summary

Finishes the behaviour tests for our own settings, area by area. Each
commit covers one area of #71's checklist. Tests only: no settings file
changes, and no test found a bug.

Closes #71

Areas: which tests cover each

• Options (plugin/set.vim, plugin/xdg-settings.vim):
  set.bats (every section of set.vim, read after full startup),
  old-files.bats (new: the 90-day and 180-day cleanup, everything else
  left alone, the backup and viminfo options), xdg.bats, tidy.bats
• Mappings (plugin/maps.vim, plugin/help.vim): maps.bats,
  tidy.bats, maps-rest.bats (new: <Leader>tt, Ctrl-L, <Leader>fb),
  help.bats (new: help in a right-hand vertical split, its buffer-local
  Enter and Ctrl-[), quickfix.bats (the <Leader>q* mappings)
• Quickfix (autoload/quickfixtoggle.vim): quickfix.bats (new:
  opens and returns focus, a second call closes, a lone location list is
  not read as quickfix, :QuickfixToggle, <Leader>qf, <Leader>q] and
  <Leader>q[)
• Display: plugin/diagnostic-colors.vim in colors.bats and
  diagnostic-colors.bats (new: the palette survives a colour scheme
  loading); plugin/gutter.vim in tidy.bats and gutter.bats (new:
  startup values, the sign toggle's branches with numbers off and
  relative-only); after/plugin/statusline.vim in statusline.bats,
  colors.bats and statusline-parts.bats (new: each branch of
  YASL_BufferInfo() and YASL_Warnings(), YASL_FileSize() at 0, 1,
  1023, 1024, 1 MiB - 1 and 1 MiB, the assembled statusline).
  plugin/colors.vim and after/diff.vim were removed in Remove inert code: tools/, checkfiletype, diff, bats, virtual text, mustache #124 (after/diff.vim is never loaded: remove, move, or note #98), so
  there is nothing of theirs to test.
• Linting (early and late plugin/ale.vim): ale-settings.bats,
  ale-linters.bats, load.bats, ale-values.bats (new: early values
  read as ALE's plugin is about to load; the late global linters and
  fixers exactly; both still whole after every ftplugin's filetype has
  been opened, Opening a Python or bats buffer wipes json's ALE fixer setting #77)
• Filetype detection (plugin/checkfiletype.vim): removed in
  Remove inert code: tools/, checkfiletype, diff, bats, virtual text, mustache #124 after checkfiletype.vim and the git ftplugin are inert: remove, make work, or note #97 found it inert, so there is nothing to test. The Ansible
  detection tests in load.bats cover what detects filetypes now.
• Per-language settings (after/ftplugin/): hcl, java, python,
  sh, terraform, vim and yaml in ftplugins.bats (new); json in
  load.bats; markdown in ale-settings.bats and intellisense.bats;
  linter names in ale-linters.bats; sh's shfmt command in
  sh-ftplugin.bats; python's and yaml's other cases in tidy.bats and
  load.bats
• Help tags (after/plugin/helptags.vim): helptags.bats

Two lines are left untested, because silent Ex mode cannot show them:

• set.vim's t_ti= and t_te=. Vim in -es loads no termcap, so both
  read empty whatever set.vim does. set.bats's header says so.
• help.vim's resize to at most 80 columns. In -es no window is wider
  than 80 columns, whatever columns is set to, so the resize never has
  anything to do. help.bats's header says so.

Test plan

• bats tests/vim with a fresh, empty TMPDIR: 146 tests, all ok, and
  the directory was still empty afterwards.
• Every new test was seen red. For each one, the line it guards in the
  settings file was changed (a value, a boundary, a branch condition, a
  mapping target, or the line deleted), the file was run, and the
  settings file was put back. Each change turned the expected test red.
  The exception is in the next section.
• CI (bats tests/vim on Ubuntu 24.04's Vim 9.1.0016) failed on the
  first push because of two ways CI's Vim differs from the local one. It
  has no +clipboard, so set.vim's clipboard line does nothing there.
  Its own syntax/sh.vim also writes the errors a silent! hides into an
  active redirect. The last commit fixes both: the clipboard check runs
  only where exists('+clipboard'), and errors are read from the message
  history, as load.bats reads them. CI is now green.

Testing evaluation

Done by the agent that opened this PR, to the qa-tester's standard. No
team-managed: sentinel is declared.

1. Verdict: this PR is the tests. The settings code is unchanged.
2. Automatable: yes, all of it, in bats under tests/vim/.
3. Falsifiers: each test was seen red against a change to the line it
   guards (see Test plan). One case does not have that falsifier:
   terraform's commentstring, foldmethod and b:ale_fixers. Deleting
   them from terraform.vim leaves the test green, because
   vim-polyglot's terraform ftplugin runs runtime! ftplugin/hcl.vim,
   which also sources our after/ftplugin/hcl.vim. The test asserts what a
   terraform buffer ends up with and says where the values come from. The
   tflint linter does come only from terraform.vim, and deleting it turns
   the test red.
4. Disposition: written in this PR.
5. Entry-point reach: mappings were driven through :normal on their
   keys, the toggle through its function, its command and its mapping, and
   the early ALE values through an autocmd that fires as ALE's own plugin
   file loads.

Manual verification

1. From a checkout of this branch with submodules initialised
   (git submodule update --init) and BATS_LIB_PATH pointing at
   bats-support and bats-assert.
2. Run bats tests/vim.
3. Success: every line starts with ok, the last test is number 146, and
   the exit status is 0.
4. Failure: change a value one of the new tests guards, for example
   textwidth=78 to textwidth=80 in the late plugin/set.vim. Run
   bats tests/vim/set.bats and not ok 6 wrapping: … appears.

What happened: step 2 printed 1..146, every line ok, exit status
0. Step 4 printed not ok 6 wrapping: format options, backspace over everything, 78 columns, and after set.vim was restored the file ran
green.

Review

The diff was reviewed by its author: each test was checked to read what
the settings file sets rather than what Vim or a plugin does with it
(.claude/TESTS.md), to fail on a broken setting, and not to depend on
the local Vim. Tests that open sh or java buffers read errors from the
message history, as load.bats does. They do not read v:errmsg or the
redirect, because CI's Vim fills both from its own syntax/sh.vim.

opt-out: no review skill ran. The diff adds tests and changes no
settings, and each test was checked by breaking the line it guards and
seeing it go red, which covers what a diff review would look for here.

Completion report

1. The functionality works: met. The suite passes locally, and CI is
   watched on this PR.
2. The access model is defined: not applicable. These are tests of a
   local editor configuration.
3. Permissions are implemented: not applicable, for the same reason.
4. Audit logging is implemented: not applicable, for the same reason.
5. Validation is complete: not applicable. There is no input boundary.
6. Errors are handled: met. Each test checks that Vim raised no error.
7. Testing is complete: met for every area. The two lines silent Ex mode
   cannot exercise are named above.
8. Documentation exists: met. Each new file's header says what it covers
   and which other files cover the rest. .claude/TESTS.md needs no
   change.
9. The AI Completion Report has been produced: this section.

Co-Authored-By: AI Agent noreply@harleypig.com