From 87ba4c17644d95ed4745495c7f1a95f02a0c2b40 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gabriel=20Fr=C3=B3es=20Franco?= <gffranco@gmail.com>
Date: Sun, 31 May 2026 21:45:50 -0300
Subject: [PATCH] test(calendar): add Vim + Neovim integration harnesses

Add headless harnesses covering the calendar-vim integration, wired into
CI alongside the existing keymap/config suites:

- test-calendar-vim.sh/.vim (+ -optout.vim): pure-VimL diary hooks
  (calendar_sign markers, calendar_action path resolution from wiki root,
  calendar window close), plugin/nuwiki.vim hook auto-wiring that
  overrides calendar-vim's defaults, and opt-out via g:nuwiki_use_calendar
  and g:nuwiki_no_calendar. Uses a stub calendar-vim on the runtimepath.
- test-calendar.sh/.lua: Neovim setup() wiring + window-close under the
  real window API, and opt-out via use_calendar = false.

Fixes surfaced by the suite:
- diary.vim: new diary entries set filetype 'vimwiki' (was the raw
  extension, e.g. 'wiki'); the stray FileType autocmd also blocked the
  calendar window from closing.
- init.lua: drop the redundant Neovim FileType autocmd (plugin/nuwiki.vim
  already wires both editors) and translate use_calendar=false into
  g:nuwiki_no_calendar so the opt-out actually disables wiring.
---
 .gitea/workflows/ci.yaml                      |   4 +
 autoload/nuwiki/diary.vim                     |  10 +-
 development/ONBOARDING.md                     |   7 +-
 .../tests/test-calendar-vim-optout.vim        |  40 ++++++
 development/tests/test-calendar-vim.sh        | 121 ++++++++++++++++++
 development/tests/test-calendar-vim.vim       |  97 ++++++++++++++
 development/tests/test-calendar.lua           |  92 +++++++++++++
 development/tests/test-calendar.sh            | 106 +++++++++++++++
 lua/nuwiki/init.lua                           |  25 +---
 9 files changed, 475 insertions(+), 27 deletions(-)
 create mode 100644 development/tests/test-calendar-vim-optout.vim
 create mode 100755 development/tests/test-calendar-vim.sh
 create mode 100644 development/tests/test-calendar-vim.vim
 create mode 100644 development/tests/test-calendar.lua
 create mode 100755 development/tests/test-calendar.sh

diff --git a/.gitea/workflows/ci.yaml b/.gitea/workflows/ci.yaml
index 2eed90b..2ce8798 100644
--- a/.gitea/workflows/ci.yaml
+++ b/.gitea/workflows/ci.yaml
@@ -100,3 +100,7 @@ jobs:
         run: ./development/tests/test-config.sh
       - name: run Vim config parity harness
         run: ./development/tests/test-config-vim.sh
+      - name: run Neovim calendar integration harness
+        run: ./development/tests/test-calendar.sh
+      - name: run Vim calendar integration harness
+        run: ./development/tests/test-calendar-vim.sh
diff --git a/autoload/nuwiki/diary.vim b/autoload/nuwiki/diary.vim
index 40bbfa3..a6c28b2 100644
--- a/autoload/nuwiki/diary.vim
+++ b/autoload/nuwiki/diary.vim
@@ -34,12 +34,10 @@ function! nuwiki#diary#calendar_action(day, month, year, week, dir) abort
   endif
 
   execute 'edit ' . fnameescape(l:file_path)
-  if !filereadable(l:file_path)
-    if l:c.ext[0] ==# '.'
-      execute 'setfiletype ' . l:c.ext[1:]
-    else
-      execute 'setfiletype ' . l:c.ext
-    endif
+  " A brand-new entry has no file on disk yet, so ftdetect may not have run;
+  " ensure the vimwiki filetype so syntax/maps are active immediately.
+  if &filetype !=# 'vimwiki'
+    setfiletype vimwiki
   endif
 
   " Close the calendar window now that the diary is open (keep at least one).
diff --git a/development/ONBOARDING.md b/development/ONBOARDING.md
index c9370cb..1909afd 100644
--- a/development/ONBOARDING.md
+++ b/development/ONBOARDING.md
@@ -79,7 +79,12 @@ nuwiki/
 │       ├── test-keymaps.sh     # Neovim keymap harness
 │       ├── test-keymaps.lua
 │       ├── test-keymaps-vim.sh # Vim keymap harness
-│       └── test-keymaps-vim.vim
+│       ├── test-keymaps-vim.vim
+│       ├── test-calendar.sh    # Neovim calendar-vim integration harness
+│       ├── test-calendar.lua
+│       ├── test-calendar-vim.sh # Vim calendar-vim integration harness
+│       ├── test-calendar-vim.vim
+│       └── test-calendar-vim-optout.vim
 │
 └── .gitea/
     └── workflows/
diff --git a/development/tests/test-calendar-vim-optout.vim b/development/tests/test-calendar-vim-optout.vim
new file mode 100644
index 0000000..07340d1
--- /dev/null
+++ b/development/tests/test-calendar-vim-optout.vim
@@ -0,0 +1,40 @@
+" development/tests/test-calendar-vim-optout.vim — driven by test-calendar-vim.sh.
+"
+" Asserts that the calendar-vim integration stays OFF when the user opts out
+" (g:nuwiki_use_calendar = 0 or g:nuwiki_no_calendar = 1). In that case the
+" FileType autocmd must leave calendar-vim's own defaults untouched, so the
+" hooks still point at 'calendar#diary' / 'calendar#sign' (set by the stub).
+
+let s:results = []
+let s:pass = 0
+let s:fail = 0
+let s:out = $NUWIKI_CALENDAR_RESULTS
+
+function! s:record(ok, name, detail) abort
+  let l:line = (a:ok ? 'PASS' : 'FAIL') . ' ' . a:name
+  if a:detail !=# ''
+    let l:line .= ' — ' . a:detail
+  endif
+  call add(s:results, l:line)
+  if a:ok
+    let s:pass += 1
+  else
+    let s:fail += 1
+  endif
+endfunction
+
+" The buffer is already a loaded vimwiki file (FileType has fired). nuwiki must
+" NOT have rewired the hooks — they should still be calendar-vim's defaults.
+call s:record(&filetype ==# 'vimwiki', 'ftplugin.attached',
+      \ &filetype ==# 'vimwiki' ? '' : 'filetype=' . &filetype)
+call s:record(get(g:, 'calendar_action', '') !=# 'vimwiki#diary#calendar_action',
+      \ 'optout.action_not_wired',
+      \ 'g:calendar_action=' . get(g:, 'calendar_action', ''))
+call s:record(get(g:, 'calendar_sign', '') !=# 'vimwiki#diary#calendar_sign',
+      \ 'optout.sign_not_wired',
+      \ 'g:calendar_sign=' . get(g:, 'calendar_sign', ''))
+
+call add(s:results, '')
+call add(s:results, printf('SUMMARY: %d passed, %d failed', s:pass, s:fail))
+call writefile(s:results, s:out)
+execute (s:fail == 0 ? 'qall!' : 'cquit!')
diff --git a/development/tests/test-calendar-vim.sh b/development/tests/test-calendar-vim.sh
new file mode 100755
index 0000000..455f479
--- /dev/null
+++ b/development/tests/test-calendar-vim.sh
@@ -0,0 +1,121 @@
+#!/usr/bin/env bash
+#
+# development/tests/test-calendar-vim.sh — calendar-vim integration harness (Vim).
+#
+# Exercises the pure-VimL diary hooks (nuwiki#diary#calendar_action /
+# nuwiki#diary#calendar_sign) plus plugin/nuwiki.vim's auto-wiring of
+# g:calendar_action / g:calendar_sign. A stub calendar-vim is placed on the
+# runtimepath so :Calendar exists and the hooks start at calendar-vim's own
+# defaults — the exact state nuwiki must detect and override.
+#
+# Two runs:
+#   1. default      → integration ON, hooks rewired, diary paths from wiki root
+#   2. opt-out       → g:nuwiki_use_calendar=0 / g:nuwiki_no_calendar=1 leave
+#                      calendar-vim's defaults untouched
+#
+# No LSP binary is needed — the diary hooks are entirely client-side VimL.
+# Exit code: 0 when all assertions pass, 1 otherwise. Skips (0) without vim.
+
+set -euo pipefail
+
+REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
+TMP="$(mktemp -d -t nuwiki-calendar-vim-test-XXXXXX)"
+trap 'rm -rf "$TMP"' EXIT
+
+log() { printf '\033[1;34m[calendar-vim]\033[0m %s\n' "$*"; }
+
+if ! command -v vim >/dev/null 2>&1; then
+  log 'vim not installed — skipping'
+  exit 0
+fi
+
+# --- Scratch wiki with one seeded diary entry (2026-05-30) ----------------
+WIKI="$TMP/wiki"
+mkdir -p "$WIKI/diary"
+echo "= index =" > "$WIKI/index.wiki"
+echo "= 2026-05-30 =" > "$WIKI/diary/2026-05-30.wiki"
+
+# --- Stub calendar-vim ----------------------------------------------------
+# Mimics the real plugin closely enough for detection + the override path:
+# defines :Calendar and seeds calendar-vim's default hook names.
+CAL="$TMP/calendar-vim"
+mkdir -p "$CAL/plugin" "$CAL/autoload"
+cat > "$CAL/plugin/calendar.vim" <<'EOF'
+if exists('g:loaded_calendar_stub') | finish | endif
+let g:loaded_calendar_stub = 1
+let g:calendar_action = get(g:, 'calendar_action', 'calendar#diary')
+let g:calendar_sign   = get(g:, 'calendar_sign', 'calendar#sign')
+command! -nargs=* Calendar echo 'stub calendar'
+EOF
+cat > "$CAL/autoload/calendar.vim" <<'EOF'
+function! calendar#open(...) abort
+endfunction
+function! calendar#diary(...) abort
+endfunction
+function! calendar#sign(...) abort
+  return 0
+endfunction
+EOF
+
+run_harness() {
+  local label="$1" vimrc="$2" harness="$3"
+  local results="$TMP/results-$label.txt"
+  log "running $label harness…"
+  NUWIKI_CALENDAR_RESULTS="$results" \
+  NUWIKI_CALENDAR_WIKI="$WIKI" \
+    timeout 30 vim -e -s -u "$vimrc" -c "edit $WIKI/index.wiki" \
+      -c "source $harness" </dev/null >"$TMP/$label.log" 2>&1 || true
+  if [[ ! -f "$results" ]]; then
+    echo "calendar $label harness produced no output" >&2
+    echo "--- vim log ---" >&2
+    cat "$TMP/$label.log" >&2 || true
+    return 1
+  fi
+  cat "$results"
+  grep -qE '^SUMMARY: [0-9]+ passed, 0 failed' "$results"
+}
+
+# --- Run 1: default (integration ON) --------------------------------------
+VIMRC="$TMP/vimrc"
+cat > "$VIMRC" <<EOF
+set nocompatible
+let &runtimepath = '$REPO_ROOT' . ',' . &runtimepath
+let &runtimepath .= ',$CAL'
+let g:nuwiki_wiki_root = '$WIKI'
+let g:nuwiki_file_extension = '.wiki'
+let g:nuwiki_diary_rel_path = 'diary'
+set hidden
+filetype plugin indent on
+syntax enable
+EOF
+
+# --- Run 2: opt-out via g:nuwiki_use_calendar = 0 -------------------------
+VIMRC_OPTOUT="$TMP/vimrc-optout"
+cat > "$VIMRC_OPTOUT" <<EOF
+set nocompatible
+let &runtimepath = '$REPO_ROOT' . ',' . &runtimepath
+let &runtimepath .= ',$CAL'
+let g:nuwiki_use_calendar = 0
+let g:nuwiki_wiki_root = '$WIKI'
+filetype plugin indent on
+syntax enable
+EOF
+
+# --- Run 3: opt-out via g:nuwiki_no_calendar = 1 --------------------------
+VIMRC_NOCAL="$TMP/vimrc-nocal"
+cat > "$VIMRC_NOCAL" <<EOF
+set nocompatible
+let &runtimepath = '$REPO_ROOT' . ',' . &runtimepath
+let &runtimepath .= ',$CAL'
+let g:nuwiki_no_calendar = 1
+let g:nuwiki_wiki_root = '$WIKI'
+filetype plugin indent on
+syntax enable
+EOF
+
+rc=0
+run_harness 'default' "$VIMRC" "$REPO_ROOT/development/tests/test-calendar-vim.vim" || rc=1
+run_harness 'optout-use' "$VIMRC_OPTOUT" "$REPO_ROOT/development/tests/test-calendar-vim-optout.vim" || rc=1
+run_harness 'optout-no' "$VIMRC_NOCAL" "$REPO_ROOT/development/tests/test-calendar-vim-optout.vim" || rc=1
+
+exit $rc
diff --git a/development/tests/test-calendar-vim.vim b/development/tests/test-calendar-vim.vim
new file mode 100644
index 0000000..d50dabc
--- /dev/null
+++ b/development/tests/test-calendar-vim.vim
@@ -0,0 +1,97 @@
+" development/tests/test-calendar-vim.vim — driven by development/tests/test-calendar-vim.sh.
+"
+" Pure-VimL regression suite for the calendar-vim integration. The diary
+" hooks (nuwiki#diary#calendar_action / nuwiki#diary#calendar_sign) are
+" implemented entirely in VimL and shared verbatim by the Vim and Neovim
+" clients, so this harness is the canonical coverage for them. The Vim
+" plugin-side hook wiring (plugin/nuwiki.vim's FileType autocmd) is also
+" asserted here; the Neovim setup() wiring has its own harness in
+" development/tests/test-calendar.lua.
+"
+" A stub calendar-vim is placed on the runtimepath by the shell wrapper so
+" :Calendar exists and g:calendar_action/g:calendar_sign already hold
+" calendar-vim's own defaults ('calendar#diary'/'calendar#sign') — exactly
+" the state nuwiki must detect and override.
+
+let s:results = []
+let s:pass = 0
+let s:fail = 0
+let s:out = $NUWIKI_CALENDAR_RESULTS
+
+function! s:record(ok, name, detail) abort
+  let l:line = (a:ok ? 'PASS' : 'FAIL') . ' ' . a:name
+  if a:detail !=# ''
+    let l:line .= ' — ' . a:detail
+  endif
+  call add(s:results, l:line)
+  if a:ok
+    let s:pass += 1
+  else
+    let s:fail += 1
+  endif
+endfunction
+
+let s:wiki_root = $NUWIKI_CALENDAR_WIKI
+
+" ===== Hook wiring: nuwiki overrides calendar-vim's defaults =====
+" The stub set g:calendar_action='calendar#diary' / g:calendar_sign='calendar#sign'
+" at load. Opening this .wiki buffer fired plugin/nuwiki.vim's FileType autocmd,
+" which must have rewired both to the nuwiki delegators.
+
+call s:record(&filetype ==# 'vimwiki', 'ftplugin.attached',
+      \ &filetype ==# 'vimwiki' ? '' : 'filetype=' . &filetype)
+call s:record(get(g:, 'calendar_action', '') ==# 'vimwiki#diary#calendar_action',
+      \ 'hook.action_wired', 'g:calendar_action=' . get(g:, 'calendar_action', ''))
+call s:record(get(g:, 'calendar_sign', '') ==# 'vimwiki#diary#calendar_sign',
+      \ 'hook.sign_wired', 'g:calendar_sign=' . get(g:, 'calendar_sign', ''))
+
+" ===== calendar_sign: marker reflects diary-file existence =====
+" The shell seeded a diary entry for 2026-05-30 and left 2026-05-31 absent.
+
+call s:record(nuwiki#diary#calendar_sign(30, 5, 2026) ==# '*',
+      \ 'sign.existing_date_marked',
+      \ 'got ' . string(nuwiki#diary#calendar_sign(30, 5, 2026)))
+call s:record(nuwiki#diary#calendar_sign(31, 5, 2026) ==# '',
+      \ 'sign.absent_date_unmarked',
+      \ 'got ' . string(nuwiki#diary#calendar_sign(31, 5, 2026)))
+" The vimwiki# alias must return the identical result.
+call s:record(vimwiki#diary#calendar_sign(30, 5, 2026) ==# '*',
+      \ 'sign.alias_matches', '')
+
+" ===== calendar_action: opens WIKI_ROOT/diary/<date>.wiki, not ~/diary =====
+" Set up two windows so the "previous window" branch runs and we can assert
+" the calendar window is closed afterwards.
+
+" Window A: the seed wiki (already current). Open a fresh window to stand in
+" for the calendar, then invoke the action from it.
+new
+file [stub-calendar]
+let s:cal_winid = win_getid()
+let s:wins_before = winnr('$')
+call nuwiki#diary#calendar_action(31, 5, 2026, 0, '')
+
+let s:opened = expand('%:p')
+let s:want = s:wiki_root . '/diary/2026-05-31.wiki'
+call s:record(s:opened ==# s:want, 'action.opens_wiki_diary_path',
+      \ 'opened=' . s:opened)
+call s:record(s:opened !~# '/diary/2026-05-31.wiki$' ? 0 : 1,
+      \ 'action.path_has_date_filename', 'opened=' . s:opened)
+call s:record(s:opened !~# expand('~') . '/diary',
+      \ 'action.not_home_diary', 'opened=' . s:opened)
+
+" The calendar window must be closed once the diary is open.
+call s:record(win_id2win(s:cal_winid) == 0, 'action.closes_calendar_window',
+      \ 'cal still at win ' . win_id2win(s:cal_winid))
+call s:record(winnr('$') == s:wins_before - 1, 'action.window_count_decremented',
+      \ 'before=' . s:wins_before . ' after=' . winnr('$'))
+
+" ===== calendar_action sets the wiki filetype on a new entry =====
+call s:record(&filetype ==# 'vimwiki', 'action.sets_filetype',
+      \ 'filetype=' . &filetype)
+
+" ===== Wrap up =====
+
+call add(s:results, '')
+call add(s:results, printf('SUMMARY: %d passed, %d failed', s:pass, s:fail))
+call writefile(s:results, s:out)
+execute (s:fail == 0 ? 'qall!' : 'cquit!')
diff --git a/development/tests/test-calendar.lua b/development/tests/test-calendar.lua
new file mode 100644
index 0000000..3210a44
--- /dev/null
+++ b/development/tests/test-calendar.lua
@@ -0,0 +1,92 @@
+-- development/tests/test-calendar.lua — driven by development/tests/test-calendar.sh.
+--
+-- Headless Neovim harness for the calendar-vim integration wired through
+-- `require('nuwiki').setup()`. The diary hooks themselves are pure VimL and
+-- covered exhaustively by development/tests/test-calendar-vim.vim; this
+-- harness focuses on the Neovim-only pieces:
+--   * setup() registering the FileType autocmd that overrides calendar-vim's
+--     own default hooks ('calendar#diary' / 'calendar#sign'),
+--   * the window-close behaviour of calendar_action under the real (non-ex)
+--     window API,
+--   * disabling via use_calendar = false.
+--
+-- The opt-out case runs in a second nvim invocation (see the shell wrapper)
+-- because setup() registers the autocmd once per process.
+--
+-- Results are written to $NUWIKI_CALENDAR_RESULTS so the wrapper can render
+-- them without scraping nvim's output.
+
+local OUT = vim.env.NUWIKI_CALENDAR_RESULTS or '/tmp/nuwiki-calendar-results.txt'
+local WIKI = vim.env.NUWIKI_CALENDAR_WIKI
+local MODE = vim.env.NUWIKI_CALENDAR_MODE or 'default'
+local out_lines = {}
+local pass, fail = 0, 0
+
+local function record(ok, name, detail)
+  local suffix = (detail and detail ~= '') and (' — ' .. detail) or ''
+  table.insert(out_lines, (ok and 'PASS' or 'FAIL') .. ' ' .. name .. suffix)
+  if ok then pass = pass + 1 else fail = fail + 1 end
+end
+
+local function finish()
+  table.insert(out_lines, '')
+  table.insert(out_lines, string.format('SUMMARY: %d passed, %d failed', pass, fail))
+  vim.fn.writefile(out_lines, OUT)
+  vim.cmd(fail == 0 and 'qall!' or 'cquit!')
+end
+
+-- Open the seeded wiki index so the FileType vimwiki autocmd fires.
+vim.cmd('edit ' .. vim.fn.fnameescape(WIKI .. '/index.wiki'))
+
+if MODE == 'optout' then
+  -- use_calendar = false: setup() must not register the wiring autocmd, so
+  -- calendar-vim's own defaults (set by the stub) survive untouched.
+  record(vim.bo.filetype == 'vimwiki', 'optout.ftplugin_attached',
+    'filetype=' .. vim.bo.filetype)
+  record(vim.g.calendar_action ~= 'vimwiki#diary#calendar_action',
+    'optout.action_not_wired', 'g:calendar_action=' .. tostring(vim.g.calendar_action))
+  record(vim.g.calendar_sign ~= 'vimwiki#diary#calendar_sign',
+    'optout.sign_not_wired', 'g:calendar_sign=' .. tostring(vim.g.calendar_sign))
+  finish()
+  return
+end
+
+-- ===== Hook wiring overrides calendar-vim defaults =====
+record(vim.bo.filetype == 'vimwiki', 'ftplugin_attached',
+  'filetype=' .. vim.bo.filetype)
+record(vim.g.calendar_action == 'vimwiki#diary#calendar_action',
+  'hook.action_wired', 'g:calendar_action=' .. tostring(vim.g.calendar_action))
+record(vim.g.calendar_sign == 'vimwiki#diary#calendar_sign',
+  'hook.sign_wired', 'g:calendar_sign=' .. tostring(vim.g.calendar_sign))
+
+-- ===== calendar_sign reflects diary-file existence =====
+record(vim.fn['nuwiki#diary#calendar_sign'](30, 5, 2026) == '*',
+  'sign.existing_date_marked',
+  'got ' .. tostring(vim.fn['nuwiki#diary#calendar_sign'](30, 5, 2026)))
+record(vim.fn['nuwiki#diary#calendar_sign'](31, 5, 2026) == '',
+  'sign.absent_date_unmarked',
+  'got ' .. tostring(vim.fn['nuwiki#diary#calendar_sign'](31, 5, 2026)))
+
+-- ===== calendar_action: path + window-close (real window API) =====
+-- Open a second window to act as the calendar, invoke from it, and confirm
+-- the diary lands at WIKI/diary/<date>.wiki while the calendar window closes.
+vim.cmd('new')
+local cal_win = vim.api.nvim_get_current_win()
+local wins_before = #vim.api.nvim_list_wins()
+vim.fn['nuwiki#diary#calendar_action'](31, 5, 2026, 0, '')
+
+local opened = vim.fn.expand('%:p')
+local want = WIKI .. '/diary/2026-05-31.wiki'
+record(opened == want, 'action.opens_wiki_diary_path', 'opened=' .. opened)
+record(not opened:match(vim.fn.expand('~') .. '/diary'),
+  'action.not_home_diary', 'opened=' .. opened)
+record(not vim.api.nvim_win_is_valid(cal_win),
+  'action.closes_calendar_window',
+  'cal_win valid=' .. tostring(vim.api.nvim_win_is_valid(cal_win)))
+record(#vim.api.nvim_list_wins() == wins_before - 1,
+  'action.window_count_decremented',
+  'before=' .. wins_before .. ' after=' .. #vim.api.nvim_list_wins())
+record(vim.bo.filetype == 'vimwiki', 'action.sets_filetype',
+  'filetype=' .. vim.bo.filetype)
+
+finish()
diff --git a/development/tests/test-calendar.sh b/development/tests/test-calendar.sh
new file mode 100755
index 0000000..e7fe1b2
--- /dev/null
+++ b/development/tests/test-calendar.sh
@@ -0,0 +1,106 @@
+#!/usr/bin/env bash
+#
+# development/tests/test-calendar.sh — calendar-vim integration harness (Neovim).
+#
+# Drives development/tests/test-calendar.lua under headless Neovim to cover the
+# pieces specific to the Lua entry point:
+#   * require('nuwiki').setup() wiring g:calendar_action / g:calendar_sign and
+#     overriding calendar-vim's own defaults,
+#   * calendar_action's window-close behaviour under the real window API,
+#   * opting out with use_calendar = false.
+#
+# A stub calendar-vim on the runtimepath provides :Calendar and seeds the
+# default hook names. The LSP binary is built (setup() registers the client);
+# the calendar paths themselves don't need the server.
+#
+# Exit: 0 when both runs are green, 1 otherwise. Skips (0) without nvim.
+
+set -euo pipefail
+
+REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
+TMP="$(mktemp -d -t nuwiki-calendar-test-XXXXXX)"
+trap 'rm -rf "$TMP"' EXIT
+
+log() { printf '\033[1;34m[calendar]\033[0m %s\n' "$*"; }
+
+if ! command -v nvim >/dev/null 2>&1; then
+  log 'nvim not installed — skipping'
+  exit 0
+fi
+
+# setup() registers the LSP client, so build the binary like the other
+# Neovim harnesses do (incremental, fast).
+BIN="$REPO_ROOT/bin/nuwiki-ls"
+log 'building nuwiki-ls (release, incremental)…'
+cargo build --release -p nuwiki-ls --manifest-path "$REPO_ROOT/Cargo.toml" >/dev/null
+mkdir -p "$REPO_ROOT/bin"
+ln -sf "$REPO_ROOT/target/release/nuwiki-ls" "$BIN"
+
+# --- Scratch wiki with one seeded diary entry (2026-05-30) ----------------
+WIKI="$TMP/wiki"
+mkdir -p "$WIKI/diary"
+echo "= index =" > "$WIKI/index.wiki"
+echo "= 2026-05-30 =" > "$WIKI/diary/2026-05-30.wiki"
+
+# --- Stub calendar-vim ----------------------------------------------------
+CAL="$TMP/calendar-vim"
+mkdir -p "$CAL/plugin" "$CAL/autoload"
+cat > "$CAL/plugin/calendar.vim" <<'EOF'
+if exists('g:loaded_calendar_stub') | finish | endif
+let g:loaded_calendar_stub = 1
+let g:calendar_action = get(g:, 'calendar_action', 'calendar#diary')
+let g:calendar_sign   = get(g:, 'calendar_sign', 'calendar#sign')
+command! -nargs=* Calendar echo 'stub calendar'
+EOF
+cat > "$CAL/autoload/calendar.vim" <<'EOF'
+function! calendar#open(...) abort
+endfunction
+function! calendar#diary(...) abort
+endfunction
+function! calendar#sign(...) abort
+  return 0
+endfunction
+EOF
+
+write_init() {
+  local file="$1" use_calendar="$2"
+  cat > "$file" <<EOF
+vim.opt.runtimepath:prepend('$REPO_ROOT')
+vim.opt.runtimepath:append('$CAL')
+vim.g.nuwiki_binary_path = '$BIN'
+vim.g.nuwiki_wiki_root = '$WIKI'
+vim.g.nuwiki_file_extension = '.wiki'
+vim.g.nuwiki_diary_rel_path = 'diary'
+require('nuwiki').setup({ wiki_root = '$WIKI', use_calendar = $use_calendar })
+EOF
+}
+
+run() {
+  local label="$1" init="$2" mode="$3"
+  local results="$TMP/results-$label.txt"
+  log "running $label harness…"
+  NUWIKI_CALENDAR_RESULTS="$results" \
+  NUWIKI_CALENDAR_WIKI="$WIKI" \
+  NUWIKI_CALENDAR_MODE="$mode" \
+    timeout 60 nvim --clean -u "$init" --headless \
+      -c "luafile $REPO_ROOT/development/tests/test-calendar.lua" \
+      >"$TMP/$label.log" 2>&1 || true
+  if [[ ! -f "$results" ]]; then
+    echo "calendar $label harness produced no output" >&2
+    echo "--- nvim log ---" >&2
+    cat "$TMP/$label.log" >&2 || true
+    return 1
+  fi
+  cat "$results"
+  grep -qE '^SUMMARY: [0-9]+ passed, 0 failed' "$results"
+}
+
+INIT_ON="$TMP/init-on.lua"
+INIT_OFF="$TMP/init-off.lua"
+write_init "$INIT_ON" 'true'
+write_init "$INIT_OFF" 'false'
+
+rc=0
+run 'default' "$INIT_ON" 'default' || rc=1
+run 'optout' "$INIT_OFF" 'optout' || rc=1
+exit $rc
diff --git a/lua/nuwiki/init.lua b/lua/nuwiki/init.lua
index 444915f..a5479b5 100644
--- a/lua/nuwiki/init.lua
+++ b/lua/nuwiki/init.lua
@@ -85,26 +85,11 @@ function M.setup(opts)
     vim.filetype.add({ extension = extensions })
   end
 
-  -- Auto-detect calendar-vim and wire hooks when the first vimwiki buffer loads.
-  -- On by default; disable with use_calendar = false or g:nuwiki_no_calendar.
-  if config.options.use_calendar ~= false and not config.options.no_calendar then
-    vim.api.nvim_create_autocmd('FileType', {
-      pattern = 'vimwiki',
-      callback = function()
-        if vim.fn.exists('*calendar#open') == 1 or vim.fn.exists(':Calendar') == 2 then
-          -- Overwrite calendar-vim's own defaults (which write to ~/diary)
-          -- but respect a user-set custom hook.
-          local act = vim.g.calendar_action
-          if not act or act == '' or act == 'calendar#diary' then
-            vim.g.calendar_action = 'vimwiki#diary#calendar_action'
-          end
-          local sign = vim.g.calendar_sign
-          if not sign or sign == '' or sign == 'calendar#sign' then
-            vim.g.calendar_sign = 'vimwiki#diary#calendar_sign'
-          end
-        end
-      end,
-    })
+  -- Calendar-vim wiring lives in plugin/nuwiki.vim's FileType autocmd, which
+  -- runs for both Vim and Neovim. Translate the Lua-side opt-out into the
+  -- g: flag that autocmd reads so `use_calendar = false` fully disables it.
+  if config.options.use_calendar == false then
+    vim.g.nuwiki_no_calendar = 1
   end
 
   lsp.register()