test: reorg #15698

Problem:
Subdirectories like "visual", "insert", "normal" encourage people to
separate *related* tests for no good reason.  Typically the _mode_ is
not the relevant topic of a test (and when it is, _then_ create
an appropriate describe() or it()).

Solution:
- Delete the various `test/functional/<mode>/` subdirectories, move
  their tests to more meaningful topics.
- Rename `…/normal/` to `…/editor/`.
  - Move or merge `…/visual/*` and `…/insert/*` tests into here where
    appropriate.
- Rename `…/eval/` to `…/vimscript/`.
  - Move `…/viml/*` into here also.

* test(reorg): insert/* => editor/mode_insert_spec.lua
* test(reorg): cmdline/* => editor/mode_cmdline_spec.lua
* test(reorg): eval core tests => eval_spec.lua

41 files changed, 7046 insertions, 0 deletions

diff --git a/test/functional/vimscript/api_functions_spec.lua b/test/functional/vimscript/api_functions_spec.lua
new file mode 100644
index 0000000000..d07e74d40e
--- /dev/null
+++ b/test/functional/vimscript/api_functions_spec.lua
@@ -0,0 +1,167 @@
+local helpers = require('test.functional.helpers')(after_each)
+local Screen = require('test.functional.ui.screen')
+local lfs = require('lfs')
+local neq, eq, command = helpers.neq, helpers.eq, helpers.command
+local clear, curbufmeths = helpers.clear, helpers.curbufmeths
+local exc_exec, expect, eval = helpers.exc_exec, helpers.expect, helpers.eval
+local insert, pcall_err = helpers.insert, helpers.pcall_err
+local meths = helpers.meths
+
+describe('eval-API', function()
+  before_each(clear)
+
+  it("work", function()
+    command("call nvim_command('let g:test = 1')")
+    eq(1, eval("nvim_get_var('test')"))
+
+    local buf = eval("nvim_get_current_buf()")
+    command("call nvim_buf_set_lines("..buf..", 0, -1, v:true, ['aa', 'bb'])")
+    expect([[
+      aa
+      bb]])
+
+    command("call nvim_win_set_cursor(0, [1, 1])")
+    command("call nvim_input('ax<esc>')")
+    expect([[
+      aax
+      bb]])
+  end)
+
+  it("throw errors for invalid arguments", function()
+    local err = exc_exec('call nvim_get_current_buf("foo")')
+    eq('Vim(call):E118: Too many arguments for function: nvim_get_current_buf', err)
+
+    err = exc_exec('call nvim_set_option("hlsearch")')
+    eq('Vim(call):E119: Not enough arguments for function: nvim_set_option', err)
+
+    err = exc_exec('call nvim_buf_set_lines(1, 0, -1, [], ["list"])')
+    eq('Vim(call):E5555: API call: Wrong type for argument 4 when calling nvim_buf_set_lines, expecting Boolean', err)
+
+    err = exc_exec('call nvim_buf_set_lines(0, 0, -1, v:true, "string")')
+    eq('Vim(call):E5555: API call: Wrong type for argument 5 when calling nvim_buf_set_lines, expecting ArrayOf(String)', err)
+
+    err = exc_exec('call nvim_buf_get_number("0")')
+    eq('Vim(call):E5555: API call: Wrong type for argument 1 when calling nvim_buf_get_number, expecting Buffer', err)
+
+    err = exc_exec('call nvim_buf_line_count(17)')
+    eq('Vim(call):E5555: API call: Invalid buffer id: 17', err)
+  end)
+
+  it('cannot change texts if textlocked', function()
+    command("autocmd TextYankPost <buffer> ++once call nvim_buf_set_lines(0, 0, -1, v:false, [])")
+    eq('Vim(call):E5555: API call: E523: Not allowed here', pcall_err(command, "normal! yy"))
+  end)
+
+  it("use buffer numbers and windows ids as handles", function()
+    local screen = Screen.new(40, 8)
+    screen:attach()
+    local bnr = eval("bufnr('')")
+    local bhnd = eval("nvim_get_current_buf()")
+    local wid = eval("win_getid()")
+    local whnd = eval("nvim_get_current_win()")
+    eq(bnr, bhnd)
+    eq(wid, whnd)
+
+    command("new") -- creates new buffer and new window
+    local bnr2 = eval("bufnr('')")
+    local bhnd2 = eval("nvim_get_current_buf()")
+    local wid2 = eval("win_getid()")
+    local whnd2 = eval("nvim_get_current_win()")
+    eq(bnr2, bhnd2)
+    eq(wid2, whnd2)
+    neq(bnr, bnr2)
+    neq(wid, wid2)
+    -- 0 is synonymous to the current buffer
+    eq(bnr2, eval("nvim_buf_get_number(0)"))
+
+    command("bn") -- show old buffer in new window
+    eq(bnr, eval("nvim_get_current_buf()"))
+    eq(bnr, eval("bufnr('')"))
+    eq(bnr, eval("nvim_buf_get_number(0)"))
+    eq(wid2, eval("win_getid()"))
+    eq(whnd2, eval("nvim_get_current_win()"))
+  end)
+
+  it("get_lines and set_lines use NL to represent NUL", function()
+    curbufmeths.set_lines(0, -1, true, {"aa\0", "b\0b"})
+    eq({'aa\n', 'b\nb'}, eval("nvim_buf_get_lines(0, 0, -1, 1)"))
+
+    command('call nvim_buf_set_lines(0, 1, 2, v:true, ["xx", "\\nyy"])')
+    eq({'aa\0', 'xx', '\0yy'}, curbufmeths.get_lines(0, -1, 1))
+  end)
+
+  it("that are FUNC_ATTR_NOEVAL cannot be called", function()
+    -- Deprecated vim_ prefix is not exported.
+    local err = exc_exec('call vim_get_current_buffer("foo")')
+    eq('Vim(call):E117: Unknown function: vim_get_current_buffer', err)
+
+    -- Deprecated buffer_ prefix is not exported.
+    err = exc_exec('call buffer_line_count(0)')
+    eq('Vim(call):E117: Unknown function: buffer_line_count', err)
+
+    -- Functions deprecated before the api functions became available
+    -- in vimscript are not exported.
+    err = exc_exec('call buffer_get_line(0, 1)')
+    eq('Vim(call):E117: Unknown function: buffer_get_line', err)
+
+    -- some api functions are only useful from a msgpack-rpc channel
+    err = exc_exec('call nvim_subscribe("fancyevent")')
+    eq('Vim(call):E117: Unknown function: nvim_subscribe', err)
+  end)
+
+  it('have metadata accessible with api_info()', function()
+    local api_keys = eval("sort(keys(api_info()))")
+    eq({'error_types', 'functions', 'types',
+        'ui_events', 'ui_options', 'version'}, api_keys)
+  end)
+
+  it('are highlighted by vim.vim syntax file', function()
+    if lfs.attributes("build/runtime/syntax/vim/generated.vim",'uid') == nil then
+      pending("runtime was not built, skipping test")
+      return
+    end
+    local screen = Screen.new(40, 8)
+    screen:attach()
+    screen:set_default_attr_ids({
+      [1] = {bold = true, foreground = Screen.colors.Brown},
+      [2] = {foreground = Screen.colors.DarkCyan},
+      [3] = {foreground = Screen.colors.SlateBlue},
+      [4] = {foreground = Screen.colors.Fuchsia},
+      [5] = {bold = true, foreground = Screen.colors.Blue},
+    })
+
+    command("set ft=vim")
+    command("let &rtp='build/runtime/,'.&rtp")
+    command("syntax on")
+    insert([[
+      call bufnr('%')
+      call nvim_input('typing...')
+      call not_a_function(42)]])
+
+    screen:expect([[
+      {1:call} {2:bufnr}{3:(}{4:'%'}{3:)}                         |
+      {1:call} {2:nvim_input}{3:(}{4:'typing...'}{3:)}            |
+      {1:call} not_a_function{3:(}{4:42}{3:^)}                 |
+      {5:~                                       }|
+      {5:~                                       }|
+      {5:~                                       }|
+      {5:~                                       }|
+                                              |
+    ]])
+  end)
+
+  it('cannot be called from sandbox', function()
+    eq('Vim(call):E48: Not allowed in sandbox',
+       pcall_err(command, "sandbox call nvim_input('ievil')"))
+    eq({''}, meths.buf_get_lines(0, 0, -1, true))
+  end)
+
+  it('converts blobs to API strings', function()
+    command('let g:v1 = nvim__id(0z68656c6c6f)')
+    command('let g:v2 = nvim__id(v:_null_blob)')
+    eq(1, eval('type(g:v1)'))
+    eq(1, eval('type(g:v2)'))
+    eq('hello', eval('g:v1'))
+    eq('', eval('g:v2'))
+  end)
+end)
diff --git a/test/functional/vimscript/buf_functions_spec.lua b/test/functional/vimscript/buf_functions_spec.lua
new file mode 100644
index 0000000000..e957e5f5af
--- /dev/null
+++ b/test/functional/vimscript/buf_functions_spec.lua
@@ -0,0 +1,306 @@
+local helpers = require('test.functional.helpers')(after_each)
+
+local lfs = require('lfs')
+
+local eq = helpers.eq
+local clear = helpers.clear
+local funcs = helpers.funcs
+local meths = helpers.meths
+local command = helpers.command
+local exc_exec = helpers.exc_exec
+local bufmeths = helpers.bufmeths
+local winmeths = helpers.winmeths
+local curbufmeths = helpers.curbufmeths
+local curwinmeths = helpers.curwinmeths
+local curtabmeths = helpers.curtabmeths
+local get_pathsep = helpers.get_pathsep
+local rmdir = helpers.rmdir
+local pcall_err = helpers.pcall_err
+
+local fname = 'Xtest-functional-eval-buf_functions'
+local fname2 = fname .. '.2'
+local dirname = fname .. '.d'
+
+before_each(clear)
+
+for _, func in ipairs({'bufname(%s)', 'bufnr(%s)', 'bufwinnr(%s)',
+                       'getbufline(%s, 1)', 'getbufvar(%s, "changedtick")',
+                       'setbufvar(%s, "f", 0)'}) do
+  local funcname = func:match('%w+')
+  describe(funcname .. '() function', function()
+    it('errors out when receives v:true/v:false/v:null', function()
+      -- Not compatible with Vim: in Vim it always results in buffer not found
+      -- without any error messages.
+      for _, var in ipairs({'v:true', 'v:false'}) do
+        eq('Vim(call):E5299: Expected a Number or a String, Boolean found',
+           exc_exec('call ' .. func:format(var)))
+      end
+      eq('Vim(call):E5300: Expected a Number or a String',
+         exc_exec('call ' .. func:format('v:null')))
+    end)
+    it('errors out when receives invalid argument', function()
+      eq('Vim(call):E745: Expected a Number or a String, List found',
+         exc_exec('call ' .. func:format('[]')))
+      eq('Vim(call):E728: Expected a Number or a String, Dictionary found',
+         exc_exec('call ' .. func:format('{}')))
+      eq('Vim(call):E805: Expected a Number or a String, Float found',
+         exc_exec('call ' .. func:format('0.0')))
+      eq('Vim(call):E703: Expected a Number or a String, Funcref found',
+         exc_exec('call ' .. func:format('function("tr")')))
+    end)
+  end)
+end
+
+describe('bufname() function', function()
+  it('returns empty string when buffer was not found', function()
+    command('file ' .. fname)
+    eq('', funcs.bufname(2))
+    eq('', funcs.bufname('non-existent-buffer'))
+    eq('', funcs.bufname('#'))
+    command('edit ' .. fname2)
+    eq(2, funcs.bufnr('%'))
+    eq('', funcs.bufname('X'))
+  end)
+  before_each(function()
+    lfs.mkdir(dirname)
+  end)
+  after_each(function()
+    rmdir(dirname)
+  end)
+  it('returns expected buffer name', function()
+    eq('', funcs.bufname('%'))  -- Buffer has no name yet
+    command('file ' .. fname)
+    local wd = lfs.currentdir()
+    local sep = get_pathsep()
+    local curdirname = funcs.fnamemodify(wd, ':t')
+    for _, arg in ipairs({'%', 1, 'X', wd}) do
+      eq(fname, funcs.bufname(arg))
+      meths.set_current_dir('..')
+      eq(curdirname .. sep .. fname, funcs.bufname(arg))
+      meths.set_current_dir(curdirname)
+      meths.set_current_dir(dirname)
+      eq(wd .. sep .. fname, funcs.bufname(arg))
+      meths.set_current_dir('..')
+      eq(fname, funcs.bufname(arg))
+      command('enew')
+    end
+    eq('', funcs.bufname('%'))
+    eq('', funcs.bufname('$'))
+    eq(2, funcs.bufnr('%'))
+  end)
+end)
+
+describe('bufnr() function', function()
+  it('returns -1 when buffer was not found', function()
+    command('file ' .. fname)
+    eq(-1, funcs.bufnr(2))
+    eq(-1, funcs.bufnr('non-existent-buffer'))
+    eq(-1, funcs.bufnr('#'))
+    command('edit ' .. fname2)
+    eq(2, funcs.bufnr('%'))
+    eq(-1, funcs.bufnr('X'))
+  end)
+  it('returns expected buffer number', function()
+    eq(1, funcs.bufnr('%'))
+    command('file ' .. fname)
+    local wd = lfs.currentdir()
+    local curdirname = funcs.fnamemodify(wd, ':t')
+    eq(1, funcs.bufnr(fname))
+    eq(1, funcs.bufnr(wd))
+    eq(1, funcs.bufnr(curdirname))
+    eq(1, funcs.bufnr('X'))
+  end)
+  it('returns number of last buffer with "$"', function()
+    eq(1, funcs.bufnr('$'))
+    command('new')
+    eq(2, funcs.bufnr('$'))
+    command('new')
+    eq(3, funcs.bufnr('$'))
+    command('only')
+    eq(3, funcs.bufnr('$'))
+    eq(3, funcs.bufnr('%'))
+    command('buffer 1')
+    eq(3, funcs.bufnr('$'))
+    eq(1, funcs.bufnr('%'))
+    command('bwipeout 2')
+    eq(3, funcs.bufnr('$'))
+    eq(1, funcs.bufnr('%'))
+    command('bwipeout 3')
+    eq(1, funcs.bufnr('$'))
+    eq(1, funcs.bufnr('%'))
+    command('new')
+    eq(4, funcs.bufnr('$'))
+  end)
+end)
+
+describe('bufwinnr() function', function()
+  it('returns -1 when buffer was not found', function()
+    command('file ' .. fname)
+    eq(-1, funcs.bufwinnr(2))
+    eq(-1, funcs.bufwinnr('non-existent-buffer'))
+    eq(-1, funcs.bufwinnr('#'))
+    command('split ' .. fname2)  -- It would be OK if there was one window
+    eq(2, funcs.bufnr('%'))
+    eq(-1, funcs.bufwinnr('X'))
+  end)
+  before_each(function()
+    lfs.mkdir(dirname)
+  end)
+  after_each(function()
+    rmdir(dirname)
+  end)
+  it('returns expected window number', function()
+    eq(1, funcs.bufwinnr('%'))
+    command('file ' .. fname)
+    command('vsplit')
+    command('split ' .. fname2)
+    eq(2, funcs.bufwinnr(fname))
+    eq(1, funcs.bufwinnr(fname2))
+    eq(-1, funcs.bufwinnr(fname:sub(1, #fname - 1)))
+    meths.set_current_dir(dirname)
+    eq(2, funcs.bufwinnr(fname))
+    eq(1, funcs.bufwinnr(fname2))
+    eq(-1, funcs.bufwinnr(fname:sub(1, #fname - 1)))
+    eq(1, funcs.bufwinnr('%'))
+    eq(2, funcs.bufwinnr(1))
+    eq(1, funcs.bufwinnr(2))
+    eq(-1, funcs.bufwinnr(3))
+    eq(1, funcs.bufwinnr('$'))
+  end)
+end)
+
+describe('getbufline() function', function()
+  it('returns empty list when buffer was not found', function()
+    command('file ' .. fname)
+    eq({}, funcs.getbufline(2, 1))
+    eq({}, funcs.getbufline('non-existent-buffer', 1))
+    eq({}, funcs.getbufline('#', 1))
+    command('edit ' .. fname2)
+    eq(2, funcs.bufnr('%'))
+    eq({}, funcs.getbufline('X', 1))
+  end)
+  it('returns empty list when range is invalid', function()
+    eq({}, funcs.getbufline(1, 0))
+    curbufmeths.set_lines(0, 1, false, {'foo', 'bar', 'baz'})
+    eq({}, funcs.getbufline(1, 2, 1))
+    eq({}, funcs.getbufline(1, -10, -20))
+    eq({}, funcs.getbufline(1, -2, -1))
+    eq({}, funcs.getbufline(1, -1, 9999))
+  end)
+  it('returns expected lines', function()
+    meths.set_option('hidden', true)
+    command('file ' .. fname)
+    curbufmeths.set_lines(0, 1, false, {'foo\0', '\0bar', 'baz'})
+    command('edit ' .. fname2)
+    curbufmeths.set_lines(0, 1, false, {'abc\0', '\0def', 'ghi'})
+    eq({'foo\n', '\nbar', 'baz'}, funcs.getbufline(1, 1, 9999))
+    eq({'abc\n', '\ndef', 'ghi'}, funcs.getbufline(2, 1, 9999))
+    eq({'foo\n', '\nbar', 'baz'}, funcs.getbufline(1, 1, '$'))
+    eq({'baz'}, funcs.getbufline(1, '$', '$'))
+    eq({'baz'}, funcs.getbufline(1, '$', 9999))
+  end)
+end)
+
+describe('getbufvar() function', function()
+  it('returns empty list when buffer was not found', function()
+    command('file ' .. fname)
+    eq('', funcs.getbufvar(2, '&autoindent'))
+    eq('', funcs.getbufvar('non-existent-buffer', '&autoindent'))
+    eq('', funcs.getbufvar('#', '&autoindent'))
+    command('edit ' .. fname2)
+    eq(2, funcs.bufnr('%'))
+    eq('', funcs.getbufvar('X', '&autoindent'))
+  end)
+  it('returns empty list when variable/option/etc was not found', function()
+    command('file ' .. fname)
+    eq('', funcs.getbufvar(1, '&autondent'))
+    eq('', funcs.getbufvar(1, 'changedtic'))
+  end)
+  it('returns expected option value', function()
+    eq(0, funcs.getbufvar(1, '&autoindent'))
+    eq(0, funcs.getbufvar(1, '&l:autoindent'))
+    eq(0, funcs.getbufvar(1, '&g:autoindent'))
+    -- Also works with global-only options
+    eq(1, funcs.getbufvar(1, '&hidden'))
+    eq(1, funcs.getbufvar(1, '&l:hidden'))
+    eq(1, funcs.getbufvar(1, '&g:hidden'))
+    -- Also works with window-local options
+    eq(0, funcs.getbufvar(1, '&number'))
+    eq(0, funcs.getbufvar(1, '&l:number'))
+    eq(0, funcs.getbufvar(1, '&g:number'))
+    command('new')
+    -- But with window-local options it probably does not what you expect
+    command("setl number")
+    -- (note that current window’s buffer is 2, but getbufvar() receives 1)
+    eq({id=2}, curwinmeths.get_buf())
+    eq(1, funcs.getbufvar(1, '&number'))
+    eq(1, funcs.getbufvar(1, '&l:number'))
+    -- You can get global value though, if you find this useful.
+    eq(0, funcs.getbufvar(1, '&g:number'))
+  end)
+  it('returns expected variable value', function()
+    eq(2, funcs.getbufvar(1, 'changedtick'))
+    curbufmeths.set_lines(0, 1, false, {'abc\0', '\0def', 'ghi'})
+    eq(3, funcs.getbufvar(1, 'changedtick'))
+    curbufmeths.set_var('test', true)
+    eq(true, funcs.getbufvar(1, 'test'))
+    eq({test=true, changedtick=3}, funcs.getbufvar(1, ''))
+    command('new')
+    eq(3, funcs.getbufvar(1, 'changedtick'))
+    eq(true, funcs.getbufvar(1, 'test'))
+    eq({test=true, changedtick=3}, funcs.getbufvar(1, ''))
+  end)
+end)
+
+describe('setbufvar() function', function()
+  it('throws the error or ignores the input when buffer was not found', function()
+    command('file ' .. fname)
+    eq(0,
+       exc_exec('call setbufvar(2, "&autoindent", 0)'))
+    eq('Vim(call):E94: No matching buffer for non-existent-buffer',
+       exc_exec('call setbufvar("non-existent-buffer", "&autoindent", 0)'))
+    eq(0,
+       exc_exec('call setbufvar("#", "&autoindent", 0)'))
+    command('edit ' .. fname2)
+    eq(2, funcs.bufnr('%'))
+    eq('Vim(call):E93: More than one match for X',
+       exc_exec('call setbufvar("X", "&autoindent", 0)'))
+  end)
+  it('may set options, including window-local and global values', function()
+    local buf1 = meths.get_current_buf()
+    eq(false, curwinmeths.get_option('number'))
+    command('split')
+    command('new')
+    eq(2, bufmeths.get_number(curwinmeths.get_buf()))
+    funcs.setbufvar(1, '&number', true)
+    local windows = curtabmeths.list_wins()
+    eq(false, winmeths.get_option(windows[1], 'number'))
+    eq(true, winmeths.get_option(windows[2], 'number'))
+    eq(false, winmeths.get_option(windows[3], 'number'))
+    eq(false, winmeths.get_option(meths.get_current_win(), 'number'))
+
+    eq(true, meths.get_option('hidden'))
+    funcs.setbufvar(1, '&hidden', 0)
+    eq(false, meths.get_option('hidden'))
+
+    eq(false, bufmeths.get_option(buf1, 'autoindent'))
+    funcs.setbufvar(1, '&autoindent', true)
+    eq(true, bufmeths.get_option(buf1, 'autoindent'))
+    eq('Vim(call):E355: Unknown option: xxx',
+       exc_exec('call setbufvar(1, "&xxx", 0)'))
+  end)
+  it('may set variables', function()
+    local buf1 = meths.get_current_buf()
+    command('split')
+    command('new')
+    eq(2, curbufmeths.get_number())
+    funcs.setbufvar(1, 'number', true)
+    eq(true, bufmeths.get_var(buf1, 'number'))
+    eq('Vim(call):E461: Illegal variable name: b:',
+       exc_exec('call setbufvar(1, "", 0)'))
+    eq(true, bufmeths.get_var(buf1, 'number'))
+    eq('Vim:E46: Cannot change read-only variable "b:changedtick"',
+      pcall_err(funcs.setbufvar, 1, 'changedtick', true))
+    eq(2, funcs.getbufvar(1, 'changedtick'))
+  end)
+end)
diff --git a/test/functional/vimscript/changedtick_spec.lua b/test/functional/vimscript/changedtick_spec.lua
new file mode 100644
index 0000000000..99406d9d7a
--- /dev/null
+++ b/test/functional/vimscript/changedtick_spec.lua
@@ -0,0 +1,142 @@
+local helpers = require('test.functional.helpers')(after_each)
+
+local eq = helpers.eq
+local eval = helpers.eval
+local feed = helpers.feed
+local clear = helpers.clear
+local funcs = helpers.funcs
+local meths = helpers.meths
+local command = helpers.command
+local exc_exec = helpers.exc_exec
+local redir_exec = helpers.redir_exec
+local pcall_err = helpers.pcall_err
+local curbufmeths = helpers.curbufmeths
+
+before_each(clear)
+
+local function changedtick()
+  local ct = curbufmeths.get_changedtick()
+  eq(ct, curbufmeths.get_var('changedtick'))
+  eq(ct, curbufmeths.get_var('changedtick'))
+  eq(ct, eval('b:changedtick'))
+  eq(ct, eval('b:["changedtick"]'))
+  eq(ct, eval('b:.changedtick'))
+  eq(ct, funcs.getbufvar('%', 'changedtick'))
+  eq(ct, funcs.getbufvar('%', '').changedtick)
+  eq(ct, eval('b:').changedtick)
+  return ct
+end
+
+describe('b:changedtick', function()
+  -- Ported tests from Vim-8.0.333
+  it('increments', function()  -- Test_changedtick_increments
+    -- New buffer has an empty line, tick starts at 2
+    eq(2, changedtick())
+    funcs.setline(1, 'hello')
+    eq(3, changedtick())
+    eq(0, exc_exec('undo'))
+    -- Somehow undo counts as two changes
+    eq(5, changedtick())
+  end)
+  it('is present in b: dictionary', function()
+    eq(2, changedtick())
+    command('let d = b:')
+    eq(2, meths.get_var('d').changedtick)
+  end)
+  it('increments at bdel', function()
+    command('new')
+    eq(2, changedtick())
+    local bnr = curbufmeths.get_number()
+    eq(2, bnr)
+    command('bdel')
+    eq(3, funcs.getbufvar(bnr, 'changedtick'))
+    eq(1, curbufmeths.get_number())
+  end)
+  it('fails to be changed by user', function()
+    local ct = changedtick()
+    local ctn = ct + 100500
+    eq(0, exc_exec('let d = b:'))
+    eq('\nE46: Cannot change read-only variable "b:changedtick"',
+       redir_exec('let b:changedtick = ' .. ctn))
+    eq('\nE46: Cannot change read-only variable "b:["changedtick"]"',
+       redir_exec('let b:["changedtick"] = ' .. ctn))
+    eq('\nE46: Cannot change read-only variable "b:.changedtick"',
+       redir_exec('let b:.changedtick = ' .. ctn))
+    eq('\nE46: Cannot change read-only variable "d.changedtick"',
+       redir_exec('let d.changedtick = ' .. ctn))
+    eq('Key is read-only: changedtick',
+      pcall_err(curbufmeths.set_var, 'changedtick', ctn))
+
+    eq('\nE795: Cannot delete variable b:changedtick',
+       redir_exec('unlet b:changedtick'))
+    eq('\nE46: Cannot change read-only variable "b:.changedtick"',
+       redir_exec('unlet b:.changedtick'))
+    eq('\nE46: Cannot change read-only variable "b:["changedtick"]"',
+       redir_exec('unlet b:["changedtick"]'))
+    eq('\nE46: Cannot change read-only variable "d.changedtick"',
+       redir_exec('unlet d.changedtick'))
+    eq('Key is read-only: changedtick',
+      pcall_err(curbufmeths.del_var, 'changedtick'))
+    eq(ct, changedtick())
+
+    eq('\nE46: Cannot change read-only variable "b:["changedtick"]"',
+       redir_exec('let b:["changedtick"] += ' .. ctn))
+    eq('\nE46: Cannot change read-only variable "b:["changedtick"]"',
+       redir_exec('let b:["changedtick"] -= ' .. ctn))
+    eq('\nE46: Cannot change read-only variable "b:["changedtick"]"',
+       redir_exec('let b:["changedtick"] .= ' .. ctn))
+
+    eq(ct, changedtick())
+
+    funcs.setline(1, 'hello')
+
+    eq(ct + 1, changedtick())
+  end)
+  it('is listed in :let output', function()
+    eq('\nb:changedtick         #2',
+       redir_exec(':let b:'))
+  end)
+  it('fails to unlock b:changedtick', function()
+    eq(0, exc_exec('let d = b:'))
+    eq(0, funcs.islocked('b:changedtick'))
+    eq(0, funcs.islocked('d.changedtick'))
+    eq('\nE940: Cannot lock or unlock variable b:changedtick',
+       redir_exec('unlockvar b:changedtick'))
+    eq('\nE46: Cannot change read-only variable "d.changedtick"',
+       redir_exec('unlockvar d.changedtick'))
+    eq(0, funcs.islocked('b:changedtick'))
+    eq(0, funcs.islocked('d.changedtick'))
+    eq('\nE940: Cannot lock or unlock variable b:changedtick',
+       redir_exec('lockvar b:changedtick'))
+    eq('\nE46: Cannot change read-only variable "d.changedtick"',
+       redir_exec('lockvar d.changedtick'))
+    eq(0, funcs.islocked('b:changedtick'))
+    eq(0, funcs.islocked('d.changedtick'))
+  end)
+  it('is being completed', function()
+    feed(':echo b:<Tab><Home>let cmdline="<End>"<CR>')
+    eq('echo b:changedtick', meths.get_var('cmdline'))
+  end)
+  it('cannot be changed by filter() or map()', function()
+    eq(2, changedtick())
+    eq('\nE795: Cannot delete variable filter() argument',
+       redir_exec('call filter(b:, 0)'))
+    eq('\nE742: Cannot change value of map() argument',
+       redir_exec('call map(b:, 0)'))
+    eq('\nE742: Cannot change value of map() argument',
+       redir_exec('call map(b:, "v:val")'))
+    eq(2, changedtick())
+  end)
+  it('cannot be remove()d', function()
+    eq(2, changedtick())
+    eq('\nE795: Cannot delete variable remove() argument',
+       redir_exec('call remove(b:, "changedtick")'))
+    eq(2, changedtick())
+  end)
+  it('does not inherit VAR_FIXED when copying dictionary over', function()
+    eq(2, changedtick())
+    eq('', redir_exec('let d1 = copy(b:)|let d1.changedtick = 42'))
+    eq('', redir_exec('let d2 = copy(b:)|unlet d2.changedtick'))
+    eq(2, changedtick())
+  end)
+end)
diff --git a/test/functional/vimscript/container_functions_spec.lua b/test/functional/vimscript/container_functions_spec.lua
new file mode 100644
index 0000000000..04a3248c49
--- /dev/null
+++ b/test/functional/vimscript/container_functi