test(harness): migrate away from magic globals

Problem:
The magic globals `it`, `describe`, etc., are more trouble than they are
worth.

- Hooking into `after_each` requires `getfenv()` hacks.
- They confuse luals/emmylua, because the top-level `.luarc.json` isn't
  merged with `test/.luarc.json` (apparently a luals limitation?)
- They totally defeat discoverability because the user just has to
  "know" about the various magic symbols.

So they harm DX, which means they serve no purpose at all.

Solution:
- Expose the test API from `testutil`, so tests can call `t.it()`,
  `t.describe()`, etc., in the conventional way.
- Drop `getfenv()` hacks.
- Drop the `setfenv()` injection in `load_chunk`.
- Drop `test/_meta.lua`.

test/functional/vimscript/api_functions_spec.lua

@@ -2,6 +2,7 @@ local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 local Screen = require('test.functional.ui.screen')
 
+local describe, it, before_each = t.describe, t.it, t.before_each
 local neq, eq, command = t.neq, t.eq, n.command
 local clear = n.clear
 local expect, eval = n.expect, n.eval

test/functional/vimscript/buf_functions_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, before_each, after_each = t.describe, t.it, t.before_each, t.after_each
 local eq = t.eq
 local clear = n.clear
 local fn = n.fn

test/functional/vimscript/changedtick_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, before_each = t.describe, t.it, t.before_each
 local eq = t.eq
 local eval = n.eval
 local feed = n.feed

test/functional/vimscript/container_functions_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, before_each = t.describe, t.it, t.before_each
 local eq = t.eq
 local eval = n.eval
 local api = n.api

test/functional/vimscript/environ_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, before_each, after_each = t.describe, t.it, t.before_each, t.after_each
 local clear = n.clear
 local eq = t.eq
 local environ = n.fn.environ

test/functional/vimscript/errorlist_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, before_each = t.describe, t.it, t.before_each
 local clear = n.clear
 local command = n.command
 local eq = t.eq

test/functional/vimscript/eval_spec.lua

@@ -13,6 +13,8 @@ local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 local Screen = require('test.functional.ui.screen')
 
+local describe, it, before_each, setup, teardown, pending, finally =
+  t.describe, t.it, t.before_each, t.setup, t.teardown, t.pending, t.finally
 local mkdir = t.mkdir
 local pcall_err = t.pcall_err
 local clear = n.clear

test/functional/vimscript/executable_spec.lua

@@ -1,6 +1,8 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, before_each, setup, teardown, pending =
+  t.describe, t.it, t.before_each, t.setup, t.teardown, t.pending
 local eq, clear, call, write_file, command = t.eq, n.clear, n.call, t.write_file, n.command
 local eval, fn = n.eval, n.fn
 local is_os = t.is_os

test/functional/vimscript/execute_spec.lua

@@ -2,6 +2,7 @@ local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 local Screen = require('test.functional.ui.screen')
 
+local describe, it, before_each = t.describe, t.it, t.before_each
 local eq = t.eq
 local eval = n.eval
 local clear = n.clear

test/functional/vimscript/exepath_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, before_each = t.describe, t.it, t.before_each
 local eq, clear, call = t.eq, n.clear, n.call
 local command = n.command
 local matches = t.matches

test/functional/vimscript/fnamemodify_spec.lua

@@ -1,6 +1,8 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, before_each, setup, teardown =
+  t.describe, t.it, t.before_each, t.setup, t.teardown
 local clear = n.clear
 local eq = t.eq
 local exec_lua = n.exec_lua

test/functional/vimscript/functions_spec.lua

@@ -8,6 +8,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local it, before_each = t.it, t.before_each
 local clear = n.clear
 local eval = n.eval
 local matches = t.matches

test/functional/vimscript/getchar_spec.lua

@@ -1,6 +1,8 @@
 local n = require('test.functional.testnvim')()
+local t = require('test.testutil')
 local Screen = require('test.functional.ui.screen')
 
+local describe, it, before_each = t.describe, t.it, t.before_each
 local clear = n.clear
 local exec = n.exec
 local feed = n.feed

test/functional/vimscript/getline_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, before_each = t.describe, t.it, t.before_each
 local call = n.call
 local clear = n.clear
 local eq = t.eq

test/functional/vimscript/glob_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, before_each, after_each = t.describe, t.it, t.before_each, t.after_each
 local clear, command, eval, eq = n.clear, n.command, n.eval, t.eq
 local mkdir = t.mkdir
 

test/functional/vimscript/has_spec.lua

@@ -2,6 +2,7 @@ local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 local Screen = require('test.functional.ui.screen')
 
+local describe, it, before_each, pending = t.describe, t.it, t.before_each, t.pending
 local clear = n.clear
 local connect = n.connect
 local get_session = n.get_session

test/functional/vimscript/hostname_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, before_each = t.describe, t.it, t.before_each
 local eq = t.eq
 local ok = t.ok
 local call = n.call

test/functional/vimscript/input_spec.lua

@@ -2,6 +2,7 @@ local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 local Screen = require('test.functional.ui.screen')
 
+local describe, it, before_each = t.describe, t.it, t.before_each
 local eq = t.eq
 local pcall_err = t.pcall_err
 local feed = n.feed

test/functional/vimscript/json_functions_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, setup = t.describe, t.it, t.setup
 local clear = n.clear
 local fn = n.fn
 local api = n.api

test/functional/vimscript/lang_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, before_each, pending = t.describe, t.it, t.before_each, t.pending
 local clear, eval, eq = n.clear, n.eval, t.eq
 local source = n.source
 

test/functional/vimscript/let_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, before_each = t.describe, t.it, t.before_each
 local eq = t.eq
 local clear = n.clear
 local command = n.command

test/functional/vimscript/map_functions_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, before_each = t.describe, t.it, t.before_each
 local clear = n.clear
 local eq = t.eq
 local eval = n.eval

test/functional/vimscript/match_functions_spec.lua

@@ -2,6 +2,7 @@ local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 local Screen = require('test.functional.ui.screen')
 
+local describe, it, before_each = t.describe, t.it, t.before_each
 local eq = t.eq
 local pcall_err = t.pcall_err
 local clear = n.clear

test/functional/vimscript/minmax_functions_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, setup = t.describe, t.it, t.setup
 local eq = t.eq
 local eval = n.eval
 local command = n.command

test/functional/vimscript/modeline_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, before_each, after_each = t.describe, t.it, t.before_each, t.after_each
 local assert_alive = n.assert_alive
 local clear, command, write_file = n.clear, n.command, t.write_file
 

test/functional/vimscript/msgpack_functions_spec.lua

@@ -1,4 +1,5 @@
 local t = require('test.testutil')
+local describe, it, setup = t.describe, t.it, t.setup
 local pcall_err = t.pcall_err
 local n = require('test.functional.testnvim')()
 

test/functional/vimscript/null_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, before_each, after_each = t.describe, t.it, t.before_each, t.after_each
 local command = n.command
 local clear = n.clear
 local api = n.api

test/functional/vimscript/operators_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, setup = t.describe, t.it, t.setup
 local eq = t.eq
 local eval = n.eval
 local clear = n.clear

test/functional/vimscript/printf_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, setup = t.describe, t.it, t.setup
 local clear = n.clear
 local eq = t.eq
 local pcall_err = t.pcall_err

test/functional/vimscript/reltime_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, before_each = t.describe, t.it, t.before_each
 local clear, eq, ok = n.clear, t.eq, t.ok
 local neq, command, fn = t.neq, n.command, n.fn
 local matches = t.matches

test/functional/vimscript/screenchar_spec.lua

@@ -2,6 +2,7 @@ local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 local Screen = require('test.functional.ui.screen')
 
+local describe, it, before_each, setup = t.describe, t.it, t.before_each, t.setup
 local clear, eq, neq = n.clear, t.eq, t.neq
 local command, api, fn = n.command, n.api, n.fn
 local tbl_deep_extend = vim.tbl_deep_extend

test/functional/vimscript/screenpos_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, before_each = t.describe, t.it, t.before_each
 local clear, eq, api = n.clear, t.eq, n.api
 local command, fn = n.command, n.fn
 local feed = n.feed

test/functional/vimscript/screenrowcol_spec.lua

@@ -2,6 +2,7 @@ local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 local Screen = require('test.functional.ui.screen')
 
+local describe, before_each, pending = t.describe, t.before_each, t.pending
 local clear, eq, api = n.clear, t.eq, n.api
 local command, fn = n.command, n.fn
 local feed = n.feed

test/functional/vimscript/setpos_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, before_each = t.describe, t.it, t.before_each
 local setpos = n.fn.setpos
 local getpos = n.fn.getpos
 local insert = n.insert

test/functional/vimscript/sort_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, setup = t.describe, t.it, t.setup
 local eq = t.eq
 local NIL = vim.NIL
 local eval = n.eval

test/functional/vimscript/special_vars_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, before_each = t.describe, t.it, t.before_each
 local command = n.command
 local fn = n.fn
 local clear = n.clear

test/functional/vimscript/state_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, before_each = t.describe, t.it, t.before_each
 local clear = n.clear
 local eq = t.eq
 local exec = n.exec

test/functional/vimscript/string_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, setup = t.describe, t.it, t.setup
 local clear = n.clear
 local eq = t.eq
 local command = n.command

test/functional/vimscript/system_spec.lua

@@ -4,6 +4,8 @@ local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 local Screen = require('test.functional.ui.screen')
 
+local describe, it, before_each, after_each, pending, finally =
+  t.describe, t.it, t.before_each, t.after_each, t.pending, t.finally
 local assert_alive = n.assert_alive
 local testprg = n.testprg
 local eq, call, clear, eval, feed_command, feed, api =

test/functional/vimscript/timer_spec.lua

@@ -2,6 +2,7 @@ local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 local Screen = require('test.functional.ui.screen')
 
+local describe, it, before_each = t.describe, t.it, t.before_each
 local feed, eq, eval, ok = n.feed, t.eq, n.eval, t.ok
 local source, async_meths, run = n.source, n.async_meths, n.run
 local clear, command, fn = n.clear, n.command, n.fn

test/functional/vimscript/uniq_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, setup = t.describe, t.it, t.setup
 local eq = t.eq
 local clear = n.clear
 local command = n.command

test/functional/vimscript/vvars_spec.lua

@@ -1,4 +1,5 @@
 local t = require('test.testutil')
+local describe, it, before_each = t.describe, t.it, t.before_each
 local pcall_err = t.pcall_err
 local n = require('test.functional.testnvim')()
 

test/functional/vimscript/wait_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, before_each = t.describe, t.it, t.before_each
 local call = n.call
 local clear = n.clear
 local command = n.command

test/functional/vimscript/writefile_spec.lua

@@ -1,6 +1,7 @@
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
 
+local describe, it, before_each, after_each = t.describe, t.it, t.before_each, t.after_each
 local mkdir = t.mkdir
 local clear = n.clear
 local eq = t.eq