refactor(test): make helper test function more ergonomic

In my opinion, requiring user to access tests via `T["module_name"]`
was too fragile and typos prone.

spec/integration/comment_test.lua

···
 local t = require "spec.testutils"
-local child, T = t.setup "comment"
+local child, T, comment = t.setup "comment"
 
 local function do_the_test(fixture, pos)
   local rs = t.setup_test("comment/" .. fixture, child, pos)
···
   t.cleanup(rs)
 end
 
-T["comment"]["should add comment to package"] = function()
+comment["should add comment to package"] = function()
   do_the_test("package", { 1, 1 })
 end
 
-T["comment"]["should add comment to struct"] = function()
+comment["should add comment to struct"] = function()
   do_the_test("struct", { 4, 1 })
 end
 
-T["comment"]["should add comment to function"] = function()
+comment["should add comment to function"] = function()
   do_the_test("func", { 3, 1 })
 end
 
-T["comment"]["should add comment to method"] = function()
+comment["should add comment to method"] = function()
   do_the_test("method", { 5, 1 })
 end
 
-T["comment"]["should add comment to interface"] = function()
+comment["should add comment to interface"] = function()
   do_the_test("interface", { 3, 6 })
 end
 
-T["comment"]["otherwise should add // above cursor"] = function()
+comment["otherwise should add // above cursor"] = function()
   do_the_test("empty", { 1, 1 })
 end
 

spec/integration/gotests_test.lua

···
 local t = require "spec.testutils"
-local child, T = t.setup "gotests"
+local child, T, gotests = t.setup "gotests"
 
 --- NOTE: :GoTestAdd is the only place that has actual logic
 --- All other parts are handled `gotests` itself.
···
   return t.readfile(fpath:gsub(".go", "_test.go"))
 end
 
-T["gotests"]["should add test for function under cursor"] = function()
+gotests["should add test for function under cursor"] = function()
   local rs = t.setup_test("tests/function", child, { 3, 5 })
   child.cmd "GoTestAdd"
 
···
   t.cleanup(rs)
 end
 
-T["gotests"]["should add test for method under cursor"] = function()
+gotests["should add test for method under cursor"] = function()
   local rs = t.setup_test("tests/method", child, { 5, 19 })
   child.cmd "GoTestAdd"
 

spec/integration/iferr_test.lua

···
 local t = require "spec.testutils"
-local child, T = t.setup "iferr"
+local child, T, iferr = t.setup "iferr"
 
-T["iferr"]["should add if != nil {"] = function()
+iferr["should add if != nil {"] = function()
   local rs = t.setup_test("iferr/iferr", child, { 8, 2 })
   child.cmd "GoIfErr"
   child.cmd "write"
···
   t.cleanup(rs)
 end
 
-T["iferr"]["should add if err with custom message"] = function()
+iferr["should add if err with custom message"] = function()
   child.lua [[
     require("gopher").setup {
       iferr = { message = 'fmt.Errorf("failed to %w", err)' }

spec/integration/impl_test.lua

···
 local t = require "spec.testutils"
-local child, T = t.setup "impl"
+local child, T, impl = t.setup "impl"
 
-T["impl"]["should do impl with 'w io.Writer'"] = function()
+impl["should do impl with 'w io.Writer'"] = function()
   local rs = t.setup_test("impl/writer", child, { 3, 0 })
   child.cmd "GoImpl w io.Writer"
   child.cmd "write"
···
   t.cleanup(rs)
 end
 
-T["impl"]["should work with full input, 'r Read io.Reader'"] = function()
+impl["should work with full input, 'r Read io.Reader'"] = function()
   local rs = t.setup_test("impl/reader", child)
   child.cmd "GoImpl r Read io.Reader"
   child.cmd "write"
···
   t.cleanup(rs)
 end
 
-T["impl"]["should work with minimal input 'io.Closer'"] = function()
+impl["should work with minimal input 'io.Closer'"] = function()
   local rs = t.setup_test("impl/closer", child, { 3, 6 })
   child.cmd "GoImpl io.Closer"
   child.cmd "write"

spec/integration/struct_tags_test.lua

···
 local t = require "spec.testutils"
-local child, T = t.setup "struct_tags"
+local child, T, struct_tags = t.setup "struct_tags"
 
-T["struct_tags"]["should add tag"] = function()
+struct_tags["should add tag"] = function()
   local rs = t.setup_test("tags/add", child, { 3, 6 })
   child.cmd "GoTagAdd json"
   child.cmd "write"
···
   t.cleanup(rs)
 end
 
-T["struct_tags"]["should remove tag"] = function()
+struct_tags["should remove tag"] = function()
   local rs = t.setup_test("tags/remove", child, { 4, 6 })
   child.cmd "GoTagRm json"
   child.cmd "write"
···
   t.cleanup(rs)
 end
 
-T["struct_tags"]["should be able to handle many structs"] = function()
+struct_tags["should be able to handle many structs"] = function()
   local rs = t.setup_test("tags/many", child, { 10, 3 })
   child.cmd "GoTagAdd testing"
   child.cmd "write"
···
   t.cleanup(rs)
 end
 
-T["struct_tags"]["should clear struct"] = function()
+struct_tags["should clear struct"] = function()
   local rs = t.setup_test("tags/clear", child, { 3, 1 })
   child.cmd "GoTagClear"
   child.cmd "write"
···
   t.cleanup(rs)
 end
 
-T["struct_tags"]["should add more than one tag"] = function()
+struct_tags["should add more than one tag"] = function()
   local tmp = t.tmpfile()
   local fixtures = t.get_fixtures "tags/add_many"
   t.writefile(tmp, fixtures.input)
···
   t.cleanup { tmp = tmp }
 end
 
-T["struct_tags"]["should add tags on var"] = function()
+struct_tags["should add tags on var"] = function()
   local rs = t.setup_test("tags/var", child, { 5, 6 })
   child.cmd "GoTagAdd yaml"
   child.cmd "write"
···
   t.cleanup(rs)
 end
 
-T["struct_tags"]["should add tags on short declr var"] = function()
+struct_tags["should add tags on short declr var"] = function()
   local rs = t.setup_test("tags/svar", child, { 4, 3 })
   child.cmd "GoTagAdd xml"
   child.cmd "write"

spec/testutils.lua

···
 testutils.mininit_path = vim.fs.joinpath(base_dir, "scripts", "minimal_init.lua")
 testutils.fixtures_dir = vim.fs.joinpath(base_dir, "spec/fixtures")
 
----@param name string
----@return MiniTest.child, table
-function testutils.setup(name)
+---@param mod string Module name for which to create a nested test set.
+---@return MiniTest.child child nvim client.
+---@return table T root test set created by `MiniTest.new_set()`.
+---@return table mod_name nested set of tests in `T[mod]`.
+function testutils.setup(mod)
   local child = MiniTest.new_child_neovim()
   local T = MiniTest.new_set {
     hooks = {
···
     },
   }
 
-  T[name] = MiniTest.new_set {}
-  return child, T
+  T[mod] = MiniTest.new_set {}
+  return child, T, T[mod]
 end
 
 ---@generic T

spec/unit/config_test.lua

···
 local t = require "spec.testutils"
-local _, T = t.setup "config"
+local _, T, config = t.setup "config"
 
-T["config"]["can be called without any arguments passed"] = function()
+config["can be called without any arguments passed"] = function()
   ---@diagnostic disable-next-line: missing-parameter
   require("gopher").setup()
 end
 
-T["config"]["can be called with empty table"] = function()
+config["can be called with empty table"] = function()
   require("gopher").setup {}
 end
 
-T["config"]["should change option"] = function()
+config["should change option"] = function()
   local log_level = 1234567890
   require("gopher").setup {
     log_level = log_level,

spec/unit/utils_test.lua

···
 local t = require "spec.testutils"
-local _, T = t.setup "utils"
+local _, T, utils = t.setup "utils"
 
-T["utils"]["should .remove_empty_lines()"] = function()
+utils["should .remove_empty_lines()"] = function()
   local u = require "gopher._utils"
   local inp = { "hi", "", "a", "", "", "asdf" }
 
   t.eq(u.remove_empty_lines(inp), { "hi", "a", "asdf" })
 end
 
-T["utils"]["should .readfile_joined()"] = function()
+utils["should .readfile_joined()"] = function()
   local data = "line1\nline2\nline3"
   local tmp = t.tmpfile()
   local u = require "gopher._utils"
···
   t.eq(u.readfile_joined(tmp), data)
 end
 
-T["utils"]["should .trimend()"] = function()
+utils["should .trimend()"] = function()
   local u = require "gopher._utils"
   t.eq(u.trimend "  hi   ", "  hi")
 end