fix(test): resolve busted migration test isolation issues (#25)

* fix(test): resolve busted migration test isolation issues

Problem: Two issues introduced during the plenary-to-busted migration
(6be0148). First, altbuf_spec waited for two BufEnter events but
oil:// → file resolution only fires one async BufEnter (the synchronous
one from vim.cmd.edit fires before wait_for_autocmd is registered).
Second, reset_editor kept the first window which could be a preview
window with stale oil_preview/oil_source_win state, causing
close_preview_window_if_not_in_oil to close the wrong window in
subsequent tests.

Solution: Wait for a single BufEnter in the altbuf test. Replace the
window-keeping logic in reset_editor with vim.cmd.new() +
vim.cmd.only() to guarantee a fresh window with no inherited state.
This also fixes the preview_spec.lua:30 timeout which had the same
root cause. 114/114 tests pass.

* fix(ci): fix nightly tests and remove unused Makefile

Problem: Neovim nightly's ftplugin/markdown.lua now calls
vim.treesitter.start() unconditionally, which crashes in CI where the
markdown parser is not installed. The Makefile is unused — CI runs
selene, stylua, and nvim-busted-action directly.

Solution: Change filetype plugin indent on to filetype on in
minimal_init.lua. Tests only need filetype detection for
vim.bo.filetype assertions, not ftplugin or indent loading. Remove
the Makefile.

Makefile

@@ -1,44 +0,0 @@
-## help: print this help message
-.PHONY: help
-help:
-	@echo 'Usage:'
-	@sed -n 's/^##//p' ${MAKEFILE_LIST} | column -t -s ':' |  sed -e 's/^/ /'
-
-## all: lint and run tests
-.PHONY: all
-all: lint test
-
-## test: run tests
-.PHONY: test
-test:
-	luarocks test --local
-
-## lint: run selene and stylua
-.PHONY: lint
-lint:
-	selene --display-style quiet .
-	stylua --check lua spec
-
-## profile: use LuaJIT profiler to profile the plugin
-.PHONY: profile
-profile: scripts/benchmark.nvim
-	nvim --clean -u perf/bootstrap.lua -c 'lua jit_profile()'
-
-## flame_profile: create a trace in the chrome profiler format
-.PHONY: flame_profile
-flame_profile: scripts/benchmark.nvim
-	nvim --clean -u perf/bootstrap.lua -c 'lua flame_profile()'
-
-## benchmark: benchmark performance opening directory with many files
-.PHONY: benchmark
-benchmark: scripts/benchmark.nvim
-	nvim --clean -u perf/bootstrap.lua -c 'lua benchmark()'
-	@cat perf/tmp/benchmark.txt
-
-scripts/benchmark.nvim:
-	git clone https://github.com/stevearc/benchmark.nvim scripts/benchmark.nvim
-
-## clean: reset the repository to a clean state
-.PHONY: clean
-clean:
-	rm -rf perf/tmp profile.json

spec/altbuf_spec.lua

@@ -22,7 +22,6 @@ describe('Alternate buffer', function()
     local readme = fs.join(vim.fn.getcwd(), 'README.md')
     vim.cmd.edit({ args = { 'oil://' .. fs.os_to_posix_path(readme) } })
     test_util.wait_for_autocmd('BufEnter')
-    test_util.wait_for_autocmd('BufEnter')
     assert.equals(readme, vim.api.nvim_buf_get_name(0))
     assert.equals('foo', vim.fn.expand('#'))
   end)

spec/minimal_init.lua

@@ -2,7 +2,7 @@ vim.cmd([[set runtimepath=$VIMRUNTIME]])
 vim.opt.runtimepath:append('.')
 vim.opt.packpath = {}
 vim.o.swapfile = false
-vim.cmd('filetype plugin indent on')
+vim.cmd('filetype on')
 vim.fn.mkdir(vim.fn.stdpath('cache'), 'p')
 vim.fn.mkdir(vim.fn.stdpath('data'), 'p')
 vim.fn.mkdir(vim.fn.stdpath('state'), 'p')

spec/test_util.lua

@@ -12,12 +12,8 @@ M.reset_editor = function()
     prompt_save_on_select_new_entry = false,
   })
   vim.cmd.tabonly({ mods = { silent = true } })
-  for i, winid in ipairs(vim.api.nvim_tabpage_list_wins(0)) do
-    if i > 1 then
-      vim.api.nvim_win_close(winid, true)
-    end
-  end
-  vim.api.nvim_win_set_buf(0, vim.api.nvim_create_buf(false, true))
+  vim.cmd.new()
+  vim.cmd.only()
   for _, bufnr in ipairs(vim.api.nvim_list_bufs()) do
     vim.api.nvim_buf_delete(bufnr, { force = true })
   end