feat(tests): Add baseline testing using Plenary's Busted hooks

Makefile

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+.PHONY: test
+test:
+	nvim --headless --noplugin -u tests/mininit.lua -c "PlenaryBustedDirectory tests/neo-tree/ { minimal_init = 'tests/mininit.lua' }"
+
+.PHONY: format
+format:
+	stylua ./lua ./tests

tests/helpers/util.lua

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+local utils = {}
+
+local Path = require("plenary.path")
+local testdir = Path:new(vim.env.TMPDIR or "/tmp", "neo-tree-testing"):absolute()
+
+local function rm_test_dir()
+  if vim.fn.isdirectory(testdir) == 1 then
+    vim.fn.delete(testdir, "rf")
+  end
+end
+
+utils.setup_test_fs = function()
+  rm_test_dir()
+
+  -- Need a list-style map here to ensure that things happen in the correct order.
+  --
+  -- When/if editing this, be cautious as (for now) other tests might be accessing
+  -- files from within this array by index
+  local fs = {
+    basedir = testdir,
+    content = {
+      {
+        name = "foo",
+        type = "dir",
+        content = {
+          { name = "foofile1.txt", type = "file" },
+          { name = "foofile2.txt", type = "file" },
+        },
+      },
+      { name = "bar", type = "dir" },
+      { name = "topfile1.txt", type = "file" },
+    },
+  }
+  local function makefs(content, basedir)
+    for _, info in ipairs(content) do
+      if info.type == "dir" then
+        info.abspath = Path:new(basedir, info.name):absolute()
+        vim.fn.mkdir(info.abspath, "p")
+        if info.content then
+          makefs(info.content, info.abspath)
+        end
+      elseif info.type == "file" then
+        info.abspath = Path:new(basedir, info.name):absolute()
+        vim.fn.writefile({}, info.abspath)
+      end
+    end
+  end
+  makefs(fs.content, testdir)
+  vim.cmd("tcd " .. testdir)
+  return fs
+end
+
+utils.teardown_test_fs = function()
+  rm_test_dir()
+end
+
+utils.clear_test_state = function()
+  -- TODO: Clear internal state?
+  vim.cmd("top new | wincmd o")
+  local keepbufnr = vim.api.nvim_get_current_buf()
+  for _, bufnr in ipairs(vim.api.nvim_list_bufs()) do
+    if bufnr ~= keepbufnr then
+      vim.api.nvim_buf_delete(bufnr, { force = true })
+    end
+  end
+  assert(#vim.api.nvim_tabpage_list_wins(0) == 1, "Failed to properly clear tab")
+  assert(#vim.api.nvim_list_bufs() == 1, "Failed to properly clear buffers")
+end
+
+utils.editfile = function(testfile)
+  vim.cmd("e " .. testfile)
+  assert.are.same(vim.fn.fnamemodify(vim.api.nvim_buf_get_name(0), ":p"), vim.fn.fnamemodify(testfile, ":p"))
+end
+
+return utils

tests/helpers/verify.lua

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+local verify = {}
+
+verify.eventually = function(timeout, assertfunc, failmsg, ...)
+  local success, args = false, { ... }
+  vim.wait(timeout or 1000, function()
+    success = assertfunc(unpack(args))
+    return success
+  end)
+  assert(success, failmsg)
+end
+
+verify.after = function(timeout, assertfunc, failmsg)
+  vim.wait(timeout, function()
+    return false
+  end)
+  assert(assertfunc(), failmsg)
+end
+
+verify.bufnr_is_not = function(start_bufnr, timeout)
+  verify.eventually(timeout or 500, function()
+    return start_bufnr ~= vim.api.nvim_get_current_buf()
+  end, string.format("Current buffer is '%s' when expected to not be", start_bufnr))
+end
+
+verify.tree_focused = function(timeout)
+  verify.eventually(timeout or 1000, function()
+    return vim.api.nvim_buf_get_option(0, "filetype") == "neo-tree"
+  end, "Current buffer is not a 'neo-tree' filetype")
+end
+
+verify.tree_node_is = function(expected_node_id, timeout)
+  verify.eventually(timeout or 500, function()
+    local state = require("neo-tree.sources.manager").get_state("filesystem")
+    local node = state.tree:get_node()
+    if not node then
+      return false
+    end
+    local node_id = node:get_id()
+    if node_id ~= expected_node_id then
+      return false
+    end
+    if state.position.node_id ~= expected_node_id then
+      return false
+    end
+    return true
+  end, string.format("Tree node '%s' not focused", expected_node_id))
+end
+
+return verify

tests/mininit.lua

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+-- Need the absolute path as when doing the testing we will issue things like `tcd` to change directory
+-- to where our temporary filesystem lives
+vim.opt.rtp = {
+  vim.fn.fnamemodify(vim.trim(vim.fn.system("git rev-parse --show-toplevel")), ":p"),
+  vim.env.VIMRUNTIME,
+}
+
+vim.cmd([[
+  packadd plenary.nvim
+  packadd nui.nvim
+]])
+
+require("neo-tree").setup()
+
+vim.opt.swapfile = false
+
+vim.cmd([[
+  runtime plugin/neo-tree.vim
+]])
+
+-- For debugging
+P = function(...)
+  print(unpack(vim.tbl_map(vim.inspect, { ... })))
+end