feat(test): testing infrastructure

spec/helpers.lua

@@ -0,0 +1,23 @@
+vim.cmd([[set runtimepath=$VIMRUNTIME]])
+vim.opt.runtimepath:append(vim.fn.getcwd())
+vim.opt.packpath = {}
+
+local M = {}
+
+function M.create_buffer(lines)
+  local bufnr = vim.api.nvim_create_buf(false, true)
+  vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, lines or {})
+  return bufnr
+end
+
+function M.delete_buffer(bufnr)
+  if bufnr and vim.api.nvim_buf_is_valid(bufnr) then
+    vim.api.nvim_buf_delete(bufnr, { force = true })
+  end
+end
+
+function M.get_extmarks(bufnr, ns)
+  return vim.api.nvim_buf_get_extmarks(bufnr, ns, 0, -1, { details = true })
+end
+
+return M