Quick and dirty Neovim unit-test runner

unit-test.lua

local M = {
    buf_nr = nil,
    suites = {},
    window_title = "Results: ",
    buffer_namespace = { name = "ResultWindowNS", id = nil },
}

M.clear_internal_buffer = function()
    if M.buf_nr ~= nil and vim.fn.bufexists(M.buf_nr) then
        vim.api.nvim_buf_delete(M.buf_nr, { force = true })
        M.buf_nr = nil
    end
end

M.setup_buffer = function()
    M.clear_internal_buffer()
    M.buf_nr = vim.api.nvim_create_buf(false, true)
    vim.bo[M.buf_nr].bufhidden = "wipe"

    M.buffer_namespace.id = vim.api.nvim_create_namespace(M.buffer_namespace.name) -- Won't be recreated if it already exists
    vim.api.nvim_buf_clear_namespace(M.buf_nr, M.buffer_namespace.id, 0, -1)

    -- Key mappings for closing the window (tied to the scratch buffer only)
    local map_opts = { noremap = true, silent = true }
    vim.api.nvim_buf_set_keymap(M.buf_nr, "n", "q", "<cmd>bd!<CR>", map_opts)
    vim.api.nvim_buf_set_keymap(M.buf_nr, "n", "<Esc>", "<cmd>bd!<CR>", map_opts)

    vim.api.nvim_create_autocmd({ "BufDelete", "BufWipeout" }, {
        group = vim.api.nvim_create_augroup("ResultWindowGroup", { clear = true }),
        callback = function()
            M.buf_nr = nil
        end,
    })
end

M.open_floating_window = function()
    assert(M.buf_nr, "Buffer should have been initialized before opening window")

    -- Define the floating window size and position
    local width = math.floor(vim.api.nvim_get_option("columns") / 2)
    local height = math.floor(vim.api.nvim_get_option("lines") / 2)

    -- Set window options (defined here :h nvim_open_win)
    local opts = {
        relative = "editor",
        width = width,
        height = height,
        col = math.floor(vim.api.nvim_get_option("columns") / 4),
        row = math.floor(vim.api.nvim_get_option("lines") / 4),
        style = "minimal",
        border = "rounded",
        title = " Results ",
        title_pos = "left",
    }

    -- Create the floating window
    local win = vim.api.nvim_open_win(M.buf_nr, true, opts)
    vim.wo[win].wrap = true

    -- Set custom highlight (see :h api-floatwin)
    vim.api.nvim_set_option_value("winhl", "FloatTitle:PmenuSel", { win = win })
end

-- TODO Move to utils
M.error_callback = function(err)
    return err
end

M.test_runner = function(name, func)
    local result, ret = xpcall(func, M.error_callback)

    if result then
        return true, name
    end

    return false, name .. ", reason: " .. ret
end

M.suite_runner = function(func)
    local run_results = {}

    local function it(test_name, test_func)
        local result, msg = M.test_runner(test_name, test_func)
        table.insert(run_results, { status = result, message = msg })
    end
    local result, ret = xpcall(func, M.error_callback, it)
    return result, run_results, ret
end

M.describe = function(suite_name, suite_func)
    M.suites[suite_name] = function()
        return M.suite_runner(suite_func)
    end
end

-- TODO Cleanup this function
M.run = function()
    M.setup_buffer()
    M.open_floating_window()

    local print_index = 0
    for name, runner in pairs(M.suites) do
        local result, run_results, msg = runner()

        if not result then
            local message = "Suite " .. name .. " failed: " .. msg
            vim.api.nvim_buf_set_lines(M.buf_nr, print_index, -1, false, { message, "" })
            print_index = -1
        else
            local passed = vim.tbl_filter(function(r)
                return r.status
            end, run_results)
            local message = "Suite " .. name .. " results"
            vim.api.nvim_buf_set_lines(M.buf_nr, print_index, -1, false, { message })
            local virt_text = {}

            if #passed > 0 then
                table.insert(virt_text, { "Passed: " .. #passed, "DiagnosticSignOk" })
                table.insert(virt_text, { " " })
            end
            if #passed < #run_results then
                table.insert(virt_text, { "Failed: " .. (#run_results - #passed), "DiagnosticSignError" })
            end
            vim.api.nvim_buf_set_extmark(
                M.buf_nr,
                M.buffer_namespace.id,
                vim.api.nvim_buf_line_count(M.buf_nr) - 1,
                0,
                { virt_text = virt_text }
            )
            print_index = -1

            for i, v in ipairs(run_results) do
                vim.api.nvim_buf_set_lines(
                    M.buf_nr,
                    -1,
                    -1,
                    false,
                    { "[" .. i .. "/" .. #run_results .. "] " .. v.message }
                )

                local hl_grp_name = v.status and "DiagnosticSignOk" or "DiagnosticSignError"
                local text = v.status and "Passed" or "Failed"
                vim.api.nvim_buf_set_extmark(
                    M.buf_nr,
                    M.buffer_namespace.id,
                    vim.api.nvim_buf_line_count(M.buf_nr) - 1,
                    0,
                    { virt_text = { { text, hl_grp_name } } }
                )
            end
            vim.api.nvim_buf_set_lines(M.buf_nr, print_index, -1, false, { "" })
        end
    end
end

return M