neovim/test/functional/ui/tabline_spec.lua

local helpers = require('test.functional.helpers')(after_each)
local Screen = require('test.functional.ui.screen')
local clear, command, eq = helpers.clear, helpers.command, helpers.eq

describe('ui/tabline', function()
  local screen
  local event_tabs, event_curtab

  before_each(function()
    clear()
    screen = Screen.new(25, 5)
    screen:attach({rgb=true, ext_tabline=true})
    screen:set_on_event_handler(function(name, data)
      if name == "tabline_update" then
        event_curtab, event_tabs = unpack(data)
      end
    end)
  end)

  after_each(function()
    screen:detach()
  end)

  describe('externalized', function()
    it('publishes UI events', function()
      command("tabedit another-tab")

      local expected_tabs = {
        {tab = { id = 1 }, name = '[No Name]'},
        {tab = { id = 2 }, name = 'another-tab'},
      }
      screen:expect([[
        ^                         |
        ~                        |
        ~                        |
        ~                        |
                                 |
      ]], nil, nil, function()
        eq({ id = 2 }, event_curtab)
        eq(expected_tabs, event_tabs)
      end)

      command("tabNext")
      screen:expect([[
        ^                         |
        ~                        |
        ~                        |
        ~                        |
                                 |
      ]], nil, nil, function()
        eq({ id = 1 }, event_curtab)
        eq(expected_tabs, event_tabs)
      end)

    end)
  end)
end)