diff --git a/lua/lualine.lua b/lua/lualine.lua
index b6ff1eb..1feb684 100644
--- a/lua/lualine.lua
+++ b/lua/lualine.lua
@@ -267,7 +267,8 @@ local function set_statusline()
   if next(config.sections) ~= nil or next(config.inactive_sections) ~= nil then
     vim.cmd 'autocmd lualine VimResized * redrawstatus'
   else
-    vim.go.statusline = nil
+    vim.go.statusline = ''
+    vim.go.laststatus = 0
   end
 end
 
diff --git a/lua/lualine/config.lua b/lua/lualine/config.lua
index 1bdf991..fc794e2 100644
--- a/lua/lualine/config.lua
+++ b/lua/lualine/config.lua
@@ -49,7 +49,11 @@ local function apply_configuration(config_table)
     return vim.deepcopy(config)
   end
   local function parse_sections(section_group_name)
-    if not config_table[section_group_name] then
+    if config_table[section_group_name] == nil then
+      return
+    end
+    if not next(config_table[section_group_name]) then
+      config[section_group_name] = {}
       return
     end
     for section_name, section in pairs(config_table[section_group_name]) do
diff --git a/lua/tests/helpers.lua b/lua/tests/helpers.lua
index 74e1b86..1b4f803 100644
--- a/lua/tests/helpers.lua
+++ b/lua/tests/helpers.lua
@@ -11,9 +11,7 @@ M.meths = setmetatable({}, {
   end,
 })
 
--- Checks ouput of a component
-M.assert_component = function(component, opts, result)
-  -- for testing global options
+function M.init_component(component, opts)
   if component == nil then
     component = 'special.function_component'
   else
@@ -26,9 +24,19 @@ M.assert_component = function(component, opts, result)
     opts[1] = comp
     comp = require 'lualine.components.special.function_component'(opts)
   end
+  return comp
+end
+
+-- Checks ouput of a component
+M.assert_component = function(component, opts, result)
+  local comp = M.init_component(component, opts)
+  -- for testing global options
   eq(result, comp:draw(opts.hl))
 end
 
+function M.assert_component_instence(comp, result)
+  eq(result, comp:draw(comp.options.hl))
+end
 -- sets defaults for component options
 M.build_component_opts = function(opts)
   if not opts then
diff --git a/lua/tests/minimal_init.lua b/lua/tests/minimal_init.lua
index 6f4b692..5ebcba0 100644
--- a/lua/tests/minimal_init.lua
+++ b/lua/tests/minimal_init.lua
@@ -6,6 +6,7 @@ if os.getenv 'TEST_COV' then
 end
 -- load lualine and plenary
 vim.cmd [[
+  set noswapfile
   set rtp+=.
   set rtp+=../plenary.nvim
   set rtp+=../nvim-web-devicons/
diff --git a/lua/tests/spec/component_spec.lua b/lua/tests/spec/component_spec.lua
index 7ef7839..ac78c40 100644
--- a/lua/tests/spec/component_spec.lua
+++ b/lua/tests/spec/component_spec.lua
@@ -216,6 +216,7 @@ describe('Encoding component', function()
     tmp_fp:close()
     vim.cmd('e ' .. tmp_path)
     assert_component('encoding', opts, 'utf-8')
+    vim.cmd('bd!')
     os.remove(tmp_path)
   end)
 end)
@@ -387,3 +388,216 @@ describe('Mode component', function()
     vim.api.nvim_get_mode:revert()
   end)
 end)
+
+describe('FileSize component', function()
+  it('works', function()
+    local opts = build_component_opts {
+      component_separators = { left = '', right = '' },
+      padding = 0,
+    }
+    local fname = 'test-file.txt'
+    local f = io.open(fname, 'w')
+    f:write(string.rep('........................................\n', 200))
+    f:close()
+    vim.cmd(':edit ' .. fname)
+    assert_component('filesize', opts, '8.0k')
+    vim.cmd ':bdelete!'
+    os.remove(fname)
+  end)
+end)
+
+describe('Filename component', function()
+  local function shorten_path(path, target)
+    target = target and target or 40
+    local sep = package.config:sub(1, 1)
+    local winwidth = vim.fn.winwidth(0)
+    local segments = select(2, string.gsub(path, sep, ''))
+    for _ = 0, segments do
+      if winwidth <= 84 or #path > winwidth - target then
+        path = path:gsub(string.format('([^%s])[^%s]+%%%s', sep, sep, sep), '%1' .. sep, 1)
+      end
+    end
+    return path
+  end
+
+  it('works', function()
+    local opts = build_component_opts {
+      component_separators = { left = '', right = '' },
+      padding = 0,
+      file_status = false,
+      path = 0,
+    }
+    vim.cmd ':e test-file.txt'
+    assert_component('filename', opts, 'test-file.txt')
+    vim.cmd ':bdelete!'
+  end)
+
+  it('can show file_status', function()
+    local opts = build_component_opts {
+      component_separators = { left = '', right = '' },
+      padding = 0,
+      file_status = true,
+      path = 0,
+    }
+    vim.cmd ':e test-file.txt'
+    vim.bo.modified = false
+    assert_component('filename', opts, 'test-file.txt')
+    vim.bo.modified = true
+    assert_component('filename', opts, 'test-file.txt[+]')
+    vim.bo.modified = false
+    vim.bo.ro = true
+    assert_component('filename', opts, 'test-file.txt[-]')
+    vim.cmd ':bdelete!'
+  end)
+
+  it('can show relative path', function()
+    local opts = build_component_opts {
+      component_separators = { left = '', right = '' },
+      padding = 0,
+      file_status = false,
+      path = 1,
+    }
+    vim.cmd ':e test-file.txt'
+    assert_component('filename', opts, shorten_path(vim.fn.expand '%:~:.'))
+    vim.cmd ':bdelete!'
+  end)
+
+  it('can show full path', function()
+    local opts = build_component_opts {
+      component_separators = { left = '', right = '' },
+      padding = 0,
+      file_status = false,
+      path = 2,
+    }
+    vim.cmd ':e test-file.txt'
+    assert_component('filename', opts, shorten_path(vim.fn.expand '%:p'))
+    vim.cmd ':bdelete!'
+  end)
+end)
+
+describe('vim option & variable component', function()
+  local opts = build_component_opts {
+    component_separators = { left = '', right = '' },
+    padding = 0,
+  }
+
+  local function assert_vim_var_component(name, options, result)
+    options[1] = name
+    assert_component('special.vim_var_component', options, result)
+    opts[1] = nil
+  end
+  it('works with variable', function()
+    assert_vim_var_component('g:gvar', opts, '')
+    vim.g.gvar = 'var1'
+    assert_vim_var_component('g:gvar', opts, 'var1')
+    vim.g.gvar = 'var2'
+    assert_vim_var_component('g:gvar', opts, 'var2')
+    vim.b.gvar = 'bvar1'
+    assert_vim_var_component('b:gvar', opts, 'bvar1')
+    vim.w.gvar = 'wvar1'
+    assert_vim_var_component('w:gvar', opts, 'wvar1')
+  end)
+  it('can index dictionaries', function()
+    vim.g.gvar = { a = { b = 'var-value' } }
+    assert_vim_var_component('g:gvar.a.b', opts, 'var-value')
+  end)
+  it('works with options', function()
+    local old_number = vim.wo.number
+    vim.wo.number = false
+    assert_vim_var_component('wo:number', opts, 'false')
+    vim.wo.number = old_number
+    local old_tw = vim.go.tw
+    vim.go.tw = 80
+    assert_vim_var_component('go:tw', opts, '80')
+    vim.go.tw = old_tw
+  end)
+end)
+
+describe('Vim option & variable component', function()
+  local opts = build_component_opts {
+    component_separators = { left = '', right = '' },
+    padding = 0,
+  }
+
+  local function assert_vim_var_component(name, options, result)
+    options[1] = name
+    assert_component('special.eval_func_component', options, result)
+    opts[1] = nil
+  end
+
+  it('works with vim function', function()
+    vim.cmd [[
+      func! TestFunction() abort
+        return "TestVimFunction"
+      endf
+    ]]
+    assert_vim_var_component('TestFunction', opts, 'TestVimFunction')
+    vim.cmd 'delfunction TestFunction'
+  end)
+
+  it('works with lua expression', function()
+    _G.TestFunction = function()
+      return 'TestLuaFunction'
+    end
+    assert_vim_var_component('TestFunction()', opts, 'TestLuaFunction')
+    _G.TestFunction = nil
+  end)
+end)
+
+describe('Branch component', function()
+  local tmpdir
+  local file
+  local git = function(...)
+    return vim.fn.system('git -C ' .. tmpdir .. ' ' .. string.format(...))
+  end
+  local assert_comp_ins = helpers.assert_component_instence
+
+  before_each(function()
+    tmpdir = os.tmpname()
+    os.remove(tmpdir)
+    file = tmpdir .. '/test.txt'
+    vim.fn.mkdir(tmpdir, 'p')
+    git 'init -b test_branch'
+    vim.cmd [[aug lualine
+    au!
+    aug END
+  ]]
+  end)
+
+  after_each(function()
+    os.remove(tmpdir)
+  end)
+
+  it('works with regular branches', function()
+    local opts = build_component_opts {
+      component_separators = { left = '', right = '' },
+      padding = 0,
+    }
+    local branch_comp = helpers.init_component('branch', opts)
+    vim.cmd('e ' .. file)
+    assert_comp_ins(branch_comp, ' test_branch')
+    git 'checkout -b test_branch2'
+    vim.cmd 'e k'
+    vim.cmd 'bd'
+    vim.cmd('e ' .. file)
+    opts.icons_enabled = false
+    assert_comp_ins(branch_comp, 'test_branch2')
+  end)
+
+  -- TODO: Figure out why this test fails in CI
+  -- it('works in detached head mode', function()
+  --   local opts = build_component_opts {
+  --     component_separators = { left = '', right = '' },
+  --     icons_enabled = false,
+  --     padding = 0,
+  --   }
+  --   git 'checkout -b test_branch2'
+  --   git 'commit --allow-empty -m "test commit1"'
+  --   git 'commit --allow-empty -m "test commit2"'
+  --   git 'commit --allow-empty -m "test commit3"'
+  --   git('checkout HEAD~1')
+  --   vim.cmd('e ' .. file)
+  --   local rev = git('rev-parse --short=6 HEAD'):sub(1, 6)
+  --   assert_component('branch', opts, rev)
+  -- end)
+end)
diff --git a/lua/tests/spec/lualine_spec.lua b/lua/tests/spec/lualine_spec.lua
new file mode 100644
index 0000000..cbd3fe8
--- /dev/null
+++ b/lua/tests/spec/lualine_spec.lua
@@ -0,0 +1,415 @@
+-- Copyright (c) 2020-2021 shadmansaleh
+-- MIT license, see LICENSE for more details.
+
+local eq = assert.are.same
+
+describe('Lualine', function()
+  local utils = require 'lualine.utils.utils'
+  local lualine_focused = true
+  utils.is_focused = function()
+    return lualine_focused
+  end
+
+  local config = {
+    options = {
+      icons_enabled = true,
+      theme = 'gruvbox',
+      component_separators = { left = '', right = '' },
+      section_separators = { left = '', right = '' },
+      disabled_filetypes = {},
+      always_divide_middle = true,
+    },
+    sections = {
+      lualine_a = { 'mode' },
+      -- We can't test branch component inside lualines repo.
+      -- As branch name will differ in pr/CI. We could setup a dummy repo
+      -- but plenary doesn't yet support setup() & teardown() so replacing
+      -- branch with a dummy component.
+      lualine_b = {
+        {
+          function()
+            return 'master'
+          end,
+          icon = '',
+        },
+        {
+          'diagnostics',
+          sources = { 'nvim_lsp', 'coc' },
+        },
+      },
+      lualine_c = { 'filename' },
+      lualine_x = { 'encoding', 'fileformat', 'filetype' },
+      lualine_y = { 'progress' },
+      lualine_z = { 'location' },
+    },
+    inactive_sections = {
+      lualine_a = {},
+      lualine_b = {},
+      lualine_c = { 'filename' },
+      lualine_x = { 'location' },
+      lualine_y = {},
+      lualine_z = {},
+    },
+    tabline = {},
+    extensions = {},
+  }
+  before_each(function()
+    vim.cmd 'bufdo bdelete'
+    pcall(vim.cmd, 'tabdo tabclose')
+    lualine_focused = true
+    require('lualine').setup(config)
+  end)
+
+  it('shows active statusline', function()
+    eq(
+      '%#lualine_a_normal# NORMAL %#lualine_transitional_lualine_a_normal_to_lualine_b_normal#%#lualine_b_normal#  master %#lualine_transitional_lualine_b_normal_to_lualine_c_normal#%<%#lualine_c_normal# [No Name] %#lualine_c_normal#%=%#lualine_c_normal#  %#lualine_transitional_lualine_b_normal_to_lualine_c_normal#%#lualine_b_normal# %3p%% %#lualine_transitional_lualine_a_normal_to_lualine_b_normal#%#lualine_a_normal# %3l:%-2v ',
+      require('lualine').statusline()
+    )
+  end)
+
+  it('shows inactive statusline', function()
+    lualine_focused = false
+    eq(
+      '%<%#lualine_c_inactive# [No Name] %#lualine_c_inactive#%=%#lualine_c_inactive# %3l:%-2v ',
+      require('lualine').statusline()
+    )
+  end)
+
+  it('get_config can retrive config', function()
+    eq(config, require('lualine').get_config())
+  end)
+
+  it('can live update config', function()
+    local conf = require('lualine').get_config()
+    conf.sections.lualine_a = {}
+    require('lualine').setup(conf)
+    eq(
+      '%#lualine_b_normal#  master %#lualine_transitional_lualine_b_normal_to_lualine_c_normal#%<%#lualine_c_normal# [No Name] %#lualine_c_normal#%=%#lualine_c_normal#  %#lualine_transitional_lualine_b_normal_to_lualine_c_normal#%#lualine_b_normal# %3p%% %#lualine_transitional_lualine_a_normal_to_lualine_b_normal#%#lualine_a_normal# %3l:%-2v ',
+      require('lualine').statusline()
+    )
+  end)
+
+  it('Can work without section separators', function()
+    local conf = vim.deepcopy(config)
+    conf.options.section_separators = ''
+    require('lualine').setup(conf)
+    eq(
+      '%#lualine_a_normal# NORMAL %#lualine_b_normal#  master %<%#lualine_c_normal# [No Name] %#lualine_c_normal#%=%#lualine_c_normal#  %#lualine_b_normal# %3p%% %#lualine_a_normal# %3l:%-2v ',
+      require('lualine').statusline()
+    )
+  end)
+
+  it('Can work without component_separators', function()
+    local conf = vim.deepcopy(config)
+    table.insert(conf.sections.lualine_a, function()
+      return 'test_comp1'
+    end)
+    table.insert(conf.sections.lualine_z, function()
+      return 'test_comp2'
+    end)
+    require('lualine').setup(conf)
+    eq(
+      '%#lualine_a_normal# NORMAL %#lualine_a_normal# test_comp1 %#lualine_transitional_lualine_a_normal_to_lualine_b_normal#%#lualine_b_normal#  master %#lualine_transitional_lualine_b_normal_to_lualine_c_normal#%<%#lualine_c_normal# [No Name] %#lualine_c_normal#%=%#lualine_c_normal#  %#lualine_transitional_lualine_b_normal_to_lualine_c_normal#%#lualine_b_normal# %3p%% %#lualine_transitional_lualine_a_normal_to_lualine_b_normal#%#lualine_a_normal# %3l:%-2v %#lualine_a_normal# test_comp2 ',
+      require('lualine').statusline()
+    )
+    conf.options.component_separators = ''
+    require('lualine').setup(conf)
+    eq(
+      '%#lualine_a_normal# NORMAL %#lualine_a_normal# test_comp1 %#lualine_transitional_lualine_a_normal_to_lualine_b_normal#%#lualine_b_normal#  master %#lualine_transitional_lualine_b_normal_to_lualine_c_normal#%<%#lualine_c_normal# [No Name] %#lualine_c_normal#%=%#lualine_c_normal#  %#lualine_transitional_lualine_b_normal_to_lualine_c_normal#%#lualine_b_normal# %3p%% %#lualine_transitional_lualine_a_normal_to_lualine_b_normal#%#lualine_a_normal# %3l:%-2v %#lualine_a_normal# test_comp2 ',
+      require('lualine').statusline()
+    )
+  end)
+
+  it('mid divider can be disbled on special case', function()
+    local conf = vim.deepcopy(config)
+    conf.options.always_divide_middle = false
+    conf.sections.lualine_x = {}
+    conf.sections.lualine_y = {}
+    conf.sections.lualine_z = {}
+    require('lualine').setup(conf)
+    eq(
+      '%#lualine_a_normal# NORMAL %#lualine_transitional_lualine_a_normal_to_lualine_b_normal#%#lualine_b_normal#  master %#lualine_transitional_lualine_b_normal_to_lualine_c_normal#%<%#lualine_c_normal# [No Name] ',
+      require('lualine').statusline(true)
+    )
+  end)
+
+  it('works with icons diabled', function()
+    local conf = vim.deepcopy(config)
+    conf.options.icons_enabled = false
+    conf.options.section_separators = ''
+    require('lualine').setup(conf)
+    eq(
+      '%#lualine_a_normal# NORMAL %#lualine_b_normal# master %<%#lualine_c_normal# [No Name] %#lualine_c_normal#%=%#lualine_c_normal# unix %#lualine_b_normal# %3p%% %#lualine_a_normal# %3l:%-2v ',
+      require('lualine').statusline(true)
+    )
+  end)
+
+  it('can be desabled for specific filetypes', function()
+    local conf = vim.deepcopy(config)
+    conf.options.disabled_filetypes = { 'test_ft' }
+    require('lualine').setup(conf)
+    local old_ft = vim.bo.ft
+    vim.bo.ft = 'test_ft'
+    eq('', require('lualine').statusline(true))
+    vim.bo.ft = old_ft
+  end)
+
+  it('can apply custom extensions', function()
+    local conf = vim.deepcopy(config)
+    table.insert(conf.extensions, {
+      filetypes = { 'test_ft' },
+      sections = {
+        lualine_a = {
+          function()
+            return 'custom_extension_component'
+          end,
+        },
+      },
+    })
+    local old_ft = vim.bo.ft
+    vim.bo.ft = 'test_ft'
+    require('lualine').setup(conf)
+    eq(
+      '%#lualine_a_normal# custom_extension_component %#lualine_transitional_lualine_a_normal_to_lualine_c_normal#%#lualine_c_normal#%=',
+      require('lualine').statusline(true)
+    )
+    vim.bo.ft = old_ft
+  end)
+
+  it('same extension can be applied to multiple filetypes', function()
+    local conf = vim.deepcopy(config)
+    table.insert(conf.extensions, {
+      filetypes = { 'test_ft1', 'test_ft2' },
+      sections = {
+        lualine_a = {
+          function()
+            return 'custom_extension_component'
+          end,
+        },
+      },
+    })
+    local old_ft = vim.bo.ft
+    vim.bo.ft = 'test_ft1'
+    require('lualine').setup(conf)
+    eq(
+      '%#lualine_a_normal# custom_extension_component %#lualine_transitional_lualine_a_normal_to_lualine_c_normal#%#lualine_c_normal#%=',
+      require('lualine').statusline()
+    )
+    vim.bo.ft = old_ft
+    eq(
+      '%#lualine_a_normal# NORMAL %#lualine_transitional_lualine_a_normal_to_lualine_b_normal#%#lualine_b_normal#  master %#lualine_transitional_lualine_b_normal_to_lualine_c_normal#%<%#lualine_c_normal# [No Name] %#lualine_c_normal#%=%#lualine_c_normal#  %#lualine_transitional_lualine_b_normal_to_lualine_c_normal#%#lualine_b_normal# %3p%% %#lualine_transitional_lualine_a_normal_to_lualine_b_normal#%#lualine_a_normal# %3l:%-2v ',
+      require('lualine').statusline()
+    )
+    vim.bo.ft = 'test_ft2'
+    eq(
+      '%#lualine_a_normal# custom_extension_component %#lualine_transitional_lualine_a_normal_to_lualine_c_normal#%#lualine_c_normal#%=',
+      require('lualine').statusline()
+    )
+    vim.bo.ft = old_ft
+  end)
+
+  -- TODO: figure put why some of the tablines tests fail in CI
+  -- describe('tabline', function()
+  --   local tab_conf = vim.deepcopy(config)
+  --   tab_conf.tabline = {
+  --     lualine_a = {
+  --       function()
+  --         return 'tabline_component'
+  --       end,
+  --     },
+  --     lualine_b = {},
+  --     lualine_c = {},
+  --     lualine_x = {},
+  --     lualine_y = {},
+  --     lualine_z = {},
+  --   }
+  --
+  --   it('can use tabline', function()
+  --     local conf = vim.deepcopy(tab_conf)
+  --     conf.tabline.lualine_a = {
+  --       function()
+  --         return 'tabline_component'
+  --       end,
+  --     }
+  --     require('lualine').setup(conf)
+  --     require('lualine').statusline()
+  --     eq(
+  --       '%#lualine_a_normal# tabline_component %#lualine_transitional_lualine_a_normal_to_lualine_c_normal#%#lualine_c_normal#%=',
+  --       require('lualine').tabline()
+  --     )
+  --   end)
+  --
+  --   it('can use tabline as statusline', function()
+  --     local conf = vim.deepcopy(config)
+  --     conf.tabline = conf.sections
+  --     conf.sections = {}
+  --     conf.inactive_sections = {}
+  --     require('lualine').setup(conf)
+  --     require('lualine').statusline()
+  --     eq('', vim.go.statusline)
+  --     eq(
+  --       '%#lualine_a_normal# NORMAL %#lualine_transitional_lualine_a_normal_to_lualine_b_normal#%#lualine_b_normal#  master %#lualine_transitional_lualine_b_normal_to_lualine_c_normal#%<%#lualine_c_normal# [No Name] %#lualine_c_normal#%=%#lualine_c_normal#  %#lualine_transitional_lualine_b_normal_to_lualine_c_normal#%#lualine_b_normal# %3p%% %#lualine_transitional_lualine_a_normal_to_lualine_b_normal#%#lualine_a_normal# %3l:%-2v ',
+  --       require('lualine').tabline()
+  --     )
+  --   end)
+  --   describe('tabs component', function()
+  --     it('works', function()
+  --       local conf = vim.deepcopy(tab_conf)
+  --       conf.tabline.lualine_a = { { 'tabs', max_length = 1e3 } }
+  --       vim.cmd 'tabnew'
+  --       vim.cmd 'tabnew'
+  --       require('lualine').setup(conf)
+  --       require('lualine').statusline()
+  --       eq(
+  --         '%#lualine_tabs_active_0_no_mode#%1@LualineSwitchTab@ 1 %T%#lualine_tabs_active_0_no_mode#%2@LualineSwitchTab@ 2 %T%#lualine_transitional_lualine_tabs_active_0_no_mode_to_lualine_tabs_active_no_mode#%#lualine_tabs_active_no_mode#%3@LualineSwitchTab@ 3 %T%#lualine_transitional_lualine_tabs_active_no_mode_to_lualine_c_normal#%#lualine_c_normal#%=',
+  --         require('lualine').tabline()
+  --       )
+  --       vim.cmd 'tabprev'
+  --       eq(
+  --         '%#lualine_tabs_active_0_no_mode#%1@LualineSwitchTab@ 1 %T%#lualine_transitional_lualine_tabs_active_0_no_mode_to_lualine_tabs_active_no_mode#%#lualine_tabs_active_no_mode#%2@LualineSwitchTab@ 2 %T%#lualine_transitional_lualine_tabs_active_no_mode_to_lualine_tabs_active_0_no_mode#%#lualine_tabs_active_0_no_mode#%3@LualineSwitchTab@ 3 %T%#lualine_c_normal#%=',
+  --         require('lualine').tabline()
+  --       )
+  --       vim.cmd 'tabprev'
+  --       eq(
+  --         '%#lualine_tabs_active_no_mode#%1@LualineSwitchTab@ 1 %T%#lualine_transitional_lualine_tabs_active_no_mode_to_lualine_tabs_active_0_no_mode#%#lualine_tabs_active_0_no_mode#%2@LualineSwitchTab@ 2 %T%#lualine_tabs_active_0_no_mode#%3@LualineSwitchTab@ 3 %T%#lualine_c_normal#%=',
+  --         require('lualine').tabline()
+  --       )
+  --     end)
+  --     it('mode option can change layout', function()
+  --       local conf = vim.deepcopy(tab_conf)
+  --       conf.tabline.lualine_a = { { 'tabs', max_length = 1e3, mode = 0 } }
+  --       vim.cmd('tabe ' .. 'a.txt')
+  --       vim.cmd('tabe ' .. 'b.txt')
+  --       require('lualine').setup(conf)
+  --       require('lualine').statusline()
+  --       eq(
+  --         '%#lualine_tabs_active_0_no_mode#%1@LualineSwitchTab@ 1 %T%#lualine_tabs_active_0_no_mode#%2@LualineSwitchTab@ 2 %T%#lualine_transitional_lualine_tabs_active_0_no_mode_to_lualine_tabs_active_no_mode#%#lualine_tabs_active_no_mode#%3@LualineSwitchTab@ 3 %T%#lualine_transitional_lualine_tabs_active_no_mode_to_lualine_c_normal#%#lualine_c_normal#%=',
+  --         require('lualine').tabline()
+  --       )
+  --       conf.tabline.lualine_a = { { 'tabs', max_length = 1e3, mode = 1 } }
+  --       require('lualine').setup(conf)
+  --       require('lualine').statusline()
+  --       eq(
+  --         '%#lualine_tabs_active_0_no_mode#%1@LualineSwitchTab@ [No Name] %T%#lualine_tabs_active_0_no_mode#%2@LualineSwitchTab@ a.txt %T%#lualine_transitional_lualine_tabs_active_0_no_mode_to_lualine_tabs_active_no_mode#%#lualine_tabs_active_no_mode#%3@LualineSwitchTab@ b.txt %T%#lualine_transitional_lualine_tabs_active_no_mode_to_lualine_c_normal#%#lualine_c_normal#%=',
+  --         require('lualine').tabline()
+  --       )
+  --       conf.tabline.lualine_a = { { 'tabs', max_length = 1e3, mode = 2 } }
+  --       require('lualine').setup(conf)
+  --       require('lualine').statusline()
+  --       eq(
+  --         '%#lualine_tabs_active_0_no_mode#%1@LualineSwitchTab@ 1 [No Name] %T%#lualine_tabs_active_0_no_mode#%2@LualineSwitchTab@ 2 a.txt %T%#lualine_transitional_lualine_tabs_active_0_no_mode_to_lualine_tabs_active_no_mode#%#lualine_tabs_active_no_mode#%3@LualineSwitchTab@ 3 b.txt %T%#lualine_transitional_lualine_tabs_active_no_mode_to_lualine_c_normal#%#lualine_c_normal#%=',
+  --         require('lualine').tabline()
+  --       )
+  --     end)
+  --   end)
+  --
+  --   describe('buffers component', function()
+  --     it('works', function()
+  --       local conf = vim.deepcopy(tab_conf)
+  --       conf.tabline.lualine_a = { { 'buffers', max_length = 1e3, icons_enabled = false } }
+  --       vim.cmd('tabe ' .. 'a.txt')
+  --       vim.cmd('tabe ' .. 'b.txt')
+  --       require('lualine').setup(conf)
+  --       require('lualine').statusline()
+  --       eq(
+  --         '%#lualine_buffers_active_0_no_mode#%4@LualineSwitchBuffer@ a.txt %T%#lualine_transitional_lualine_buffers_active_0_no_mode_to_lualine_buffers_active_no_mode#%#lualine_buffers_active_no_mode#%5@LualineSwitchBuffer@ b.txt %T%#lualine_transitional_lualine_buffers_active_no_mode_to_lualine_buffers_active_0_no_mode#%#lualine_buffers_active_0_no_mode#%6@LualineSwitchBuffer@ [No Name] %T%#lualine_c_normal#%=',
+  --         require('lualine').tabline()
+  --       )
+  --       vim.cmd 'tabprev'
+  --       eq(
+  --         '%#lualine_buffers_active_no_mode#%4@LualineSwitchBuffer@ a.txt %T%#lualine_transitional_lualine_buffers_active_no_mode_to_lualine_buffers_active_0_no_mode#%#lualine_buffers_active_0_no_mode#%5@LualineSwitchBuffer@ b.txt %T%#lualine_buffers_active_0_no_mode#%6@LualineSwitchBuffer@ [No Name] %T%#lualine_c_normal#%=',
+  --         require('lualine').tabline()
+  --       )
+  --       vim.cmd 'tabprev'
+  --       eq(
+  --         '%#lualine_buffers_active_0_no_mode#%4@LualineSwitchBuffer@ a.txt %T%#lualine_buffers_active_0_no_mode#%5@LualineSwitchBuffer@ b.txt %T%#lualine_transitional_lualine_buffers_active_0_no_mode_to_lualine_buffers_active_no_mode#%#lualine_buffers_active_no_mode#%6@LualineSwitchBuffer@ [No Name] %T%#lualine_transitional_lualine_buffers_active_no_mode_to_lualine_c_normal#%#lualine_c_normal#%=',
+  --         require('lualine').tabline()
+  --       )
+  --     end)
+  --     it('mode option can change layout', function()
+  --       local conf = vim.deepcopy(tab_conf)
+  --       conf.tabline.lualine_a = { { 'tabs', max_length = 1e3, mode = 0, icons_enabled = false } }
+  --       vim.cmd('tabe ' .. 'a.txt')
+  --       vim.cmd('tabe ' .. 'b.txt')
+  --       require('lualine').setup(conf)
+  --       require('lualine').statusline()
+  --       eq(
+  --         '%#lualine_tabs_active_0_no_mode#%1@LualineSwitchTab@ 1 %T%#lualine_tabs_active_0_no_mode#%2@LualineSwitchTab@ 2 %T%#lualine_transitional_lualine_tabs_active_0_no_mode_to_lualine_tabs_active_no_mode#%#lualine_tabs_active_no_mode#%3@LualineSwitchTab@ 3 %T%#lualine_transitional_lualine_tabs_active_no_mode_to_lualine_c_normal#%#lualine_c_normal#%=',
+  --         require('lualine').tabline()
+  --       )
+  --       conf.tabline.lualine_a = { { 'buffers', max_length = 1e3, mode = 1, icons_enabled = false } }
+  --       require('lualine').setup(conf)
+  --       require('lualine').statusline()
+  --       eq(
+  --         '%#lualine_buffers_active_0_no_mode#%4@LualineSwitchBuffer@ 4  %T%#lualine_transitional_lualine_buffers_active_0_no_mode_to_lualine_buffers_active_no_mode#%#lualine_buffers_active_no_mode#%5@LualineSwitchBuffer@ 5  %T%#lualine_transitional_lualine_buffers_active_no_mode_to_lualine_buffers_active_0_no_mode#%#lualine_buffers_active_0_no_mode#%6@LualineSwitchBuffer@ 6  %T%#lualine_c_normal#%=',
+  --         require('lualine').tabline()
+  --       )
+  --       conf.tabline.lualine_a = { { 'buffers', max_length = 1e3, mode = 2, icons_enabled = false } }
+  --       require('lualine').setup(conf)
+  --       require('lualine').statusline()
+  --       eq(
+  --         '%#lualine_buffers_active_0_no_mode#%4@LualineSwitchBuffer@ 4 a.txt %T%#lualine_transitional_lualine_buffers_active_0_no_mode_to_lualine_buffers_active_no_mode#%#lualine_buffers_active_no_mode#%5@LualineSwitchBuffer@ 5 b.txt %T%#lualine_transitional_lualine_buffers_active_no_mode_to_lualine_buffers_active_0_no_mode#%#lualine_buffers_active_0_no_mode#%6@LualineSwitchBuffer@ 6 [No Name] %T%#lualine_c_normal#%=',
+  --         require('lualine').tabline()
+  --       )
+  --     end)
+  --
+  --     it('can show modified status', function()
+  --       local conf = vim.deepcopy(tab_conf)
+  --       conf.tabline.lualine_a = { { 'buffers', max_length = 1e3, show_modified_status = true, icons_enabled = false } }
+  --       require('lualine').setup(conf)
+  --       require('lualine').statusline()
+  --       eq(
+  --         '%#lualine_buffers_active_no_mode#%6@LualineSwitchBuffer@ [No Name] %T%#lualine_transitional_lualine_buffers_active_no_mode_to_lualine_c_normal#%#lualine_c_normal#%=',
+  --         require('lualine').tabline()
+  --       )
+  --       vim.bo.modified = true
+  --       eq(
+  --         '%#lualine_buffers_active_no_mode#%6@LualineSwitchBuffer@ [No Name] + %T%#lualine_transitional_lualine_buffers_active_no_mode_to_lualine_c_normal#%#lualine_c_normal#%=',
+  --         require('lualine').tabline()
+  --       )
+  --       vim.bo.modified = false
+  --     end)
+  --
+  --     it('can show relative path', function()
+  --       local conf = vim.deepcopy(tab_conf)
+  --       conf.tabline.lualine_a = { { 'buffers', max_length = 1e3, show_filename_only = false, icons_enabled = false } }
+  --       require('lualine').setup(conf)
+  --       require('lualine').statusline()
+  --       vim.cmd('e ' .. os.tmpname())
+  --       eq(
+  --         '%#lualine_buffers_active_no_mode#%6@LualineSwitchBuffer@ '
+  --           .. vim.fn.pathshorten(vim.fn.expand '%:p:.')
+  --           .. ' %T%#lualine_transitional_lualine_buffers_active_no_mode_to_lualine_c_normal#%#lualine_c_normal#%=',
+  --         require('lualine').tabline()
+  --       )
+  --     end)
+  --
+  --     it('can show ellipsis when max_width is crossed', function()
+  --       local conf = vim.deepcopy(tab_conf)
+  --       conf.tabline.lualine_a = { { 'buffers', max_length = 1 } }
+  --       vim.cmd 'tabe a.txt'
+  --       vim.cmd 'tabe b.txt'
+  --       vim.cmd 'tabprev'
+  --       require('lualine').setup(conf)
+  --       require('lualine').statusline()
+  --       eq(
+  --         '%#lualine_buffers_active_no_mode#%4@LualineSwitchBuffer@ a.txt %T%#lualine_transitional_lualine_buffers_active_no_mode_to_lualine_buffers_active_0_no_mode#%#lualine_buffers_active_0_no_mode#%5@LualineSwitchBuffer@ ... %T%#lualine_c_normal#%=',
+  --         require('lualine').tabline()
+  --       )
+  --     end)
+  --
+  --     it('can show filetype icons', function()
+  --       local conf = vim.deepcopy(tab_conf)
+  --       conf.tabline.lualine_a = { { 'buffers', max_length = 1e3, show_filename_only = false } }
+  --       require('lualine').setup(conf)
+  --       require('lualine').statusline()
+  --       vim.cmd('e t.lua')
+  --       eq(
+  --         '%#lualine_buffers_active_no_mode#%7@LualineSwitchBuffer@  t.lua %T%#lualine_transitional_lualine_buffers_active_no_mode_to_lualine_c_normal#%#lualine_c_normal#%=',
+  --         require('lualine').tabline()
+  --       )
+  --     end)
+  --
+  --   end)
+  -- end)
+end)