functests: Replace execute with either command or feed_command

Hope this will make people using feed_command less likely: this hides bugs.
Already found at least two:

1. msgpackparse() will show internal error: hash_add() in case of duplicate
   keys, though it will still work correctly. Currently silenced.
2. ttimeoutlen was spelled incorrectly, resulting in option not being set when
   expected. Test was still functioning somehow though. Currently fixed.

11 files changed, 272 insertions, 266 deletions

diff --git a/test/functional/ui/bufhl_spec.lua b/test/functional/ui/bufhl_spec.lua
index 53fe303762..b0be91c4e9 100644
--- a/test/functional/ui/bufhl_spec.lua
+++ b/test/functional/ui/bufhl_spec.lua
@@ -1,7 +1,7 @@
 local helpers = require('test.functional.helpers')(after_each)
 local Screen = require('test.functional.ui.screen')
 local clear, feed, insert = helpers.clear, helpers.feed, helpers.insert
-local execute, request, neq = helpers.execute, helpers.request, helpers.neq
+local command, request, neq = helpers.command, helpers.request, helpers.neq
 
 if helpers.pending_win32(pending) then return end
 
@@ -11,7 +11,7 @@ describe('Buffer highlighting', function()
 
   before_each(function()
     clear()
-    execute("syntax on")
+    command("syntax on")
     screen = Screen.new(40, 8)
     screen:attach()
     screen:set_default_attr_ids({
@@ -106,7 +106,7 @@ describe('Buffer highlighting', function()
         combining highlights
         from different sources]])
 
-      execute("hi ImportantWord gui=bold cterm=bold")
+      command("hi ImportantWord gui=bold cterm=bold")
       id1 = add_hl(0, "ImportantWord", 0, 2, 8)
       add_hl(id1, "ImportantWord", 1, 12, -1)
       add_hl(id1, "ImportantWord", 2, 0, 9)
@@ -192,7 +192,7 @@ describe('Buffer highlighting', function()
                                                 |
       ]])
 
-      execute(':3move 4')
+      command(':3move 4')
       screen:expect([[
         a {5:longer} example                        |
                                                 |
diff --git a/test/functional/ui/highlight_spec.lua b/test/functional/ui/highlight_spec.lua
index 05cf3231ea..5f8fafef07 100644
--- a/test/functional/ui/highlight_spec.lua
+++ b/test/functional/ui/highlight_spec.lua
@@ -2,7 +2,7 @@ local helpers = require('test.functional.helpers')(after_each)
 local Screen = require('test.functional.ui.screen')
 local os = require('os')
 local clear, feed, insert = helpers.clear, helpers.feed, helpers.insert
-local execute, request, eq = helpers.execute, helpers.request, helpers.eq
+local feed_command, request, eq = helpers.feed_command, helpers.request, helpers.eq
 
 if helpers.pending_win32(pending) then return end
 
@@ -41,18 +41,18 @@ describe('manual syntax highlight', function()
   end)
 
   it("works with buffer switch and 'hidden'", function()
-    execute('e tmp1.vim')
-    execute('e Xtest-functional-ui-highlight.tmp.vim')
-    execute('filetype on')
-    execute('syntax manual')
-    execute('set ft=vim')
-    execute('set syntax=ON')
+    feed_command('e tmp1.vim')
+    feed_command('e Xtest-functional-ui-highlight.tmp.vim')
+    feed_command('filetype on')
+    feed_command('syntax manual')
+    feed_command('set ft=vim')
+    feed_command('set syntax=ON')
     feed('iecho 1<esc>0')
 
-    execute('set hidden')
-    execute('w')
-    execute('bn')
-    execute('bp')
+    feed_command('set hidden')
+    feed_command('w')
+    feed_command('bn')
+    feed_command('bp')
     screen:expect([[
       {1:^echo} 1              |
       {0:~                   }|
@@ -63,18 +63,18 @@ describe('manual syntax highlight', function()
   end)
 
   it("works with buffer switch and 'nohidden'", function()
-    execute('e tmp1.vim')
-    execute('e Xtest-functional-ui-highlight.tmp.vim')
-    execute('filetype on')
-    execute('syntax manual')
-    execute('set ft=vim')
-    execute('set syntax=ON')
+    feed_command('e tmp1.vim')
+    feed_command('e Xtest-functional-ui-highlight.tmp.vim')
+    feed_command('filetype on')
+    feed_command('syntax manual')
+    feed_command('set ft=vim')
+    feed_command('set syntax=ON')
     feed('iecho 1<esc>0')
 
-    execute('set nohidden')
-    execute('w')
-    execute('bn')
-    execute('bp')
+    feed_command('set nohidden')
+    feed_command('w')
+    feed_command('bn')
+    feed_command('bp')
     screen:expect([[
       {1:^echo} 1              |
       {0:~                   }|
@@ -107,7 +107,7 @@ describe('Default highlight groups', function()
       [1] = {reverse = true, bold = true},  -- StatusLine
       [2] = {reverse = true}                -- StatusLineNC
     })
-    execute('sp', 'vsp', 'vsp')
+    feed_command('sp', 'vsp', 'vsp')
     screen:expect([[
       ^                    {2:|}                {2:|}               |
       {0:~                   }{2:|}{0:~               }{2:|}{0:~              }|
@@ -235,7 +235,7 @@ describe('Default highlight groups', function()
 
   it('can be cleared and linked to other highlight groups', function()
     screen:try_resize(53, 4)
-    execute('highlight clear ModeMsg')
+    feed_command('highlight clear ModeMsg')
     feed('i')
     screen:expect([[
       ^                                                     |
@@ -245,8 +245,8 @@ describe('Default highlight groups', function()
     ]], {[0] = {bold=true, foreground=Screen.colors.Blue},
     [1] = {bold=true}})
     feed('<esc>')
-    execute('highlight CustomHLGroup guifg=red guibg=green')
-    execute('highlight link ModeMsg CustomHLGroup')
+    feed_command('highlight CustomHLGroup guifg=red guibg=green')
+    feed_command('highlight link ModeMsg CustomHLGroup')
     feed('i')
     screen:expect([[
       ^                                                     |
@@ -259,8 +259,8 @@ describe('Default highlight groups', function()
 
   it('can be cleared by assigning NONE', function()
     screen:try_resize(53, 4)
-    execute('syn keyword TmpKeyword neovim')
-    execute('hi link TmpKeyword ErrorMsg')
+    feed_command('syn keyword TmpKeyword neovim')
+    feed_command('hi link TmpKeyword ErrorMsg')
     insert('neovim')
     screen:expect([[
       {1:neovi^m}                                               |
@@ -271,7 +271,7 @@ describe('Default highlight groups', function()
       [0] = {bold=true, foreground=Screen.colors.Blue},
       [1] = {foreground = Screen.colors.White, background = Screen.colors.Red}
     })
-    execute("hi ErrorMsg term=NONE cterm=NONE ctermfg=NONE ctermbg=NONE"
+    feed_command("hi ErrorMsg term=NONE cterm=NONE ctermfg=NONE ctermbg=NONE"
             .. " gui=NONE guifg=NONE guibg=NONE guisp=NONE")
     screen:expect([[
       neovi^m                                               |
@@ -283,8 +283,8 @@ describe('Default highlight groups', function()
 
   it('Whitespace highlight', function()
     screen:try_resize(53, 4)
-    execute('highlight NonText gui=NONE guifg=#FF0000')
-    execute('set listchars=space:.,tab:>-,trail:*,eol:¬ list')
+    feed_command('highlight NonText gui=NONE guifg=#FF0000')
+    feed_command('set listchars=space:.,tab:>-,trail:*,eol:¬ list')
     insert('   ne \t o\tv  im  ')
     screen:expect([[
       ne{0:.>----.}o{0:>-----}v{0:..}im{0:*^*¬}                             |
@@ -295,7 +295,7 @@ describe('Default highlight groups', function()
       [0] = {foreground=Screen.colors.Red},
       [1] = {foreground=Screen.colors.Blue},
     })
-    execute('highlight Whitespace gui=NONE guifg=#0000FF')
+    feed_command('highlight Whitespace gui=NONE guifg=#0000FF')
     screen:expect([[
       ne{1:.>----.}o{1:>-----}v{1:..}im{1:*^*}{0:¬}                             |
       {0:~                                                    }|
@@ -318,19 +318,19 @@ describe('guisp (special/undercurl)', function()
   end)
 
   it('can be set and is applied like foreground or background', function()
-    execute('syntax on')
-    execute('syn keyword TmpKeyword neovim')
-    execute('syn keyword TmpKeyword1 special')
-    execute('syn keyword TmpKeyword2 specialwithbg')
-    execute('syn keyword TmpKeyword3 specialwithfg')
-    execute('hi! Awesome guifg=red guibg=yellow guisp=red')
-    execute('hi! Awesome1 guisp=red')
-    execute('hi! Awesome2 guibg=yellow guisp=red')
-    execute('hi! Awesome3 guifg=red guisp=red')
-    execute('hi link TmpKeyword Awesome')
-    execute('hi link TmpKeyword1 Awesome1')
-    execute('hi link TmpKeyword2 Awesome2')
-    execute('hi link TmpKeyword3 Awesome3')
+    feed_command('syntax on')
+    feed_command('syn keyword TmpKeyword neovim')
+    feed_command('syn keyword TmpKeyword1 special')
+    feed_command('syn keyword TmpKeyword2 specialwithbg')
+    feed_command('syn keyword TmpKeyword3 specialwithfg')
+    feed_command('hi! Awesome guifg=red guibg=yellow guisp=red')
+    feed_command('hi! Awesome1 guisp=red')
+    feed_command('hi! Awesome2 guibg=yellow guisp=red')
+    feed_command('hi! Awesome3 guifg=red guisp=red')
+    feed_command('hi link TmpKeyword Awesome')
+    feed_command('hi link TmpKeyword1 Awesome1')
+    feed_command('hi link TmpKeyword2 Awesome2')
+    feed_command('hi link TmpKeyword3 Awesome3')
     insert([[
       neovim
       awesome neovim
@@ -382,8 +382,8 @@ describe("'listchars' highlight", function()
       [0] = {bold=true, foreground=Screen.colors.Blue},
       [1] = {background=Screen.colors.Grey90}
     })
-    execute('highlight clear ModeMsg')
-    execute('set cursorline')
+    feed_command('highlight clear ModeMsg')
+    feed_command('set cursorline')
     feed('i')
     screen:expect([[
       {1:^                    }|
@@ -408,7 +408,7 @@ describe("'listchars' highlight", function()
       {0:~                   }|
                           |
     ]])
-    execute('set nocursorline')
+    feed_command('set nocursorline')
     screen:expect([[
       abcdefg             |
       kkasd^f              |
@@ -432,8 +432,8 @@ describe("'listchars' highlight", function()
       ^f                   |
                           |
     ]])
-    execute('set cursorline')
-    execute('set cursorcolumn')
+    feed_command('set cursorline')
+    feed_command('set cursorcolumn')
     feed('kkiabcdefghijk<esc>hh')
     screen:expect([[
       kkasd   {1: }           |
@@ -472,11 +472,11 @@ describe("'listchars' highlight", function()
         foreground=Screen.colors.Red,
       },
     })
-    execute('highlight clear ModeMsg')
-    execute('highlight Whitespace guifg=#FF0000')
-    execute('set cursorline')
-    execute('set tabstop=8')
-    execute('set listchars=space:.,eol:¬,tab:>-,extends:>,precedes:<,trail:* list')
+    feed_command('highlight clear ModeMsg')
+    feed_command('highlight Whitespace guifg=#FF0000')
+    feed_command('set cursorline')
+    feed_command('set tabstop=8')
+    feed_command('set listchars=space:.,eol:¬,tab:>-,extends:>,precedes:<,trail:* list')
     feed('i\t abcd <cr>\t abcd <cr><esc>k')
     screen:expect([[
       {5:>-------.}abcd{5:*}{4:¬}     |
@@ -493,7 +493,7 @@ describe("'listchars' highlight", function()
       {4:~                   }|
                           |
     ]])
-    execute('set nocursorline')
+    feed_command('set nocursorline')
     screen:expect([[
       {5:^>-------.}abcd{5:*}{4:¬}     |
       {5:>-------.}abcd{5:*}{4:¬}     |
@@ -501,7 +501,7 @@ describe("'listchars' highlight", function()
       {4:~                   }|
       :set nocursorline   |
     ]])
-    execute('set nowrap')
+    feed_command('set nowrap')
     feed('ALorem ipsum dolor sit amet<ESC>0')
     screen:expect([[
       {5:^>-------.}abcd{5:.}Lorem{4:>}|
@@ -510,7 +510,7 @@ describe("'listchars' highlight", function()
       {4:~                   }|
                           |
     ]])
-    execute('set cursorline')
+    feed_command('set cursorline')
     screen:expect([[
       {2:^>-------.}{1:abcd}{2:.}{1:Lorem}{4:>}|
       {5:>-------.}abcd{5:*}{4:¬}     |
@@ -568,12 +568,12 @@ describe("'listchars' highlight", function()
         bold=true,
       },
     })
-    execute('highlight clear ModeMsg')
-    execute('highlight Whitespace guifg=#FF0000')
-    execute('set cursorline')
-    execute('set tabstop=8')
-    execute('set nowrap')
-    execute('set listchars=space:.,eol:¬,tab:>-,extends:>,precedes:<,trail:* list')
+    feed_command('highlight clear ModeMsg')
+    feed_command('highlight Whitespace guifg=#FF0000')
+    feed_command('set cursorline')
+    feed_command('set tabstop=8')
+    feed_command('set nowrap')
+    feed_command('set listchars=space:.,eol:¬,tab:>-,extends:>,precedes:<,trail:* list')
     feed('i\t abcd <cr>\t abcd Lorem ipsum dolor sit amet<cr><esc>kkk0')
     screen:expect([[
       {2:^>-------.}{1:abcd}{2:*}{3:¬}{1:     }|
@@ -615,10 +615,10 @@ describe("'listchars' highlight", function()
       [2] = {foreground=Screen.colors.Red},
       [3] = {foreground=Screen.colors.Green1},
     })
-    execute('highlight clear ModeMsg')
-    execute('highlight Whitespace guifg=#FF0000')
-    execute('highlight Error guifg=#00FF00')
-    execute('set nowrap')
+    feed_command('highlight clear ModeMsg')
+    feed_command('highlight Whitespace guifg=#FF0000')
+    feed_command('highlight Error guifg=#00FF00')
+    feed_command('set nowrap')
     feed('ia \t bc \t  <esc>')
     screen:expect([[
       a        bc      ^   |
@@ -627,7 +627,7 @@ describe("'listchars' highlight", function()
       {0:~                   }|
                           |
     ]])
-    execute('set listchars=space:.,eol:¬,tab:>-,extends:>,precedes:<,trail:* list')
+    feed_command('set listchars=space:.,eol:¬,tab:>-,extends:>,precedes:<,trail:* list')
     screen:expect([[
       a{2:.>-----.}bc{2:*>---*^*}{0:¬} |
       {0:~                   }|
@@ -635,7 +635,7 @@ describe("'listchars' highlight", function()
       {0:~                   }|
                           |
     ]])
-    execute('match Error /\\s\\+$/')
+    feed_command('match Error /\\s\\+$/')
     screen:expect([[
       a{2:.>-----.}bc{3:*>---*^*}{0:¬} |
       {0:~                   }|
diff --git a/test/functional/ui/inccommand_spec.lua b/test/functional/ui/inccommand_spec.lua
index 3b31da0397..b7a33cb64d 100644
--- a/test/functional/ui/inccommand_spec.lua
+++ b/test/functional/ui/inccommand_spec.lua
@@ -4,7 +4,7 @@ local clear = helpers.clear
 local curbufmeths = helpers.curbufmeths
 local eq = helpers.eq
 local eval = helpers.eval
-local execute = helpers.execute
+local feed_command = helpers.feed_command
 local expect = helpers.expect
 local feed = helpers.feed
 local insert = helpers.insert
@@ -21,9 +21,9 @@ local default_text = [[
 
 local function common_setup(screen, inccommand, text)
   if screen then
-    execute("syntax on")
-    execute("set nohlsearch")
-    execute("hi Substitute guifg=red guibg=yellow")
+    feed_command("syntax on")
+    feed_command("set nohlsearch")
+    feed_command("hi Substitute guifg=red guibg=yellow")
     screen:attach()
     screen:set_default_attr_ids({
       [1]  = {foreground = Screen.colors.Fuchsia},
@@ -46,7 +46,7 @@ local function common_setup(screen, inccommand, text)
     })
   end
 
-  execute("set inccommand=" .. (inccommand and inccommand or ""))
+  feed_command("set inccommand=" .. (inccommand and inccommand or ""))
 
   if text then
     insert(text)
@@ -91,8 +91,8 @@ describe(":substitute, 'inccommand' preserves", function()
     local screen = Screen.new(30,10)
     common_setup(screen, "split", "ABC")
 
-    execute("%s/AB/BA/")
-    execute("ls")
+    feed_command("%s/AB/BA/")
+    feed_command("ls")
 
     screen:expect([[
       {15:~                             }|
@@ -111,25 +111,25 @@ describe(":substitute, 'inccommand' preserves", function()
   for _, case in pairs{"", "split", "nosplit"} do
     it("various delimiters (inccommand="..case..")", function()
       insert(default_text)
-      execute("set inccommand=" .. case)
+      feed_command("set inccommand=" .. case)
 
       local delims = { '/', '#', ';', '%', ',', '@', '!', ''}
       for _,delim in pairs(delims) do
-        execute("%s"..delim.."lines"..delim.."LINES"..delim.."g")
+        feed_command("%s"..delim.."lines"..delim.."LINES"..delim.."g")
         expect([[
           Inc substitution on
           two LINES
           ]])
-        execute("undo")
+        feed_command("undo")
       end
     end)
   end
 
   for _, case in pairs{"", "split", "nosplit"} do
     it("'undolevels' (inccommand="..case..")", function()
-      execute("set undolevels=139")
-      execute("setlocal undolevels=34")
-      execute("set inccommand=" .. case)
+      feed_command("set undolevels=139")
+      feed_command("setlocal undolevels=34")
+      feed_command("set inccommand=" .. case)
       insert("as")
       feed(":%s/as/glork/<enter>")
       eq(meths.get_option('undolevels'), 139)
@@ -139,8 +139,8 @@ describe(":substitute, 'inccommand' preserves", function()
 
   for _, case in ipairs({"", "split", "nosplit"}) do
     it("empty undotree() (inccommand="..case..")", function()
-      execute("set undolevels=1000")
-      execute("set inccommand=" .. case)
+      feed_command("set undolevels=1000")
+      feed_command("set inccommand=" .. case)
       local expected_undotree = eval("undotree()")
 
       -- Start typing an incomplete :substitute command.
@@ -157,8 +157,8 @@ describe(":substitute, 'inccommand' preserves", function()
 
   for _, case in ipairs({"", "split", "nosplit"}) do
     it("undotree() with branches (inccommand="..case..")", function()
-      execute("set undolevels=1000")
-      execute("set inccommand=" .. case)
+      feed_command("set undolevels=1000")
+      feed_command("set inccommand=" .. case)
       -- Make some changes.
       feed([[isome text 1<C-\><C-N>]])
       feed([[osome text 2<C-\><C-N>]])
@@ -192,7 +192,7 @@ describe(":substitute, 'inccommand' preserves", function()
 
   for _, case in pairs{"", "split", "nosplit"} do
     it("b:changedtick (inccommand="..case..")", function()
-      execute("set inccommand=" .. case)
+      feed_command("set inccommand=" .. case)
       feed([[isome text 1<C-\><C-N>]])
       feed([[osome text 2<C-\><C-N>]])
       local expected_tick = eval("b:changedtick")
@@ -271,18 +271,18 @@ describe(":substitute, 'inccommand' preserves undo", function()
 
   local function test_sub(substring, split, redoable)
     clear()
-    execute("set inccommand=" .. split)
+    feed_command("set inccommand=" .. split)
 
     insert("1")
     feed("o2<esc>")
-    execute("undo")
+    feed_command("undo")
     feed("o3<esc>")
     if redoable then
       feed("o4<esc>")
-      execute("undo")
+      feed_command("undo")
     end
     feed(substring.. "<enter>")
-    execute("undo")
+    feed_command("undo")
 
     feed("g-")
     expect([[
@@ -297,15 +297,15 @@ describe(":substitute, 'inccommand' preserves undo", function()
 
   local function test_notsub(substring, split, redoable)
     clear()
-    execute("set inccommand=" .. split)
+    feed_command("set inccommand=" .. split)
 
     insert("1")
     feed("o2<esc>")
-    execute("undo")
+    feed_command("undo")
     feed("o3<esc>")
     if redoable then
       feed("o4<esc>")
-      execute("undo")
+      feed_command("undo")
     end
     feed(substring .. "<esc>")
 
@@ -331,7 +331,7 @@ describe(":substitute, 'inccommand' preserves undo", function()
 
   local function test_threetree(substring, split)
     clear()
-    execute("set inccommand=" .. split)
+    feed_command("set inccommand=" .. split)
 
     insert("1")
     feed("o2<esc>")
@@ -424,22 +424,22 @@ describe(":substitute, 'inccommand' preserves undo", function()
     for _, case in pairs(cases) do
       clear()
       common_setup(nil, case, default_text)
-      execute("set undolevels=0")
+      feed_command("set undolevels=0")
 
       feed("1G0")
       insert("X")
       feed(":%s/tw/MO/<esc>")
-      execute("undo")
+      feed_command("undo")
       expect(default_text)
-      execute("undo")
+      feed_command("undo")
       expect(default_text:gsub("Inc", "XInc"))
-      execute("undo")
+      feed_command("undo")
 
-      execute("%s/tw/MO/g")
+      feed_command("%s/tw/MO/g")
       expect(default_text:gsub("tw", "MO"))
-      execute("undo")
+      feed_command("undo")
       expect(default_text)
-      execute("undo")
+      feed_command("undo")
       expect(default_text:gsub("tw", "MO"))
     end
   end)
@@ -450,7 +450,7 @@ describe(":substitute, 'inccommand' preserves undo", function()
     for _, case in pairs(cases) do
       clear()
       common_setup(screen, case, default_text)
-      execute("set undolevels=1")
+      feed_command("set undolevels=1")
 
       feed("1G0")
       insert("X")
@@ -508,7 +508,7 @@ describe(":substitute, 'inccommand' preserves undo", function()
     for _, case in pairs(cases) do
       clear()
       common_setup(screen, case, default_text)
-      execute("set undolevels=2")
+      feed_command("set undolevels=2")
 
       feed("2GAx<esc>")
       feed("Ay<esc>")
@@ -601,7 +601,7 @@ describe(":substitute, 'inccommand' preserves undo", function()
       clear()
       common_setup(screen, case, default_text)
 
-      execute("set undolevels=-1")
+      feed_command("set undolevels=-1")
       feed(":%s/tw/MO/g<enter>")
       -- using execute("undo") here will result in a "Press ENTER" prompt
       feed("u")
@@ -637,7 +637,7 @@ describe(":substitute, 'inccommand' preserves undo", function()
       clear()
       common_setup(screen, case, default_text)
 
-      execute("set undolevels=-1")
+      feed_command("set undolevels=-1")
       feed("1G")
       feed("IL<esc>")
       feed(":%s/tw/MO/g<esc>")
@@ -676,7 +676,7 @@ describe(":substitute, inccommand=split", function()
   end)
 
   it("preserves 'modified' buffer flag", function()
-    execute("set nomodified")
+    feed_command("set nomodified")
     feed(":%s/tw")
     screen:expect([[
       Inc substitution on           |
@@ -825,7 +825,7 @@ describe(":substitute, inccommand=split", function()
   end)
 
   it("'hlsearch' is active, 'cursorline' is not", function()
-    execute("set hlsearch cursorline")
+    feed_command("set hlsearch cursorline")
     feed("gg")
 
     -- Assert that 'cursorline' is active.
@@ -917,7 +917,7 @@ describe(":substitute, inccommand=split", function()
     feed("gg")
     feed("2yy")
     feed("2000p")
-    execute("1,1000s/tw/BB/g")
+    feed_command("1,1000s/tw/BB/g")
 
     feed(":%s/tw/X")
     screen:expect([[
@@ -983,9 +983,9 @@ describe(":substitute, inccommand=split", function()
     -- Assert that 'inccommand' is ENABLED initially.
     eq("split", eval("&inccommand"))
     -- Set 'redrawtime' to minimal value, to ensure timeout is triggered.
-    execute("set redrawtime=1 nowrap")
+    feed_command("set redrawtime=1 nowrap")
     -- Load a big file.
-    execute("silent edit! test/functional/fixtures/bigfile.txt")
+    feed_command("silent edit! test/functional/fixtures/bigfile.txt")
     -- Start :substitute with a slow pattern.
     feed([[:%s/B.*N/x]])
     wait()
@@ -1018,7 +1018,7 @@ describe(":substitute, inccommand=split", function()
 
   it("clears preview if non-previewable command is edited #5585", function()
     -- Put a non-previewable command in history.
-    execute("echo 'foo'")
+    feed_command("echo 'foo'")
     -- Start an incomplete :substitute command.
     feed(":1,2s/t/X")
 
@@ -1079,7 +1079,7 @@ describe("inccommand=nosplit", function()
   end)
 
   it("works with :smagic, :snomagic", function()
-    execute("set hlsearch")
+    feed_command("set hlsearch")
     insert("Line *.3.* here")
 
     feed(":%smagic/3.*/X")    -- start :smagic command
@@ -1114,7 +1114,7 @@ describe("inccommand=nosplit", function()
   end)
 
   it('never shows preview buffer', function()
-    execute("set hlsearch")
+    feed_command("set hlsearch")
 
     feed(":%s/tw")
     screen:expect([[
@@ -1175,7 +1175,7 @@ describe("inccommand=nosplit", function()
 
   it("clears preview if non-previewable command is edited", function()
     -- Put a non-previewable command in history.
-    execute("echo 'foo'")
+    feed_command("echo 'foo'")
     -- Start an incomplete :substitute command.
     feed(":1,2s/t/X")
 
@@ -1224,7 +1224,7 @@ describe(":substitute, 'inccommand' with a failing expression", function()
   it('in the pattern does nothing', function()
     for _, case in pairs(cases) do
       refresh(case)
-      execute("set inccommand=" .. case)
+      feed_command("set inccommand=" .. case)
       feed(":silent! %s/tw\\(/LARD/<enter>")
       expect(default_text)
     end
@@ -1236,10 +1236,10 @@ describe(":substitute, 'inccommand' with a failing expression", function()
       local replacements = { "\\='LARD", "\\=xx_novar__xx" }
 
       for _, repl in pairs(replacements) do
-        execute("set inccommand=" .. case)
+        feed_command("set inccommand=" .. case)
         feed(":silent! %s/tw/" .. repl .. "/<enter>")
         expect(default_text:gsub("tw", ""))
-        execute("undo")
+        feed_command("undo")
       end
     end
   end)
@@ -1295,10 +1295,10 @@ describe("'inccommand' and :cnoremap", function()
 
       for i = 1, string.len(command) do
         local c = string.sub(command, i, i)
-        execute("cnoremap ".. c .. " " .. c)
+        feed_command("cnoremap ".. c .. " " .. c)
       end
 
-      execute(command)
+      feed_command(command)
       expect([[
         Inc substitution on
         two LINES
@@ -1309,7 +1309,7 @@ describe("'inccommand' and :cnoremap", function()
   it('work when mappings move the cursor', function()
     for _, case in pairs(cases) do
       refresh(case)
-      execute("cnoremap ,S LINES/<left><left><left><left><left><left>")
+      feed_command("cnoremap ,S LINES/<left><left><left><left><left><left>")
 
       feed(":%s/lines/,Sor three <enter>")
       expect([[
@@ -1317,21 +1317,21 @@ describe("'inccommand' and :cnoremap", function()
         two or three LINES
         ]])
 
-      execute("cnoremap ;S /X/<left><left><left>")
+      feed_command("cnoremap ;S /X/<left><left><left>")
       feed(":%s/;SI<enter>")
       expect([[
         Xnc substitution on
         two or three LXNES
         ]])
 
-      execute("cnoremap ,T //Y/<left><left><left>")
+      feed_command("cnoremap ,T //Y/<left><left><left>")
       feed(":%s,TX<enter>")
       expect([[
         Ync substitution on
         two or three LYNES
         ]])
 
-      execute("cnoremap ;T s//Z/<left><left><left>")
+      feed_command("cnoremap ;T s//Z/<left><left><left>")
       feed(":%;TY<enter>")
       expect([[
         Znc substitution on
@@ -1343,7 +1343,7 @@ describe("'inccommand' and :cnoremap", function()
   it('does not work with a failing mapping', function()
     for _, case in pairs(cases) do
       refresh(case)
-      execute("cnoremap <expr> x execute('bwipeout!')[-1].'x'")
+      feed_command("cnoremap <expr> x execute('bwipeout!')[-1].'x'")
 
       feed(":%s/tw/tox<enter>")
 
@@ -1356,7 +1356,7 @@ describe("'inccommand' and :cnoremap", function()
   it('work when temporarily moving the cursor', function()
     for _, case in pairs(cases) do
       refresh(case)
-      execute("cnoremap <expr> x cursor(1, 1)[-1].'x'")
+      feed_command("cnoremap <expr> x cursor(1, 1)[-1].'x'")
 
       feed(":%s/tw/tox/g<enter>")
       expect(default_text:gsub("tw", "tox"))
@@ -1366,7 +1366,7 @@ describe("'inccommand' and :cnoremap", function()
   it("work when a mapping disables 'inccommand'", function()
     for _, case in pairs(cases) do
       refresh(case)
-      execute("cnoremap <expr> x execute('set inccommand=')[-1]")
+      feed_command("cnoremap <expr> x execute('set inccommand=')[-1]")
 
       feed(":%s/tw/toxa/g<enter>")
       expect(default_text:gsub("tw", "toa"))
@@ -1440,7 +1440,7 @@ describe("'inccommand' autocommands", function()
 
   local function register_autocmd(event)
     meths.set_var(event .. "_fired", {})
-    execute("autocmd " .. event .. " * call add(g:" .. event .. "_fired, expand('<abuf>'))")
+    feed_command("autocmd " .. event .. " * call add(g:" .. event .. "_fired, expand('<abuf>'))")
   end
 
   it('are not fired when splitting', function()
@@ -1493,8 +1493,8 @@ describe("'inccommand' split windows", function()
     refresh()
 
     feed("gg")
-    execute("vsplit")
-    execute("split")
+    feed_command("vsplit")
+    feed_command("split")
     feed(":%s/tw")
     screen:expect([[
       Inc substitution on {10:|}Inc substitution on|
@@ -1530,9 +1530,9 @@ describe("'inccommand' split windows", function()
     ]])
 
     feed("<esc>")
-    execute("only")
-    execute("split")
-    execute("vsplit")
+    feed_command("only")
+    feed_command("split")
+    feed_command("vsplit")
 
     feed(":%s/tw")
     screen:expect([[
@@ -1581,7 +1581,7 @@ describe("'inccommand' split windows", function()
   it("are not affected by various settings", function()
     for _, setting in pairs(settings) do
       refresh()
-      execute("set " .. setting)
+      feed_command("set " .. setting)
 
       feed(":%s/tw")
 
diff --git a/test/functional/ui/input_spec.lua b/test/functional/ui/input_spec.lua
index cec19250d2..29d974b709 100644
--- a/test/functional/ui/input_spec.lua
+++ b/test/functional/ui/input_spec.lua
@@ -1,5 +1,5 @@
 local helpers = require('test.functional.helpers')(after_each)
-local clear, execute, nvim = helpers.clear, helpers.execute, helpers.nvim
+local clear, feed_command, nvim = helpers.clear, helpers.feed_command, helpers.nvim
 local feed, next_message, eq = helpers.feed, helpers.next_message, helpers.eq
 local expect = helpers.expect
 local Screen = require('test.functional.ui.screen')
@@ -12,7 +12,7 @@ describe('mappings', function()
   local add_mapping = function(mapping, send)
     local cmd = "nnoremap "..mapping.." :call rpcnotify("..cid..", 'mapped', '"
                 ..send:gsub('<', '<lt>').."')<cr>"
-    execute(cmd)
+    feed_command(cmd)
   end
 
   local check_mapping = function(mapping, expected)
@@ -57,7 +57,7 @@ describe('feeding large chunks of input with <Paste>', function()
     clear()
     screen = Screen.new()
     screen:attach()
-    execute('set ruler')
+    feed_command('set ruler')
   end)
 
   it('ok', function()
diff --git a/test/functional/ui/mouse_spec.lua b/test/functional/ui/mouse_spec.lua
index ecbd5642d1..35af34015d 100644
--- a/test/functional/ui/mouse_spec.lua
+++ b/test/functional/ui/mouse_spec.lua
@@ -1,7 +1,7 @@
 local helpers = require('test.functional.helpers')(after_each)
 local Screen = require('test.functional.ui.screen')
 local clear, feed, meths = helpers.clear, helpers.feed, helpers.meths
-local insert, execute = helpers.insert, helpers.execute
+local insert, feed_command = helpers.insert, helpers.feed_command
 local eq, funcs = helpers.eq, helpers.funcs
 
 if helpers.pending_win32(pending) then return end
@@ -123,9 +123,9 @@ describe('ui/mouse/input', function()
     end)
 
     it('in tabline on filler space moves tab to the end', function()
-      execute('%delete')
+      feed_command('%delete')
       insert('this is foo')
-      execute('silent file foo | tabnew | file bar')
+      feed_command('silent file foo | tabnew | file bar')
       insert('this is bar')
       screen:expect([[
         {tab: + foo }{sel: + bar }{fill:          }{tab:X}|
@@ -160,9 +160,9 @@ describe('ui/mouse/input', function()
         return
       end
 
-      execute('%delete')
+      feed_command('%delete')
       insert('this is foo')
-      execute('silent file foo | tabnew | file bar')
+      feed_command('silent file foo | tabnew | file bar')
       insert('this is bar')
       screen:expect([[
         {tab: + foo }{sel: + bar }{fill:          }{tab:X}|
@@ -190,9 +190,9 @@ describe('ui/mouse/input', function()
     end)
 
     it('in tabline to the right moves tab right', function()
-      execute('%delete')
+      feed_command('%delete')
       insert('this is foo')
-      execute('silent file foo | tabnew | file bar')
+      feed_command('silent file foo | tabnew | file bar')
       insert('this is bar')
       screen:expect([[
         {tab: + foo }{sel: + bar }{fill:          }{tab:X}|
@@ -220,9 +220,9 @@ describe('ui/mouse/input', function()
     end)
 
     it('out of tabline under filler space moves tab to the end', function()
-      execute('%delete')
+      feed_command('%delete')
       insert('this is foo')
-      execute('silent file foo | tabnew | file bar')
+      feed_command('silent file foo | tabnew | file bar')
       insert('this is bar')
       screen:expect([[
         {tab: + foo }{sel: + bar }{fill:          }{tab:X}|
@@ -265,9 +265,9 @@ describe('ui/mouse/input', function()
         return
       end
 
-      execute('%delete')
+      feed_command('%delete')
       insert('this is foo')
-      execute('silent file foo | tabnew | file bar')
+      feed_command('silent file foo | tabnew | file bar')
       insert('this is bar')
       screen:expect([[
         {tab: + foo }{sel: + bar }{fill:          }{tab:X}|
@@ -303,9 +303,9 @@ describe('ui/mouse/input', function()
     end)
 
     it('out of tabline to the right moves tab right', function()
-      execute('%delete')
+      feed_command('%delete')
       insert('this is foo')
-      execute('silent file foo | tabnew | file bar')
+      feed_command('silent file foo | tabnew | file bar')
       insert('this is bar')
       screen:expect([[
         {tab: + foo }{sel: + bar }{fill:          }{tab:X}|
@@ -352,9 +352,9 @@ describe('ui/mouse/input', function()
     end)
 
     it('left click in default tabline (position 4) switches to tab', function()
-      execute('%delete')
+      feed_command('%delete')
       insert('this is foo')
-      execute('silent file foo | tabnew | file bar')
+      feed_command('silent file foo | tabnew | file bar')
       insert('this is bar')
       screen:expect([[
         {tab: + foo }{sel: + bar }{fill:          }{tab:X}|
@@ -375,9 +375,9 @@ describe('ui/mouse/input', function()
 
     it('left click in default tabline (position 24) closes tab', function()
       meths.set_option('hidden', true)
-      execute('%delete')
+      feed_command('%delete')
       insert('this is foo')
-      execute('silent file foo | tabnew | file bar')
+      feed_command('silent file foo | tabnew | file bar')
       insert('this is bar')
       screen:expect([[
         {tab: + foo }{sel: + bar }{fill:          }{tab:X}|
@@ -398,9 +398,9 @@ describe('ui/mouse/input', function()
 
     it('double click in default tabline (position 4) opens new tab', function()
       meths.set_option('hidden', true)
-      execute('%delete')
+      feed_command('%delete')
       insert('this is foo')
-      execute('silent file foo | tabnew | file bar')
+      feed_command('silent file foo | tabnew | file bar')
       insert('this is bar')
       screen:expect([[
         {tab: + foo }{sel: + bar }{fill:          }{tab:X}|
@@ -421,13 +421,13 @@ describe('ui/mouse/input', function()
 
     describe('%@ label', function()
       before_each(function()
-        execute([[
+        feed_command([[
           function Test(...)
             let g:reply = a:000
             return copy(a:000)  " Check for memory leaks: return should be freed
           endfunction
         ]])
-        execute([[
+        feed_command([[
           function Test2(...)
             return call('Test', a:000 + [2])
           endfunction
@@ -533,9 +533,9 @@ describe('ui/mouse/input', function()
       fill = { reverse=true },
       vis  = { background=Screen.colors.LightGrey }
     })
-    execute('silent file foo | tabnew | file bar')
+    feed_command('silent file foo | tabnew | file bar')
     insert('this is bar')
-    execute('tabprevious')  -- go to first tab
+    feed_command('tabprevious')  -- go to first tab
     screen:expect([[
       {sel: + foo }{tab: + bar }{fill:          }{tab:X}|
       mouse                    |
@@ -641,7 +641,7 @@ describe('ui/mouse/input', function()
     mouse scrolling
     ]])
     screen:try_resize(53, 14)
-    execute('sp', 'vsp')
+    feed_command('sp', 'vsp')
     screen:expect([[
       lines                     {4:|}lines                     |
       to                        {4:|}to                        |
@@ -754,12 +754,12 @@ describe('ui/mouse/input', function()
       })
       feed('ggdG')
 
-      execute('set concealcursor=n')
-      execute('set nowrap')
-      execute('syntax match NonText "\\<amet\\>" conceal')
-      execute('syntax match NonText "\\cs\\|g." conceal cchar=X')
-      execute('syntax match NonText "\\%(lo\\|cl\\)." conceal')
-      execute('syntax match NonText "Lo" conceal cchar=Y')
+      feed_command('set concealcursor=n')
+      feed_command('set nowrap')
+      feed_command('syntax match NonText "\\<amet\\>" conceal')
+      feed_command('syntax match NonText "\\cs\\|g." conceal cchar=X')
+      feed_command('syntax match NonText "\\%(lo\\|cl\\)." conceal')
+      feed_command('syntax match NonText "Lo" conceal cchar=Y')
 
       insert([[
       Lorem ipsum dolor sit amet, consetetur sadipscing elitr.
@@ -770,7 +770,7 @@ describe('ui/mouse/input', function()
     end)
 
     it('(level 1) click on non-wrapped lines', function()
-      execute('let &conceallevel=1', 'echo')
+      feed_command('let &conceallevel=1', 'echo')
 
       feed('<esc><LeftMouse><0,0>')
       screen:expect([[
@@ -818,7 +818,7 @@ describe('ui/mouse/input', function()
     end) -- level 1 - non wrapped
 
     it('(level 1) click on wrapped lines', function()
-      execute('let &conceallevel=1', 'let &wrap=1', 'echo')
+      feed_command('let &conceallevel=1', 'let &wrap=1', 'echo')
 
       feed('<esc><LeftMouse><0,0>')
       screen:expect([[
@@ -867,7 +867,7 @@ describe('ui/mouse/input', function()
 
 
     it('(level 2) click on non-wrapped lines', function()
-      execute('let &conceallevel=2', 'echo')
+      feed_command('let &conceallevel=2', 'echo')
 
       feed('<esc><LeftMouse><0,0>')
       screen:expect([[
@@ -915,7 +915,7 @@ describe('ui/mouse/input', function()
     end) -- level 2 - non wrapped
 
     it('(level 2) click on wrapped lines', function()
-      execute('let &conceallevel=2', 'let &wrap=1', 'echo')
+      feed_command('let &conceallevel=2', 'let &wrap=1', 'echo')
 
       feed('<esc><LeftMouse><0,0>')
       screen:expect([[
@@ -964,7 +964,7 @@ describe('ui/mouse/input', function()
 
 
     it('(level 3) click on non-wrapped lines', function()
-      execute('let &conceallevel=3', 'echo')
+      feed_command('let &conceallevel=3', 'echo')
 
       feed('<esc><LeftMouse><0,0>')
       screen:expect([[
@@ -1012,7 +1012,7 @@ describe('ui/mouse/input', function()
     end) -- level 3 - non wrapped
 
     it('(level 3) click on wrapped lines', function()
-      execute('let &conceallevel=3', 'let &wrap=1', 'echo')
+      feed_command('let &conceallevel=3', 'let &wrap=1', 'echo')
 
       feed('<esc><LeftMouse><0,0>')
       screen:expect([[
diff --git a/test/functional/ui/quickfix_spec.lua b/test/functional/ui/quickfix_spec.lua
index 29b28fe9f0..68dc8b428c 100644
--- a/test/functional/ui/quickfix_spec.lua
+++ b/test/functional/ui/quickfix_spec.lua
@@ -1,7 +1,7 @@
 local helpers = require('test.functional.helpers')(after_each)
 local Screen = require('test.functional.ui.screen')
 local clear, feed, meths = helpers.clear, helpers.feed, helpers.meths
-local insert, execute = helpers.insert, helpers.execute
+local insert, command = helpers.insert, helpers.command
 
 
 describe('quickfix selection highlight', function()
@@ -28,8 +28,8 @@ describe('quickfix selection highlight', function()
     })
 
     meths.set_option('errorformat', '%m %l')
-    execute('syntax on')
-    execute('highlight Search guibg=Green')
+    command('syntax on')
+    command('highlight Search guibg=Green')
 
     insert([[
     Line 1
@@ -39,7 +39,7 @@ describe('quickfix selection highlight', function()
     Line 5
     ]])
 
-    execute('cad')
+    command('cad')
     feed('gg')
 
     screen:expect([[
@@ -57,7 +57,7 @@ describe('quickfix selection highlight', function()
   end)
 
   it('using default Search highlight group', function()
-    execute('copen')
+    command('copen')
 
     screen:expect([[
       Line 1                   |
@@ -72,7 +72,7 @@ describe('quickfix selection highlight', function()
       :copen                   |
     ]])
 
-    execute('cnext')
+    command('cnext')
 
     screen:expect([[
       Line 1                   |
@@ -89,9 +89,9 @@ describe('quickfix selection highlight', function()
   end)
 
   it('using QuickFixLine highlight group', function()
-    execute('highlight QuickFixLine guibg=Red')
+    command('highlight QuickFixLine guibg=Red')
 
-    execute('copen')
+    command('copen')
 
     screen:expect([[
       Line 1                   |
@@ -106,7 +106,7 @@ describe('quickfix selection highlight', function()
       :copen                   |
     ]])
 
-    execute('cnext')
+    command('cnext')
 
     screen:expect([[
       Line 1                   |
@@ -123,11 +123,11 @@ describe('quickfix selection highlight', function()
   end)
 
   it('combines with CursorLine', function()
-    execute('set cursorline')
-    execute('highlight QuickFixLine guifg=Red')
-    execute('highlight CursorLine guibg=Fuchsia')
+    command('set cursorline')
+    command('highlight QuickFixLine guifg=Red')
+    command('highlight CursorLine guibg=Fuchsia')
 
-    execute('copen')
+    command('copen')
 
     screen:expect([[
       {9:Line 1                   }|
@@ -159,11 +159,11 @@ describe('quickfix selection highlight', function()
   end)
 
   it('QuickFixLine background takes precedence over CursorLine', function()
-    execute('set cursorline')
-    execute('highlight QuickFixLine guibg=Red')
-    execute('highlight CursorLine guibg=Fuchsia')
+    command('set cursorline')
+    command('highlight QuickFixLine guibg=Red')
+    command('highlight CursorLine guibg=Fuchsia')
 
-    execute('copen')
+    command('copen')
 
     screen:expect([[
       {9:Line 1                   }|
diff --git a/test/functional/ui/screen_basic_spec.lua b/test/functional/ui/screen_basic_spec.lua
index 21953ba294..377923eaa4 100644
--- a/test/functional/ui/screen_basic_spec.lua
+++ b/test/functional/ui/screen_basic_spec.lua
@@ -1,7 +1,7 @@
 local helpers = require('test.functional.helpers')(after_each)
 local Screen = require('test.functional.ui.screen')
 local spawn, set_session, clear = helpers.spawn, helpers.set_session, helpers.clear
-local feed, execute = helpers.feed, helpers.execute
+local feed, command = helpers.feed, helpers.command
 local insert = helpers.insert
 local eq = helpers.eq
 local eval = helpers.eval
@@ -75,7 +75,7 @@ describe('Screen', function()
       local function check()
         eq(true, screen.suspended)
       end
-      execute('suspend')
+      command('suspend')
       screen:expect(check)
       screen.suspended = false
       feed('<c-z>')
@@ -91,7 +91,7 @@ describe('Screen', function()
         eq(false, screen.visual_bell)
       end)
       screen.bell = false
-      execute('set visualbell')
+      command('set visualbell')
       feed('<left>')
       screen:expect(function()
         eq(true, screen.visual_bell)
@@ -103,8 +103,8 @@ describe('Screen', function()
   describe(':set title', function()
     it('is forwarded to the UI', function()
       local expected = 'test-title'
-      execute('set titlestring='..expected)
-      execute('set title')
+      command('set titlestring='..expected)
+      command('set title')
       screen:expect(function()
         eq(expected, screen.title)
       end)
@@ -112,7 +112,7 @@ describe('Screen', function()
 
     it('has correct default title with unnamed file', function()
       local expected = '[No Name] - NVIM'
-      execute('set title')
+      command('set title')
       screen:expect(function()
         eq(expected, screen.title)
       end)
@@ -120,8 +120,8 @@ describe('Screen', function()
 
     it('has correct default title with named file', function()
       local expected = 'myfile (/mydir) - NVIM'
-      execute('set title')
-      execute('file /mydir/myfile')
+      command('set title')
+      command('file /mydir/myfile')
       screen:expect(function()
         eq(expected, screen.title)
       end)
@@ -131,8 +131,8 @@ describe('Screen', function()
   describe(':set icon', function()
     it('is forwarded to the UI', function()
       local expected = 'test-icon'
-      execute('set iconstring='..expected)
-      execute('set icon')
+      command('set iconstring='..expected)
+      command('set icon')
       screen:expect(function()
         eq(expected, screen.icon)
       end)
@@ -142,7 +142,7 @@ describe('Screen', function()
   describe('window', function()
     describe('split', function()
       it('horizontal', function()
-        execute('sp')
+        command('sp')
         screen:expect([[
           ^                                                     |
           {0:~                                                    }|
@@ -162,8 +162,8 @@ describe('Screen', function()
       end)
 
       it('horizontal and resize', function()
-        execute('sp')
-        execute('resize 8')
+        command('sp')
+        command('resize 8')
         screen:expect([[
           ^                                                     |
           {0:~                                                    }|
@@ -183,7 +183,9 @@ describe('Screen', function()
       end)
 
       it('horizontal and vertical', function()
-        execute('sp', 'vsp', 'vsp')
+        command('sp')
+        command('vsp')
+        command('vsp')
         screen:expect([[
           ^                    {3:|}                {3:|}               |
           {0:~                   }{3:|}{0:~               }{3:|}{0:~              }|
@@ -223,7 +225,9 @@ describe('Screen', function()
 
   describe('tabnew', function()
     it('creates a new buffer', function()
-      execute('sp', 'vsp', 'vsp')
+      command('sp')
+      command('vsp')
+      command('vsp')
       insert('hello')
       screen:expect([[
         hell^o               {3:|}hello           {3:|}hello          |
@@ -241,7 +245,7 @@ describe('Screen', function()
         {3:[No Name] [+]                                        }|
                                                              |
       ]])
-      execute('tabnew')
+      command('tabnew')
       insert('hello2')
       feed('h')
       screen:expect([[
@@ -260,7 +264,7 @@ describe('Screen', function()
         {0:~                                                    }|
                                                              |
       ]])
-      execute('tabprevious')
+      command('tabprevious')
       screen:expect([[
         {2: }{6:4}{2:+ [No Name] }{4: + [No Name] }{3:                         }{4:X}|
         hell^o               {3:|}hello           {3:|}hello          |
@@ -305,9 +309,9 @@ describe('Screen', function()
   describe('normal mode', function()
     -- https://code.google.com/p/vim/issues/detail?id=339
     it("setting 'ruler' doesn't reset the preferred column", function()
-      execute('set virtualedit=')
+      command('set virtualedit=')
       feed('i0123456<cr>789<esc>kllj')
-      execute('set ruler')
+      command('set ruler')
       feed('k')
       screen:expect([[
         0123^456                                              |
@@ -388,7 +392,9 @@ describe('Screen', function()
       split
       windows
       ]])
-      execute('sp', 'vsp', 'vsp')
+      command('sp')
+      command('vsp')
+      command('vsp')
       screen:expect([[
         and                 {3:|}and             {3:|}and            |
         clearing            {3:|}clearing        {3:|}clearing       |
diff --git a/test/functional/ui/searchhl_spec.lua b/test/functional/ui/searchhl_spec.lua
index 3914648e8f..11b18d015f 100644
--- a/test/functional/ui/searchhl_spec.lua
+++ b/test/functional/ui/searchhl_spec.lua
@@ -1,7 +1,7 @@
 local helpers = require('test.functional.helpers')(after_each)
 local Screen = require('test.functional.ui.screen')
 local clear, feed, insert = helpers.clear, helpers.feed, helpers.insert
-local execute = helpers.execute
+local feed_command = helpers.feed_command
 
 if helpers.pending_win32(pending) then return end
 
@@ -22,7 +22,7 @@ describe('search highlighting', function()
   end)
 
   it('is disabled by ":set nohlsearch"', function()
-    execute('set nohlsearch')
+    feed_command('set nohlsearch')
     insert("some text\nmore text")
     feed("gg/text<cr>")
     screen:expect([[
@@ -79,7 +79,7 @@ describe('search highlighting', function()
       /\<text\>                               |
     ]])
 
-    execute("nohlsearch")
+    feed_command("nohlsearch")
     screen:expect([[
         some text                             |
         more textstuff                        |
@@ -92,8 +92,8 @@ describe('search highlighting', function()
   end)
 
   it('works with incsearch', function()
-    execute('set hlsearch')
-    execute('set incsearch')
+    feed_command('set hlsearch')
+    feed_command('set incsearch')
     insert([[
       the first line
       in a little file
@@ -156,8 +156,8 @@ describe('search highlighting', function()
   end)
 
   it('works with incsearch and offset', function()
-    execute('set hlsearch')
-    execute('set incsearch')
+    feed_command('set hlsearch')
+    feed_command('set incsearch')
     insert([[
       not the match you're looking for
       the match is here]])
@@ -198,7 +198,7 @@ describe('search highlighting', function()
   end)
 
   it('works with multiline regexps', function()
-    execute('set hlsearch')
+    feed_command('set hlsearch')
     feed('4oa  repeated line<esc>')
     feed('/line\\na<cr>')
     screen:expect([[
@@ -234,19 +234,19 @@ describe('search highlighting', function()
         [6] = {italic = true, background = colors.Magenta},
         [7] = {bold = true, background = colors.Yellow},
     } )
-    execute('set hlsearch')
+    feed_command('set hlsearch')
     insert([[
       very special text
     ]])
-    execute("syntax on")
-    execute("highlight MyGroup guibg=Green gui=bold")
-    execute("highlight MyGroup2 guibg=Magenta gui=italic")
-    execute("call matchadd('MyGroup', 'special')")
-    execute("call matchadd('MyGroup2', 'text', 0)")
+    feed_command("syntax on")
+    feed_command("highlight MyGroup guibg=Green gui=bold")
+    feed_command("highlight MyGroup2 guibg=Magenta gui=italic")
+    feed_command("call matchadd('MyGroup', 'special')")
+    feed_command("call matchadd('MyGroup2', 'text', 0)")
 
     -- searchhl and matchadd matches are exclusive, only the higest priority
     -- is used (and matches with lower priorities are not combined)
-    execute("/ial te")
+    feed_command("/ial te")
     screen:expect([[
         very {5:spec^ial}{2: te}{6:xt}                     |
                                               |
@@ -257,7 +257,7 @@ describe('search highlighting', function()
       {4:search hit BOTTOM, continuing at TOP}    |
     ]])
 
-    execute("call clearmatches()")
+    feed_command("call clearmatches()")
     screen:expect([[
         very spec{2:^ial te}xt                     |
                                               |
@@ -270,7 +270,7 @@ describe('search highlighting', function()
 
     -- searchhl has priority over syntax, but in this case
     -- nonconflicting attributes are combined
-    execute("syntax keyword MyGroup special")
+    feed_command("syntax keyword MyGroup special")
     screen:expect([[
         very {5:spec}{7:^ial}{2: te}xt                     |
                                               |
diff --git a/test/functional/ui/sign_spec.lua b/test/functional/ui/sign_spec.lua
index d02fc83809..becd56a92a 100644
--- a/test/functional/ui/sign_spec.lua
+++ b/test/functional/ui/sign_spec.lua
@@ -1,6 +1,6 @@
 local helpers = require('test.functional.helpers')(after_each)
 local Screen = require('test.functional.ui.screen')
-local clear, feed, execute = helpers.clear, helpers.feed, helpers.execute
+local clear, feed, command = helpers.clear, helpers.feed, helpers.command
 
 if helpers.pending_win32(pending) then return end
 
@@ -25,11 +25,11 @@ describe('Signs', function()
   describe(':sign place', function()
     it('shadows previously placed signs', function()
       feed('ia<cr>b<cr>c<cr><esc>')
-      execute('sign define piet text=>> texthl=Search')
-      execute('sign define pietx text=>! texthl=Search')
-      execute('sign place 1 line=1 name=piet buffer=1')
-      execute('sign place 2 line=3 name=piet buffer=1')
-      execute('sign place 3 line=1 name=pietx buffer=1')
+      command('sign define piet text=>> texthl=Search')
+      command('sign define pietx text=>! texthl=Search')
+      command('sign place 1 line=1 name=piet buffer=1')
+      command('sign place 2 line=3 name=piet buffer=1')
+      command('sign place 3 line=1 name=pietx buffer=1')
       screen:expect([[
         {1:>!}a                                                  |
         {2:  }b                                                  |
diff --git a/test/functional/ui/syntax_conceal_spec.lua b/test/functional/ui/syntax_conceal_spec.lua
index ee3e4fa32a..991443a2ea 100644
--- a/test/functional/ui/syntax_conceal_spec.lua
+++ b/test/functional/ui/syntax_conceal_spec.lua
@@ -1,6 +1,6 @@
 local helpers = require('test.functional.helpers')(after_each)
 local Screen = require('test.functional.ui.screen')
-local clear, feed, execute = helpers.clear, helpers.feed, helpers.execute
+local clear, feed, command = helpers.clear, helpers.feed, helpers.command
 local insert = helpers.insert
 
 if helpers.pending_win32(pending) then return end
@@ -25,7 +25,7 @@ describe('Screen', function()
   describe("match and conceal", function()
 
     before_each(function()
-      execute("let &conceallevel=1")
+      command("let &conceallevel=1")
     end)
 
     describe("multiple", function()
@@ -38,7 +38,7 @@ describe('Screen', function()
           &&
           &&
           ]])
-        execute("syn match dAmpersand '[&][&]' conceal cchar=∧")
+        command("syn match dAmpersand '[&][&]' conceal cchar=∧")
       end)
 
       it("double characters.", function()
@@ -123,8 +123,8 @@ describe('Screen', function()
 
     it("keyword instances in initially in the document.", function()
       feed("2ilambda<cr><ESC>")
-      execute("let &conceallevel=1")
-      execute("syn keyword kLambda lambda conceal cchar=λ")
+      command("let &conceallevel=1")
+      command("syn keyword kLambda lambda conceal cchar=λ")
       screen:expect([[
         {1:λ}                                                    |
         {1:λ}                                                    |
@@ -144,11 +144,11 @@ describe('Screen', function()
       before_each(function()
         feed("2")
         insert("<r> a region of text </r>\n")
-        execute("let &conceallevel=1")
+        command("let &conceallevel=1")
       end)
 
       it('initially and conceal it.', function()
-        execute("syn region rText start='<r>' end='</r>' conceal cchar=R")
+        command("syn region rText start='<r>' end='</r>' conceal cchar=R")
         screen:expect([[
           {1:R}                                                    |
           {1:R}                                                    |
@@ -166,7 +166,7 @@ describe('Screen', function()
       it('initially and conceal its start tag and end tag.', function()
         -- concealends has a known bug (todo.txt) where the first match won't
         -- be replaced with cchar.
-        execute("syn region rText matchgroup=rMatch start='<r>' end='</r>' concealends cchar=-")
+        command("syn region rText matchgroup=rMatch start='<r>' end='</r>' concealends cchar=-")
         screen:expect([[
           {1: } a region of text {1:-}                                 |
           {1: } a region of text {1:-}                                 |
@@ -182,7 +182,7 @@ describe('Screen', function()
       end)
 
       it('that are nested and conceal the nested region\'s start and end tags.', function()
-        execute("syn region rText contains=rText matchgroup=rMatch start='<r>' end='</r>' concealends cchar=-")
+        command("syn region rText contains=rText matchgroup=rMatch start='<r>' end='</r>' concealends cchar=-")
         insert("<r> A region with <r> a nested <r> nested region.</r> </r> </r>\n")
         screen:expect([[
           {1: } a region of text {1:-}                                 |
@@ -201,10 +201,10 @@ describe('Screen', function()
 
     describe("a region of text", function()
       before_each(function()
-        execute("syntax conceal on")
+        command("syntax conceal on")
         feed("2")
         insert("<r> a region of text </r>\n")
-        execute("syn region rText start='<r>' end='</r>' cchar=-")
+        command("syn region rText start='<r>' end='</r>' cchar=-")
       end)
 
       it("and turn on implicit concealing", function()
@@ -223,10 +223,10 @@ describe('Screen', function()
       end)
 
       it("and then turn on, then off, and then back on implicit concealing.", function()
-        execute("syntax conceal off")
+        command("syntax conceal off")
         feed("2")
         insert("<i> italian text </i>\n")
-        execute("syn region iText start='<i>' end='</i>' cchar=*")
+        command("syn region iText start='<i>' end='</i>' cchar=*")
         screen:expect([[
           {1:-}                                                    |
           {1:-}                                                    |
@@ -239,8 +239,8 @@ describe('Screen', function()
           {0:~                                                    }|
           :syn region iText start='<i>' end='</i>' cchar=*     |
         ]])
-        execute("syntax conceal on")
-        execute("syn region iText start='<i>' end='</i>' cchar=*")
+        command("syntax conceal on")
+        command("syn region iText start='<i>' end='</i>' cchar=*")
         screen:expect([[
           {1:-}                                                    |
           {1:-}                                                    |
@@ -262,13 +262,13 @@ describe('Screen', function()
       insert("// No Conceal\n")
       insert('"Conceal without a cchar"\n')
       insert("+ With cchar\n\n")
-      execute("syn match noConceal '^//.*$'")
-      execute("syn match concealNoCchar '\".\\{-}\"$' conceal")
-      execute("syn match concealWCchar '^+.\\{-}$' conceal cchar=C")
+      command("syn match noConceal '^//.*$'")
+      command("syn match concealNoCchar '\".\\{-}\"$' conceal")
+      command("syn match concealWCchar '^+.\\{-}$' conceal cchar=C")
     end)
 
     it("0. No concealing.", function()
-      execute("let &conceallevel=0")
+      command("let &conceallevel=0")
       screen:expect([[
         // No Conceal                                        |
         "Conceal without a cchar"                            |
@@ -284,7 +284,7 @@ describe('Screen', function()
     end)
 
     it("1. Conceal using cchar or reference listchars.", function()
-      execute("let &conceallevel=1")
+      command("let &conceallevel=1")
       screen:expect([[
         // No Conceal                                        |
         {1: }                                                    |
@@ -300,7 +300,7 @@ describe('Screen', function()
     end)
 
     it("2. Hidden unless cchar is set.", function()
-      execute("let &conceallevel=2")
+      command("let &conceallevel=2")
       screen:expect([[
         // No Conceal                                        |
                                                              |
@@ -316,7 +316,7 @@ describe('Screen', function()
     end)
 
     it("3. Hide all concealed text.", function()
-      execute("let &conceallevel=3")
+      command("let &conceallevel=3")
       screen:expect([[
         // No Conceal                                        |
                                                              |
diff --git a/test/functional/ui/wildmode_spec.lua b/test/functional/ui/wildmode_spec.lua
index 6a6dc99c3d..6639bf272d 100644
--- a/test/functional/ui/wildmode_spec.lua
+++ b/test/functional/ui/wildmode_spec.lua
@@ -1,6 +1,6 @@
 local helpers = require('test.functional.helpers')(after_each)
 local Screen = require('test.functional.ui.screen')
-local clear, feed, execute = helpers.clear, helpers.feed, helpers.execute
+local clear, feed, command = helpers.clear, helpers.feed, helpers.command
 local funcs = helpers.funcs
 
 if helpers.pending_win32(pending) then return end
@@ -20,8 +20,8 @@ describe("'wildmode'", function()
 
   describe("'wildmenu'", function()
     it(':sign <tab> shows wildmenu completions', function()
-      execute('set wildmode=full')
-      execute('set wildmenu')
+      command('set wildmode=full')
+      command('set wildmenu')
       feed(':sign <tab>')
       screen:expect([[
                                  |
@@ -50,10 +50,10 @@ describe('command line completion', function()
 
   it('lists directories with empty PATH', function()
     local tmp = funcs.tempname()
-    execute('e '.. tmp)
-    execute('cd %:h')
-    execute("call mkdir('Xtest-functional-viml-compl-dir')")
-    execute('let $PATH=""')
+    command('e '.. tmp)
+    command('cd %:h')
+    command("call mkdir('Xtest-functional-viml-compl-dir')")
+    command('let $PATH=""')
     feed(':!<tab><bs>')
     screen:expect([[
                                               |