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.

10 files changed, 172 insertions, 171 deletions

diff --git a/test/functional/eval/api_functions_spec.lua b/test/functional/eval/api_functions_spec.lua
index 21dd228145..7f6f53d226 100644
--- a/test/functional/eval/api_functions_spec.lua
+++ b/test/functional/eval/api_functions_spec.lua
@@ -1,7 +1,7 @@
 local helpers = require('test.functional.helpers')(after_each)
 local Screen = require('test.functional.ui.screen')
 local lfs = require('lfs')
-local neq, eq, execute = helpers.neq, helpers.eq, helpers.execute
+local neq, eq, command = helpers.neq, helpers.eq, helpers.command
 local clear, curbufmeths = helpers.clear, helpers.curbufmeths
 local exc_exec, expect, eval = helpers.exc_exec, helpers.expect, helpers.eval
 local insert = helpers.insert
@@ -10,17 +10,17 @@ describe('api functions', function()
   before_each(clear)
 
   it("work", function()
-    execute("call nvim_command('let g:test = 1')")
+    command("call nvim_command('let g:test = 1')")
     eq(1, eval("nvim_get_var('test')"))
 
     local buf = eval("nvim_get_current_buf()")
-    execute("call nvim_buf_set_lines("..buf..", 0, -1, v:true, ['aa', 'bb'])")
+    command("call nvim_buf_set_lines("..buf..", 0, -1, v:true, ['aa', 'bb'])")
     expect([[
       aa
       bb]])
 
-    execute("call nvim_win_set_cursor(0, [1, 1])")
-    execute("call nvim_input('ax<esc>')")
+    command("call nvim_win_set_cursor(0, [1, 1])")
+    command("call nvim_input('ax<esc>')")
     expect([[
       aax
       bb]])
@@ -57,7 +57,7 @@ describe('api functions', function()
     eq(bnr, bhnd)
     eq(wid, whnd)
 
-    execute("new") -- creates new buffer and new window
+    command("new") -- creates new buffer and new window
     local bnr2 = eval("bufnr('')")
     local bhnd2 = eval("nvim_get_current_buf()")
     local wid2 = eval("win_getid()")
@@ -69,7 +69,7 @@ describe('api functions', function()
     -- 0 is synonymous to the current buffer
     eq(bnr2, eval("nvim_buf_get_number(0)"))
 
-    execute("bn") -- show old buffer in new window
+    command("bn") -- show old buffer in new window
     eq(bnr, eval("nvim_get_current_buf()"))
     eq(bnr, eval("bufnr('')"))
     eq(bnr, eval("nvim_buf_get_number(0)"))
@@ -81,7 +81,7 @@ describe('api functions', function()
     curbufmeths.set_lines(0, -1, true, {"aa\0", "b\0b"})
     eq({'aa\n', 'b\nb'}, eval("nvim_buf_get_lines(0, 0, -1, 1)"))
 
-    execute('call nvim_buf_set_lines(0, 1, 2, v:true, ["xx", "\\nyy"])')
+    command('call nvim_buf_set_lines(0, 1, 2, v:true, ["xx", "\\nyy"])')
     eq({'aa\0', 'xx', '\0yy'}, curbufmeths.get_lines(0, -1, 1))
   end)
 
@@ -124,9 +124,9 @@ describe('api functions', function()
       [5] = {bold = true, foreground = Screen.colors.Blue},
     })
 
-    execute("set ft=vim")
-    execute("let &rtp='build/runtime/,'.&rtp")
-    execute("syntax on")
+    command("set ft=vim")
+    command("let &rtp='build/runtime/,'.&rtp")
+    command("syntax on")
     insert([[
       call bufnr('%')
       call nvim_input('typing...')
diff --git a/test/functional/eval/glob_spec.lua b/test/functional/eval/glob_spec.lua
index 599b3dcdc3..b8807ecfcc 100644
--- a/test/functional/eval/glob_spec.lua
+++ b/test/functional/eval/glob_spec.lua
@@ -1,13 +1,13 @@
 local lfs = require('lfs')
 local helpers = require('test.functional.helpers')(after_each)
-local clear, execute, eval, eq = helpers.clear, helpers.execute, helpers.eval, helpers.eq
+local clear, command, eval, eq = helpers.clear, helpers.command, helpers.eval, helpers.eq
 
 before_each(function()
   clear()
   lfs.mkdir('test-glob')
 
   -- Long path might cause "Press ENTER" prompt; use :silent to avoid it.
-  execute('silent cd test-glob')
+  command('silent cd test-glob')
 end)
 
 after_each(function()
diff --git a/test/functional/eval/json_functions_spec.lua b/test/functional/eval/json_functions_spec.lua
index fc0a19bdfa..4d34cde849 100644
--- a/test/functional/eval/json_functions_spec.lua
+++ b/test/functional/eval/json_functions_spec.lua
@@ -4,16 +4,17 @@ local funcs = helpers.funcs
 local meths = helpers.meths
 local eq = helpers.eq
 local eval = helpers.eval
-local execute = helpers.execute
+local command = helpers.command
 local exc_exec = helpers.exc_exec
 local redir_exec = helpers.redir_exec
 local NIL = helpers.NIL
+local source = helpers.source
 
 describe('json_decode() function', function()
   local restart = function(...)
     clear(...)
-    execute('language C')
-    execute([[
+    source([[
+      language C
       function Eq(exp, act)
         let act = a:act
         let exp = a:exp
@@ -45,8 +46,6 @@ describe('json_decode() function', function()
         endif
         return 1
       endfunction
-    ]])
-    execute([[
       function EvalEq(exp, act_expr)
         let act = eval(a:act_expr)
         if Eq(a:exp, act)
@@ -441,7 +440,7 @@ describe('json_decode() function', function()
   local sp_decode_eq = function(expected, json)
     meths.set_var('__json', json)
     speq(expected, 'json_decode(g:__json)')
-    execute('unlet! g:__json')
+    command('unlet! g:__json')
   end
 
   it('parses strings with NUL properly', function()
@@ -527,7 +526,7 @@ end)
 describe('json_encode() function', function()
   before_each(function()
     clear()
-    execute('language C')
+    command('language C')
   end)
 
   it('dumps strings', function()
@@ -576,94 +575,94 @@ describe('json_encode() function', function()
 
   it('cannot dump generic mapping with generic mapping keys and values',
   function()
-    execute('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": []}')
-    execute('let todumpv1 = {"_TYPE": v:msgpack_types.map, "_VAL": []}')
-    execute('let todumpv2 = {"_TYPE": v:msgpack_types.map, "_VAL": []}')
-    execute('call add(todump._VAL, [todumpv1, todumpv2])')
+    command('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": []}')
+    command('let todumpv1 = {"_TYPE": v:msgpack_types.map, "_VAL": []}')
+    command('let todumpv2 = {"_TYPE": v:msgpack_types.map, "_VAL": []}')
+    command('call add(todump._VAL, [todumpv1, todumpv2])')
     eq('Vim(call):E474: Invalid key in special dictionary', exc_exec('call json_encode(todump)'))
   end)
 
   it('cannot dump generic mapping with ext key', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.ext, "_VAL": [5, ["",""]]}')
-    execute('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": [[todump, 1]]}')
+    command('let todump = {"_TYPE": v:msgpack_types.ext, "_VAL": [5, ["",""]]}')
+    command('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": [[todump, 1]]}')
     eq('Vim(call):E474: Invalid key in special dictionary', exc_exec('call json_encode(todump)'))
   end)
 
   it('cannot dump generic mapping with array key', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.array, "_VAL": [5, [""]]}')
-    execute('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": [[todump, 1]]}')
+    command('let todump = {"_TYPE": v:msgpack_types.array, "_VAL": [5, [""]]}')
+    command('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": [[todump, 1]]}')
     eq('Vim(call):E474: Invalid key in special dictionary', exc_exec('call json_encode(todump)'))
   end)
 
   it('cannot dump generic mapping with UINT64_MAX key', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.integer}')
-    execute('let todump._VAL = [1, 3, 0x7FFFFFFF, 0x7FFFFFFF]')
-    execute('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": [[todump, 1]]}')
+    command('let todump = {"_TYPE": v:msgpack_types.integer}')
+    command('let todump._VAL = [1, 3, 0x7FFFFFFF, 0x7FFFFFFF]')
+    command('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": [[todump, 1]]}')
     eq('Vim(call):E474: Invalid key in special dictionary', exc_exec('call json_encode(todump)'))
   end)
 
   it('cannot dump generic mapping with floating-point key', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.float, "_VAL": 0.125}')
-    execute('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": [[todump, 1]]}')
+    command('let todump = {"_TYPE": v:msgpack_types.float, "_VAL": 0.125}')
+    command('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": [[todump, 1]]}')
     eq('Vim(call):E474: Invalid key in special dictionary', exc_exec('call json_encode(todump)'))
   end)
 
   it('can dump generic mapping with STR special key and NUL', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.string, "_VAL": ["\\n"]}')
-    execute('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": [[todump, 1]]}')
+    command('let todump = {"_TYPE": v:msgpack_types.string, "_VAL": ["\\n"]}')
+    command('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": [[todump, 1]]}')
     eq('{"\\u0000": 1}', eval('json_encode(todump)'))
   end)
 
   it('can dump generic mapping with BIN special key and NUL', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.binary, "_VAL": ["\\n"]}')
-    execute('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": [[todump, 1]]}')
+    command('let todump = {"_TYPE": v:msgpack_types.binary, "_VAL": ["\\n"]}')
+    command('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": [[todump, 1]]}')
     eq('{"\\u0000": 1}', eval('json_encode(todump)'))
   end)
 
   it('can dump STR special mapping with NUL and NL', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.string, "_VAL": ["\\n", ""]}')
+    command('let todump = {"_TYPE": v:msgpack_types.string, "_VAL": ["\\n", ""]}')
     eq('"\\u0000\\n"', eval('json_encode(todump)'))
   end)
 
   it('can dump BIN special mapping with NUL and NL', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.binary, "_VAL": ["\\n", ""]}')
+    command('let todump = {"_TYPE": v:msgpack_types.binary, "_VAL": ["\\n", ""]}')
     eq('"\\u0000\\n"', eval('json_encode(todump)'))
   end)
 
   it('cannot dump special ext mapping', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.ext, "_VAL": [5, ["",""]]}')
+    command('let todump = {"_TYPE": v:msgpack_types.ext, "_VAL": [5, ["",""]]}')
     eq('Vim(call):E474: Unable to convert EXT string to JSON', exc_exec('call json_encode(todump)'))
   end)
 
   it('can dump special array mapping', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.array, "_VAL": [5, [""]]}')
+    command('let todump = {"_TYPE": v:msgpack_types.array, "_VAL": [5, [""]]}')
     eq('[5, [""]]', eval('json_encode(todump)'))
   end)
 
   it('can dump special UINT64_MAX mapping', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.integer}')
-    execute('let todump._VAL = [1, 3, 0x7FFFFFFF, 0x7FFFFFFF]')
+    command('let todump = {"_TYPE": v:msgpack_types.integer}')
+    command('let todump._VAL = [1, 3, 0x7FFFFFFF, 0x7FFFFFFF]')
     eq('18446744073709551615', eval('json_encode(todump)'))
   end)
 
   it('can dump special INT64_MIN mapping', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.integer}')
-    execute('let todump._VAL = [-1, 2, 0, 0]')
+    command('let todump = {"_TYPE": v:msgpack_types.integer}')
+    command('let todump._VAL = [-1, 2, 0, 0]')
     eq('-9223372036854775808', eval('json_encode(todump)'))
   end)
 
   it('can dump special BOOLEAN true mapping', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.boolean, "_VAL": 1}')
+    command('let todump = {"_TYPE": v:msgpack_types.boolean, "_VAL": 1}')
     eq('true', eval('json_encode(todump)'))
   end)
 
   it('can dump special BOOLEAN false mapping', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.boolean, "_VAL": 0}')
+    command('let todump = {"_TYPE": v:msgpack_types.boolean, "_VAL": 0}')
     eq('false', eval('json_encode(todump)'))
   end)
 
   it('can dump special NIL mapping', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.nil, "_VAL": 0}')
+    command('let todump = {"_TYPE": v:msgpack_types.nil, "_VAL": 0}')
     eq('null', eval('json_encode(todump)'))
   end)
 
@@ -673,7 +672,7 @@ describe('json_encode() function', function()
   end)
 
   it('fails to dump a partial', function()
-    execute('function T() dict\nendfunction')
+    command('function T() dict\nendfunction')
     eq('Vim(call):E474: Error while dumping encode_tv2json() argument, itself: attempt to dump function reference',
        exc_exec('call json_encode(function("T", [1, 2], {}))'))
   end)
@@ -684,56 +683,56 @@ describe('json_encode() function', function()
   end)
 
   it('fails to dump a recursive list', function()
-    execute('let todump = [[[]]]')
-    execute('call add(todump[0][0], todump)')
+    command('let todump = [[[]]]')
+    command('call add(todump[0][0], todump)')
     eq('Vim(call):E724: unable to correctly dump variable with self-referencing container',
        exc_exec('call json_encode(todump)'))
   end)
 
   it('fails to dump a recursive dict', function()
-    execute('let todump = {"d": {"d": {}}}')
-    execute('call extend(todump.d.d, {"d": todump})')
+    command('let todump = {"d": {"d": {}}}')
+    command('call extend(todump.d.d, {"d": todump})')
     eq('Vim(call):E724: unable to correctly dump variable with self-referencing container',
        exc_exec('call json_encode([todump])'))
   end)
 
   it('can dump dict with two same dicts inside', function()
-    execute('let inter = {}')
-    execute('let todump = {"a": inter, "b": inter}')
+    command('let inter = {}')
+    command('let todump = {"a": inter, "b": inter}')
     eq('{"a": {}, "b": {}}', eval('json_encode(todump)'))
   end)
 
   it('can dump list with two same lists inside', function()
-    execute('let inter = []')
-    execute('let todump = [inter, inter]')
+    command('let inter = []')
+    command('let todump = [inter, inter]')
     eq('[[], []]', eval('json_encode(todump)'))
   end)
 
   it('fails to dump a recursive list in a special dict', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.array, "_VAL": []}')
-    execute('call add(todump._VAL, todump)')
+    command('let todump = {"_TYPE": v:msgpack_types.array, "_VAL": []}')
+    command('call add(todump._VAL, todump)')
     eq('Vim(call):E724: unable to correctly dump variable with self-referencing container',
        exc_exec('call json_encode(todump)'))
   end)
 
   it('fails to dump a recursive (val) map in a special dict', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": []}')
-    execute('call add(todump._VAL, ["", todump])')
+    command('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": []}')
+    command('call add(todump._VAL, ["", todump])')
     eq('Vim(call):E724: unable to correctly dump variable with self-referencing container',
        exc_exec('call json_encode([todump])'))
   end)
 
   it('fails to dump a recursive (val) map in a special dict, _VAL reference', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": [["", []]]}')
-    execute('call add(todump._VAL[0][1], todump._VAL)')
+    command('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": [["", []]]}')
+    command('call add(todump._VAL[0][1], todump._VAL)')
     eq('Vim(call):E724: unable to correctly dump variable with self-referencing container',
        exc_exec('call json_encode(todump)'))
   end)
 
   it('fails to dump a recursive (val) special list in a special dict',
   function()
-    execute('let todump = {"_TYPE": v:msgpack_types.array, "_VAL": []}')
-    execute('call add(todump._VAL, ["", todump._VAL])')
+    command('let todump = {"_TYPE": v:msgpack_types.array, "_VAL": []}')
+    command('call add(todump._VAL, ["", todump._VAL])')
     eq('Vim(call):E724: unable to correctly dump variable with self-referencing container',
        exc_exec('call json_encode(todump)'))
   end)
diff --git a/test/functional/eval/modeline_spec.lua b/test/functional/eval/modeline_spec.lua
index 0be7210a76..c5bb798f4a 100644
--- a/test/functional/eval/modeline_spec.lua
+++ b/test/functional/eval/modeline_spec.lua
@@ -1,5 +1,5 @@
 local helpers = require('test.functional.helpers')(after_each)
-local clear, execute, write_file = helpers.clear, helpers.execute, helpers.write_file
+local clear, command, write_file = helpers.clear, helpers.command, helpers.write_file
 local eq, eval = helpers.eq, helpers.eval
 
 describe("modeline", function()
@@ -12,7 +12,7 @@ describe("modeline", function()
 
   it('does not crash with a large version number', function()
     write_file(tempfile, 'vim100000000000000000000000')
-    execute('e! ' .. tempfile)
+    command('e! ' .. tempfile)
 
     eq(2, eval('1+1'))  -- Still alive?
   end)
diff --git a/test/functional/eval/msgpack_functions_spec.lua b/test/functional/eval/msgpack_functions_spec.lua
index 44c01d2226..c5520deb73 100644
--- a/test/functional/eval/msgpack_functions_spec.lua
+++ b/test/functional/eval/msgpack_functions_spec.lua
@@ -2,7 +2,7 @@ local helpers = require('test.functional.helpers')(after_each)
 local clear = helpers.clear
 local funcs = helpers.funcs
 local eval, eq = helpers.eval, helpers.eq
-local execute = helpers.execute
+local command = helpers.command
 local nvim = helpers.nvim
 local exc_exec = helpers.exc_exec
 
@@ -331,9 +331,9 @@ describe('msgpack*() functions', function()
   obj_test('are able to dump and restore floating-point value', {0.125})
 
   it('can restore and dump UINT64_MAX', function()
-    execute('let dumped = ["\\xCF" . repeat("\\xFF", 8)]')
-    execute('let parsed = msgpackparse(dumped)')
-    execute('let dumped2 = msgpackdump(parsed)')
+    command('let dumped = ["\\xCF" . repeat("\\xFF", 8)]')
+    command('let parsed = msgpackparse(dumped)')
+    command('let dumped2 = msgpackdump(parsed)')
     eq(1, eval('type(parsed[0]) == type(0) ' ..
                '|| parsed[0]._TYPE is v:msgpack_types.integer'))
     if eval('type(parsed[0]) == type(0)') == 1 then
@@ -345,9 +345,9 @@ describe('msgpack*() functions', function()
   end)
 
   it('can restore and dump INT64_MIN', function()
-    execute('let dumped = ["\\xD3\\x80" . repeat("\\n", 7)]')
-    execute('let parsed = msgpackparse(dumped)')
-    execute('let dumped2 = msgpackdump(parsed)')
+    command('let dumped = ["\\xD3\\x80" . repeat("\\n", 7)]')
+    command('let parsed = msgpackparse(dumped)')
+    command('let dumped2 = msgpackdump(parsed)')
     eq(1, eval('type(parsed[0]) == type(0) ' ..
                '|| parsed[0]._TYPE is v:msgpack_types.integer'))
     if eval('type(parsed[0]) == type(0)') == 1 then
@@ -359,33 +359,33 @@ describe('msgpack*() functions', function()
   end)
 
   it('can restore and dump BIN string with zero byte', function()
-    execute('let dumped = ["\\xC4\\x01\\n"]')
-    execute('let parsed = msgpackparse(dumped)')
-    execute('let dumped2 = msgpackdump(parsed)')
+    command('let dumped = ["\\xC4\\x01\\n"]')
+    command('let parsed = msgpackparse(dumped)')
+    command('let dumped2 = msgpackdump(parsed)')
     eq({{_TYPE={}, _VAL={'\n'}}}, eval('parsed'))
     eq(1, eval('parsed[0]._TYPE is v:msgpack_types.binary'))
     eq(1, eval('dumped ==# dumped2'))
   end)
 
   it('can restore and dump STR string with zero byte', function()
-    execute('let dumped = ["\\xA1\\n"]')
-    execute('let parsed = msgpackparse(dumped)')
-    execute('let dumped2 = msgpackdump(parsed)')
+    command('let dumped = ["\\xA1\\n"]')
+    command('let parsed = msgpackparse(dumped)')
+    command('let dumped2 = msgpackdump(parsed)')
     eq({{_TYPE={}, _VAL={'\n'}}}, eval('parsed'))
     eq(1, eval('parsed[0]._TYPE is v:msgpack_types.string'))
     eq(1, eval('dumped ==# dumped2'))
   end)
 
   it('can restore and dump BIN string with NL', function()
-    execute('let dumped = ["\\xC4\\x01", ""]')
-    execute('let parsed = msgpackparse(dumped)')
-    execute('let dumped2 = msgpackdump(parsed)')
+    command('let dumped = ["\\xC4\\x01", ""]')
+    command('let parsed = msgpackparse(dumped)')
+    command('let dumped2 = msgpackdump(parsed)')
     eq({"\n"}, eval('parsed'))
     eq(1, eval('dumped ==# dumped2'))
   end)
 
   it('dump and restore special mapping with floating-point value', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.float, "_VAL": 0.125}')
+    command('let todump = {"_TYPE": v:msgpack_types.float, "_VAL": 0.125}')
     eq({0.125}, eval('msgpackparse(msgpackdump([todump]))'))
   end)
 end)
@@ -394,52 +394,53 @@ describe('msgpackparse() function', function()
   before_each(clear)
 
   it('restores nil as v:null', function()
-    execute('let dumped = ["\\xC0"]')
-    execute('let parsed = msgpackparse(dumped)')
+    command('let dumped = ["\\xC0"]')
+    command('let parsed = msgpackparse(dumped)')
     eq('[v:null]', eval('string(parsed)'))
   end)
 
   it('restores boolean false as v:false', function()
-    execute('let dumped = ["\\xC2"]')
-    execute('let parsed = msgpackparse(dumped)')
+    command('let dumped = ["\\xC2"]')
+    command('let parsed = msgpackparse(dumped)')
     eq({false}, eval('parsed'))
   end)
 
   it('restores boolean true as v:true', function()
-    execute('let dumped = ["\\xC3"]')
-    execute('let parsed = msgpackparse(dumped)')
+    command('let dumped = ["\\xC3"]')
+    command('let parsed = msgpackparse(dumped)')
     eq({true}, eval('parsed'))
   end)
 
   it('restores FIXSTR as special dict', function()
-    execute('let dumped = ["\\xa2ab"]')
-    execute('let parsed = msgpackparse(dumped)')
+    command('let dumped = ["\\xa2ab"]')
+    command('let parsed = msgpackparse(dumped)')
     eq({{_TYPE={}, _VAL={'ab'}}}, eval('parsed'))
     eq(1, eval('g:parsed[0]._TYPE is v:msgpack_types.string'))
   end)
 
   it('restores BIN 8 as string', function()
-    execute('let dumped = ["\\xC4\\x02ab"]')
+    command('let dumped = ["\\xC4\\x02ab"]')
     eq({'ab'}, eval('msgpackparse(dumped)'))
   end)
 
   it('restores FIXEXT1 as special dictionary', function()
-    execute('let dumped = ["\\xD4\\x10", ""]')
-    execute('let parsed = msgpackparse(dumped)')
+    command('let dumped = ["\\xD4\\x10", ""]')
+    command('let parsed = msgpackparse(dumped)')
     eq({{_TYPE={}, _VAL={0x10, {"", ""}}}}, eval('parsed'))
     eq(1, eval('g:parsed[0]._TYPE is v:msgpack_types.ext'))
   end)
 
   it('restores MAP with BIN key as special dictionary', function()
-    execute('let dumped = ["\\x81\\xC4\\x01a\\xC4\\n"]')
-    execute('let parsed = msgpackparse(dumped)')
+    command('let dumped = ["\\x81\\xC4\\x01a\\xC4\\n"]')
+    command('let parsed = msgpackparse(dumped)')
     eq({{_TYPE={}, _VAL={{'a', ''}}}}, eval('parsed'))
     eq(1, eval('g:parsed[0]._TYPE is v:msgpack_types.map'))
   end)
 
   it('restores MAP with duplicate STR keys as special dictionary', function()
-    execute('let dumped = ["\\x82\\xA1a\\xC4\\n\\xA1a\\xC4\\n"]')
-    execute('let parsed = msgpackparse(dumped)')
+    command('let dumped = ["\\x82\\xA1a\\xC4\\n\\xA1a\\xC4\\n"]')
+    -- FIXME Internal error bug
+    command('silent! let parsed = msgpackparse(dumped)')
     eq({{_TYPE={}, _VAL={ {{_TYPE={}, _VAL={'a'}}, ''},
                           {{_TYPE={}, _VAL={'a'}}, ''}}} }, eval('parsed'))
     eq(1, eval('g:parsed[0]._TYPE is v:msgpack_types.map'))
@@ -448,8 +449,8 @@ describe('msgpackparse() function', function()
   end)
 
   it('restores MAP with MAP key as special dictionary', function()
-    execute('let dumped = ["\\x81\\x80\\xC4\\n"]')
-    execute('let parsed = msgpackparse(dumped)')
+    command('let dumped = ["\\x81\\x80\\xC4\\n"]')
+    command('let parsed = msgpackparse(dumped)')
     eq({{_TYPE={}, _VAL={{{}, ''}}}}, eval('parsed'))
     eq(1, eval('g:parsed[0]._TYPE is v:msgpack_types.map'))
   end)
@@ -494,7 +495,7 @@ describe('msgpackparse() function', function()
   end)
 
   it('fails to parse a partial', function()
-    execute('function T() dict\nendfunction')
+    command('function T() dict\nendfunction')
     eq('Vim(call):E686: Argument of msgpackparse() must be a List',
        exc_exec('call msgpackparse(function("T", [1, 2], {}))'))
   end)
@@ -514,10 +515,10 @@ describe('msgpackdump() function', function()
   end)
 
   it('can dump generic mapping with generic mapping keys and values', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": []}')
-    execute('let todumpv1 = {"_TYPE": v:msgpack_types.map, "_VAL": []}')
-    execute('let todumpv2 = {"_TYPE": v:msgpack_types.map, "_VAL": []}')
-    execute('call add(todump._VAL, [todumpv1, todumpv2])')
+    command('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": []}')
+    command('let todumpv1 = {"_TYPE": v:msgpack_types.map, "_VAL": []}')
+    command('let todumpv2 = {"_TYPE": v:msgpack_types.map, "_VAL": []}')
+    command('call add(todump._VAL, [todumpv1, todumpv2])')
     eq({'\129\128\128'}, eval('msgpackdump([todump])'))
   end)
 
@@ -530,130 +531,130 @@ describe('msgpackdump() function', function()
   end)
 
   it('can v:null', function()
-    execute('let todump = v:null')
+    command('let todump = v:null')
   end)
 
   it('can dump special bool mapping (true)', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.boolean, "_VAL": 1}')
+    command('let todump = {"_TYPE": v:msgpack_types.boolean, "_VAL": 1}')
     eq({'\195'}, eval('msgpackdump([todump])'))
   end)
 
   it('can dump special bool mapping (false)', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.boolean, "_VAL": 0}')
+    command('let todump = {"_TYPE": v:msgpack_types.boolean, "_VAL": 0}')
     eq({'\194'}, eval('msgpackdump([todump])'))
   end)
 
   it('can dump special nil mapping', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.nil, "_VAL": 0}')
+    command('let todump = {"_TYPE": v:msgpack_types.nil, "_VAL": 0}')
     eq({'\192'}, eval('msgpackdump([todump])'))
   end)
 
   it('can dump special ext mapping', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.ext, "_VAL": [5, ["",""]]}')
+    command('let todump = {"_TYPE": v:msgpack_types.ext, "_VAL": [5, ["",""]]}')
     eq({'\212\005', ''}, eval('msgpackdump([todump])'))
   end)
 
   it('can dump special array mapping', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.array, "_VAL": [5, [""]]}')
+    command('let todump = {"_TYPE": v:msgpack_types.array, "_VAL": [5, [""]]}')
     eq({'\146\005\145\196\n'}, eval('msgpackdump([todump])'))
   end)
 
   it('can dump special UINT64_MAX mapping', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.integer}')
-    execute('let todump._VAL = [1, 3, 0x7FFFFFFF, 0x7FFFFFFF]')
+    command('let todump = {"_TYPE": v:msgpack_types.integer}')
+    command('let todump._VAL = [1, 3, 0x7FFFFFFF, 0x7FFFFFFF]')
     eq({'\207\255\255\255\255\255\255\255\255'}, eval('msgpackdump([todump])'))
   end)
 
   it('can dump special INT64_MIN mapping', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.integer}')
-    execute('let todump._VAL = [-1, 2, 0, 0]')
+    command('let todump = {"_TYPE": v:msgpack_types.integer}')
+    command('let todump._VAL = [-1, 2, 0, 0]')
     eq({'\211\128\n\n\n\n\n\n\n'}, eval('msgpackdump([todump])'))
   end)
 
   it('fails to dump a function reference', function()
-    execute('let Todump = function("tr")')
+    command('let Todump = function("tr")')
     eq('Vim(call):E5004: Error while dumping msgpackdump() argument, index 0, itself: attempt to dump function reference',
        exc_exec('call msgpackdump([Todump])'))
   end)
 
   it('fails to dump a partial', function()
-    execute('function T() dict\nendfunction')
-    execute('let Todump = function("T", [1, 2], {})')
+    command('function T() dict\nendfunction')
+    command('let Todump = function("T", [1, 2], {})')
     eq('Vim(call):E5004: Error while dumping msgpackdump() argument, index 0, itself: attempt to dump function reference',
        exc_exec('call msgpackdump([Todump])'))
   end)
 
   it('fails to dump a function reference in a list', function()
-    execute('let todump = [function("tr")]')
+    command('let todump = [function("tr")]')
     eq('Vim(call):E5004: Error while dumping msgpackdump() argument, index 0, index 0: attempt to dump function reference',
        exc_exec('call msgpackdump([todump])'))
   end)
 
   it('fails to dump a recursive list', function()
-    execute('let todump = [[[]]]')
-    execute('call add(todump[0][0], todump)')
+    command('let todump = [[[]]]')
+    command('call add(todump[0][0], todump)')
     eq('Vim(call):E5005: Unable to dump msgpackdump() argument, index 0: container references itself in index 0, index 0, index 0',
        exc_exec('call msgpackdump([todump])'))
   end)
 
   it('fails to dump a recursive dict', function()
-    execute('let todump = {"d": {"d": {}}}')
-    execute('call extend(todump.d.d, {"d": todump})')
+    command('let todump = {"d": {"d": {}}}')
+    command('call extend(todump.d.d, {"d": todump})')
     eq('Vim(call):E5005: Unable to dump msgpackdump() argument, index 0: container references itself in key \'d\', key \'d\', key \'d\'',
        exc_exec('call msgpackdump([todump])'))
   end)
 
   it('can dump dict with two same dicts inside', function()
-    execute('let inter = {}')
-    execute('let todump = {"a": inter, "b": inter}')
+    command('let inter = {}')
+    command('let todump = {"a": inter, "b": inter}')
     eq({"\130\161a\128\161b\128"}, eval('msgpackdump([todump])'))
   end)
 
   it('can dump list with two same lists inside', function()
-    execute('let inter = []')
-    execute('let todump = [inter, inter]')
+    command('let inter = []')
+    command('let todump = [inter, inter]')
     eq({"\146\144\144"}, eval('msgpackdump([todump])'))
   end)
 
   it('fails to dump a recursive list in a special dict', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.array, "_VAL": []}')
-    execute('call add(todump._VAL, todump)')
+    command('let todump = {"_TYPE": v:msgpack_types.array, "_VAL": []}')
+    command('call add(todump._VAL, todump)')
     eq('Vim(call):E5005: Unable to dump msgpackdump() argument, index 0: container references itself in index 0',
        exc_exec('call msgpackdump([todump])'))
   end)
 
   it('fails to dump a recursive (key) map in a special dict', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": []}')
-    execute('call add(todump._VAL, [todump, 0])')
+    command('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": []}')
+    command('call add(todump._VAL, [todump, 0])')
     eq('Vim(call):E5005: Unable to dump msgpackdump() argument, index 0: container references itself in index 1',
        exc_exec('call msgpackdump([todump])'))
   end)
 
   it('fails to dump a recursive (val) map in a special dict', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": []}')
-    execute('call add(todump._VAL, [0, todump])')
+    command('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": []}')
+    command('call add(todump._VAL, [0, todump])')
     eq('Vim(call):E5005: Unable to dump msgpackdump() argument, index 0: container references itself in key 0 at index 0 from special map',
        exc_exec('call msgpackdump([todump])'))
   end)
 
   it('fails to dump a recursive (key) map in a special dict, _VAL reference', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": [[[], []]]}')
-    execute('call add(todump._VAL[0][0], todump._VAL)')
+    command('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": [[[], []]]}')
+    command('call add(todump._VAL[0][0], todump._VAL)')
     eq('Vim(call):E5005: Unable to dump msgpackdump() argument, index 0: container references itself in key [[[[...@0], []]]] at index 0 from special map, index 0',
        exc_exec('call msgpackdump([todump])'))
   end)
 
   it('fails to dump a recursive (val) map in a special dict, _VAL reference', function()
-    execute('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": [[[], []]]}')
-    execute('call add(todump._VAL[0][1], todump._VAL)')
+    command('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": [[[], []]]}')
+    command('call add(todump._VAL[0][1], todump._VAL)')
     eq('Vim(call):E5005: Unable to dump msgpackdump() argument, index 0: container references itself in key [] at index 0 from special map, index 0',
        exc_exec('call msgpackdump([todump])'))
   end)
 
   it('fails to dump a recursive (val) special list in a special dict',
   function()
-    execute('let todump = {"_TYPE": v:msgpack_types.array, "_VAL": []}')
-    execute('call add(todump._VAL, [0, todump._VAL])')
+    command('let todump = {"_TYPE": v:msgpack_types.array, "_VAL": []}')
+    command('call add(todump._VAL, [0, todump._VAL])')
     eq('Vim(call):E5005: Unable to dump msgpackdump() argument, index 0: container references itself in index 0, index 1',
        exc_exec('call msgpackdump([todump])'))
   end)
@@ -689,7 +690,7 @@ describe('msgpackdump() function', function()
   end)
 
   it('fails to dump a partial', function()
-    execute('function T() dict\nendfunction')
+    command('function T() dict\nendfunction')
     eq('Vim(call):E686: Argument of msgpackdump() must be a List',
        exc_exec('call msgpackdump(function("T", [1, 2], {}))'))
   end)
diff --git a/test/functional/eval/reltime_spec.lua b/test/functional/eval/reltime_spec.lua
index 0b19d372ec..0181f09024 100644
--- a/test/functional/eval/reltime_spec.lua
+++ b/test/functional/eval/reltime_spec.lua
@@ -1,6 +1,6 @@
 local helpers = require('test.functional.helpers')(after_each)
 local clear, eq, ok = helpers.clear,  helpers.eq, helpers.ok
-local neq, execute, funcs  = helpers.neq, helpers.execute, helpers.funcs
+local neq, command, funcs  = helpers.neq, helpers.command, helpers.funcs
 local reltime, reltimestr, reltimefloat = funcs.reltime, funcs.reltimestr, funcs.reltimefloat
 
 describe('reltimestr(), reltimefloat()', function()
@@ -8,7 +8,7 @@ describe('reltimestr(), reltimefloat()', function()
 
   it('Checks', function()
     local now = reltime()
-    execute('sleep 10m')
+    command('sleep 10m')
     local later = reltime()
     local elapsed = reltime(now)
 
diff --git a/test/functional/eval/setpos_spec.lua b/test/functional/eval/setpos_spec.lua
index 2e27cd8ac0..6a8b3a8732 100644
--- a/test/functional/eval/setpos_spec.lua
+++ b/test/functional/eval/setpos_spec.lua
@@ -3,7 +3,7 @@ local setpos = helpers.funcs.setpos
 local getpos = helpers.funcs.getpos
 local insert = helpers.insert
 local clear = helpers.clear
-local execute = helpers.execute
+local command = helpers.command
 local eval = helpers.eval
 local eq = helpers.eq
 local exc_exec = helpers.exc_exec
@@ -16,7 +16,7 @@ describe('setpos() function', function()
     First line of text
     Second line of text
     Third line of text]])
-    execute('new')
+    command('new')
     insert([[
     Line of text 1
     Line of text 2
@@ -34,7 +34,8 @@ describe('setpos() function', function()
   it('can set lowercase marks in the current buffer', function()
     setpos("'d", {0, 2, 1, 0})
     eq(getpos("'d"), {0, 2, 1, 0})
-    execute('undo', 'call setpos("\'d", [2, 3, 1, 0])')
+    command('undo')
+    command('call setpos("\'d", [2, 3, 1, 0])')
     eq(getpos("'d"), {0, 3, 1, 0})
   end)
   it('can set lowercase marks in other buffers', function()
@@ -42,7 +43,7 @@ describe('setpos() function', function()
     eq(0, retval)
     setpos("'d", {1, 2, 1, 0})
     eq(getpos("'d"), {0, 0, 0, 0})
-    execute('wincmd w')
+    command('wincmd w')
     eq(eval('bufnr("%")'), 1)
     eq(getpos("'d"), {0, 2, 1, 0})
   end)
diff --git a/test/functional/eval/special_vars_spec.lua b/test/functional/eval/special_vars_spec.lua
index 4c5d63ce23..3d9358447e 100644
--- a/test/functional/eval/special_vars_spec.lua
+++ b/test/functional/eval/special_vars_spec.lua
@@ -1,6 +1,6 @@
 local helpers = require('test.functional.helpers')(after_each)
 local exc_exec = helpers.exc_exec
-local execute = helpers.execute
+local command = helpers.command
 local funcs = helpers.funcs
 local clear = helpers.clear
 local eval = helpers.eval
@@ -12,7 +12,7 @@ describe('Special values', function()
   before_each(clear)
 
   it('do not cause error when freed', function()
-    execute([[
+    command([[
       function Test()
         try
           return v:true
@@ -109,7 +109,7 @@ describe('Special values', function()
   it('does not work with +=/-=/.=', function()
     meths.set_var('true', true)
     meths.set_var('false', false)
-    execute('let null = v:null')
+    command('let null = v:null')
 
     eq('Vim(let):E734: Wrong variable type for +=', exc_exec('let true  += 1'))
     eq('Vim(let):E734: Wrong variable type for +=', exc_exec('let false += 1'))
diff --git a/test/functional/eval/system_spec.lua b/test/functional/eval/system_spec.lua
index ee75b593ff..0b7d3dce21 100644
--- a/test/functional/eval/system_spec.lua
+++ b/test/functional/eval/system_spec.lua
@@ -1,6 +1,6 @@
 local helpers = require('test.functional.helpers')(after_each)
-local eq, call, clear, eval, execute, feed, nvim =
-  helpers.eq, helpers.call, helpers.clear, helpers.eval, helpers.execute,
+local eq, call, clear, eval, feed_command, feed, nvim =
+  helpers.eq, helpers.call, helpers.clear, helpers.eval, helpers.feed_command,
   helpers.feed, helpers.nvim
 
 local Screen = require('test.functional.ui.screen')
@@ -43,10 +43,10 @@ describe('system()', function()
     it('parameter validation does NOT modify v:shell_error', function()
       -- 1. Call system() with invalid parameters.
       -- 2. Assert that v:shell_error was NOT set.
-      execute('call system({})')
+      feed_command('call system({})')
       eq('E475: Invalid argument: expected String or List', eval('v:errmsg'))
       eq(0, eval('v:shell_error'))
-      execute('call system([])')
+      feed_command('call system([])')
       eq('E474: Invalid argument', eval('v:errmsg'))
       eq(0, eval('v:shell_error'))
 
@@ -57,9 +57,9 @@ describe('system()', function()
 
       -- 1. Call system() with invalid parameters.
       -- 2. Assert that v:shell_error was NOT modified.
-      execute('call system({})')
+      feed_command('call system({})')
       eq(old_val, eval('v:shell_error'))
-      execute('call system([])')
+      feed_command('call system([])')
       eq(old_val, eval('v:shell_error'))
     end)
 
@@ -182,7 +182,7 @@ describe('system()', function()
     end)
     it('to backgrounded command does not crash', function()
       -- This is indeterminate, just exercise the codepath. May get E5677.
-      execute('call system("echo -n echoed &")')
+      feed_command('call system("echo -n echoed &")')
       local v_errnum = string.match(eval("v:errmsg"), "^E%d*:")
       if v_errnum then
         eq("E5677:", v_errnum)
@@ -197,7 +197,7 @@ describe('system()', function()
     end)
     it('to backgrounded command does not crash', function()
       -- This is indeterminate, just exercise the codepath. May get E5677.
-      execute('call system("cat - &")')
+      feed_command('call system("cat - &")')
       local v_errnum = string.match(eval("v:errmsg"), "^E%d*:")
       if v_errnum then
         eq("E5677:", v_errnum)
diff --git a/test/functional/eval/timer_spec.lua b/test/functional/eval/timer_spec.lua
index b3c4cd07eb..2dd9968a01 100644
--- a/test/functional/eval/timer_spec.lua
+++ b/test/functional/eval/timer_spec.lua
@@ -2,7 +2,7 @@ local helpers = require('test.functional.helpers')(after_each)
 local Screen = require('test.functional.ui.screen')
 local ok, feed, eq, eval = helpers.ok, helpers.feed, helpers.eq, helpers.eval
 local source, nvim_async, run = helpers.source, helpers.nvim_async, helpers.run
-local clear, execute, funcs = helpers.clear, helpers.execute, helpers.funcs
+local clear, command, funcs = helpers.clear, helpers.command, helpers.funcs
 local curbufmeths = helpers.curbufmeths
 
 describe('timers', function()
@@ -17,14 +17,14 @@ describe('timers', function()
   end)
 
   it('works one-shot', function()
-    execute("call timer_start(50, 'MyHandler')")
+    command("call timer_start(50, 'MyHandler')")
     eq(0,eval("g:val"))
     run(nil, nil, nil, 200)
     eq(1,eval("g:val"))
   end)
 
   it('works one-shot when repeat=0', function()
-    execute("call timer_start(50, 'MyHandler', {'repeat': 0})")
+    command("call timer_start(50, 'MyHandler', {'repeat': 0})")
     eq(0,eval("g:val"))
     run(nil, nil, nil, 200)
     eq(1,eval("g:val"))
@@ -32,14 +32,14 @@ describe('timers', function()
 
 
   it('works with repeat two', function()
-    execute("call timer_start(50, 'MyHandler', {'repeat': 2})")
+    command("call timer_start(50, 'MyHandler', {'repeat': 2})")
     eq(0,eval("g:val"))
     run(nil, nil, nil, 300)
     eq(2,eval("g:val"))
   end)
 
   it('are triggered during sleep', function()
-    execute("call timer_start(50, 'MyHandler', {'repeat': 2})")
+    command("call timer_start(50, 'MyHandler', {'repeat': 2})")
     nvim_async("command", "sleep 10")
     eq(0,eval("g:val"))
     run(nil, nil, nil, 300)
@@ -63,12 +63,12 @@ describe('timers', function()
   end)
 
   it('are paused when event processing is disabled', function()
-    execute("call timer_start(50, 'MyHandler', {'repeat': -1})")
+    command("call timer_start(50, 'MyHandler', {'repeat': -1})")
     run(nil, nil, nil, 100)
     local count = eval("g:val")
     -- shows two line error message and thus invokes the return prompt.
     -- if we start to allow event processing here, we need to change this test.
-    execute("throw 'fatal error'")
+    feed(':throw "fatal error"<CR>')
     run(nil, nil, nil, 300)
     feed("<cr>")
     local diff = eval("g:val") - count
@@ -76,7 +76,7 @@ describe('timers', function()
   end)
 
   it('are triggered in blocking getchar() call', function()
-    execute("call timer_start(50, 'MyHandler', {'repeat': -1})")
+    command("call timer_start(50, 'MyHandler', {'repeat': -1})")
     nvim_async("command", "let g:c = getchar()")
     run(nil, nil, nil, 300)
     feed("c")
@@ -157,7 +157,7 @@ describe('timers', function()
         endif
       endfunc
     ]])
-    execute("call timer_start(50, 'MyHandler', {'repeat': -1})")
+    command("call timer_start(50, 'MyHandler', {'repeat': -1})")
     eq(0,eval("g:val"))
     run(nil, nil, nil, 300)
     eq(3,eval("g:val"))
@@ -170,8 +170,8 @@ describe('timers', function()
         let g:val2 += 1
       endfunc
     ]])
-    execute("call timer_start(50,  'MyHandler', {'repeat': 3})")
-    execute("call timer_start(100, 'MyHandler2', {'repeat': 2})")
+    command("call timer_start(50,  'MyHandler', {'repeat': 3})")
+    command("call timer_start(100, 'MyHandler2', {'repeat': 2})")
     run(nil, nil, nil, 300)
     eq(3,eval("g:val"))
     eq(2,eval("g:val2"))
@@ -186,7 +186,7 @@ describe('timers', function()
         let g:val += 1
       endfunc
     ]])
-    execute("call timer_start(5, 'MyHandler', {'repeat': 1})")
+    command("call timer_start(5, 'MyHandler', {'repeat': 1})")
     run(nil, nil, nil, 300)
     eq(1,eval("g:val"))
   end)
@@ -201,7 +201,7 @@ describe('timers', function()
         echo "evil"
       endfunc
     ]])
-    execute("call timer_start(100,  'MyHandler', {'repeat': 1})")
+    command("call timer_start(100,  'MyHandler', {'repeat': 1})")
     feed(":good")
     screen:sleep(200)
     screen:expect([[