diff --git a/src/testdir/test_cursor_func.vim b/src/testdir/test_cursor_func.vim
index 66d5d03..dc65fdc 100644
--- a/src/testdir/test_cursor_func.vim
+++ b/src/testdir/test_cursor_func.vim
@@ -83,7 +83,7 @@
   call assert_equal({'row': winrow,
 	\ 'col': wincol + 0,
 	\ 'curscol': wincol + 7,
-	\ 'endcol': wincol + 7}, screenpos(winid, 1, 1))
+	\ 'endcol': wincol + 7}, winid->screenpos(1, 1))
   call assert_equal({'row': winrow,
 	\ 'col': wincol + 13,
 	\ 'curscol': wincol + 13,
diff --git a/src/testdir/test_execute_func.vim b/src/testdir/test_execute_func.vim
index f3d7e37..f81a86b 100644
--- a/src/testdir/test_execute_func.vim
+++ b/src/testdir/test_execute_func.vim
@@ -91,7 +91,7 @@
   if has('textprop')
     let popupwin = popup_create('the popup win', {'line': 2, 'col': 3})
     redraw
-    let line = win_execute(popupwin, 'echo getline(1)')
+    let line = 'echo getline(1)'->win_execute(popupwin)
     call assert_match('the popup win', line)
 
     call popup_close(popupwin)
diff --git a/src/testdir/test_functions.vim b/src/testdir/test_functions.vim
index 4c6d2a8..2e051bb 100644
--- a/src/testdir/test_functions.vim
+++ b/src/testdir/test_functions.vim
@@ -266,7 +266,7 @@
 func s:normalize_fname(fname)
   let ret = substitute(a:fname, '\', '/', 'g')
   let ret = substitute(ret, '//', '/', 'g')
-  return tolower(ret)
+  return ret->tolower()
 endfunc
 
 func Test_resolve_win32()
@@ -505,7 +505,7 @@
           \ toupper(' !"#$%&''()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~'))
 
   " Test with a few lowercase diacritics.
-  call assert_equal("AÀÁÂÃÄÅĀĂĄǍǞǠẢ", toupper("aàáâãäåāăąǎǟǡả"))
+  call assert_equal("AÀÁÂÃÄÅĀĂĄǍǞǠẢ", "aàáâãäåāăąǎǟǡả"->toupper())
   call assert_equal("BḂḆ", toupper("bḃḇ"))
   call assert_equal("CÇĆĈĊČ", toupper("cçćĉċč"))
   call assert_equal("DĎĐḊḎḐ", toupper("dďđḋḏḑ"))
@@ -568,6 +568,11 @@
   call toupper("123\xC0\x80\xC0")
 endfunc
 
+func Test_tr()
+  call assert_equal('foo', tr('bar', 'bar', 'foo'))
+  call assert_equal('zxy', 'cab'->tr('abc', 'xyz'))
+endfunc
+
 " Tests for the mode() function
 let current_modes = ''
 func Save_mode()
@@ -1203,7 +1208,7 @@
 
 func Test_trim()
   call assert_equal("Testing", trim("  \t\r\r\x0BTesting  \t\n\r\n\t\x0B\x0B"))
-  call assert_equal("Testing", trim("  \t  \r\r\n\n\x0BTesting  \t\n\r\n\t\x0B\x0B"))
+  call assert_equal("Testing", "  \t  \r\r\n\n\x0BTesting  \t\n\r\n\t\x0B\x0B"->trim())
   call assert_equal("RESERVE", trim("xyz \twwRESERVEzyww \t\t", " wxyz\t"))
   call assert_equal("wRE    \tSERVEzyww", trim("wRE    \tSERVEzyww"))
   call assert_equal("abcd\t     xxxx   tail", trim(" \tabcd\t     xxxx   tail"))
@@ -1617,7 +1622,7 @@
   call assert_equal([''], getbufline(buf, 1, '$'))
 
   let curbuf = bufnr('')
-  call writefile(['some', 'text'], 'XotherName')
+  eval ['some', 'text']->writefile('XotherName')
   let buf = 'XotherName'->bufadd()
   call assert_notequal(0, buf)
   eval 'XotherName'->bufexists()->assert_equal(1)
diff --git a/src/testdir/test_listchars.vim b/src/testdir/test_listchars.vim
index a304c53..987ed66 100644
--- a/src/testdir/test_listchars.vim
+++ b/src/testdir/test_listchars.vim
@@ -25,7 +25,7 @@
   redraw!
   for i in range(1, 5)
     call cursor(i, 1)
-    call assert_equal([expected[i - 1]], ScreenLines(i, virtcol('$')))
+    call assert_equal([expected[i - 1]], ScreenLines(i, '$'->virtcol()))
   endfor
 
   set listchars-=trail:<
diff --git a/src/testdir/test_timers.vim b/src/testdir/test_timers.vim
index 261be27..a6a36f7 100644
--- a/src/testdir/test_timers.vim
+++ b/src/testdir/test_timers.vim
@@ -71,7 +71,7 @@
 
 func Test_timer_info()
   let id = timer_start(1000, 'MyHandler')
-  let info = timer_info(id)
+  let info = id->timer_info()
   call assert_equal(id, info[0]['id'])
   call assert_equal(1000, info[0]['time'])
   call assert_true(info[0]['remaining'] > 500)
@@ -109,7 +109,7 @@
   let info = timer_info(id)
   call assert_equal(0, info[0]['paused'])
 
-  call timer_pause(id, 1)
+  eval id->timer_pause(1)
   let info = timer_info(id)
   call assert_equal(1, info[0]['paused'])
   sleep 100m
@@ -149,7 +149,7 @@
 endfunc
 
 func StopTimer1(timer)
-  let g:timer2 = timer_start(10, 'StopTimer2')
+  let g:timer2 = 10->timer_start('StopTimer2')
   " avoid maxfuncdepth error
   call timer_pause(g:timer1, 1)
   sleep 20m
@@ -262,7 +262,7 @@
   let intr = timer_start(100, 'Interrupt')
   let c = getchar()
   call assert_equal(char2nr('a'), c)
-  call timer_stop(intr)
+  eval intr->timer_stop()
 endfunc
 
 func Test_timer_getchar_zero()
diff --git a/src/testdir/test_undo.vim b/src/testdir/test_undo.vim
index 5154b20..c424273 100644
--- a/src/testdir/test_undo.vim
+++ b/src/testdir/test_undo.vim
@@ -456,7 +456,7 @@
   call delete('Xundodir', 'd')
 
   " Test undofile() with 'undodir' set to a non-existing directory.
-  call assert_equal('', undofile('Xundofoo'))
+  call assert_equal('', 'Xundofoo'->undofile())
 
   if isdirectory('/tmp')
     set undodir=/tmp
diff --git a/src/testdir/test_window_cmd.vim b/src/testdir/test_window_cmd.vim
index f2a9f17..9bdae2c 100644
--- a/src/testdir/test_window_cmd.vim
+++ b/src/testdir/test_window_cmd.vim
@@ -72,7 +72,7 @@
 func Test_window_quit()
   e Xa
   split Xb
-  call assert_equal(2, winnr('$'))
+  call assert_equal(2, '$'->winnr())
   call assert_equal('Xb', bufname(winbufnr(1)))
   call assert_equal('Xa', bufname(winbufnr(2)))
 
@@ -88,7 +88,7 @@
   3wincmd s
   call assert_equal(2, winnr('$'))
   call assert_equal(3, winheight(0))
-  call assert_equal(winwidth(1), winwidth(2))
+  call assert_equal(winwidth(1), 2->winwidth())
 
   call assert_fails('botright topleft wincmd s', 'E442:')
   bw
@@ -300,7 +300,7 @@
 
   wincmd +
   call assert_equal(wh1, winheight(1))
-  call assert_equal(wh2, winheight(2))
+  call assert_equal(wh2, 2->winheight())
 
   2wincmd _
   call assert_equal(2, winheight(1))
@@ -845,4 +845,16 @@
   only | tabonly
 endfunc
 
+func Test_winrestview()
+  split runtest.vim
+  normal 50%
+  let view = winsaveview()
+  close
+  split runtest.vim
+  eval view->winrestview()
+  call assert_equal(view, winsaveview())
+
+  bwipe!
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab
diff --git a/src/testdir/test_window_id.vim b/src/testdir/test_window_id.vim
index d10d831..8bf4ede 100644
--- a/src/testdir/test_window_id.vim
+++ b/src/testdir/test_window_id.vim
@@ -67,7 +67,7 @@
 
   call win_gotoid(id2)
   call assert_equal("two", expand("%"))
-  call win_gotoid(id4)
+  eval id4->win_gotoid()
   call assert_equal("four", expand("%"))
   call win_gotoid(id1)
   call assert_equal("one", expand("%"))
@@ -75,17 +75,17 @@
   call assert_equal("five", expand("%"))
 
   call assert_equal(0, win_id2win(9999))
-  call assert_equal(nr5, win_id2win(id5))
+  call assert_equal(nr5, id5->win_id2win())
   call assert_equal(0, win_id2win(id1))
   tabnext
   call assert_equal(nr1, win_id2win(id1))
 
   call assert_equal([0, 0], win_id2tabwin(9999))
-  call assert_equal([1, nr2], win_id2tabwin(id2))
+  call assert_equal([1, nr2], id2->win_id2tabwin())
   call assert_equal([2, nr4], win_id2tabwin(id4))
 
   call assert_equal([], win_findbuf(9999))
-  call assert_equal([id2], win_findbuf(bufnr2))
+  call assert_equal([id2], bufnr2->win_findbuf())
   call win_gotoid(id5)
   split
   call assert_equal(sort([id5, win_getid()]), sort(win_findbuf(bufnr5)))
@@ -98,7 +98,7 @@
   tabfirst
   copen
   only
-  call assert_equal(win_getid(1), win_getid(1, 1))
+  call assert_equal(win_getid(1), 1->win_getid( 1))
   tabclose!
 endfunc
 
@@ -120,4 +120,11 @@
   call assert_equal(['col', [['leaf', w3], ['row', [['leaf', w4], ['leaf', w2]]], ['leaf', w1]]], winlayout())
 
   only!
+
+  let w1 = win_getid()
+  call assert_equal(['leaf', w1], winlayout(1))
+  tabnew
+  let w2 = win_getid()
+  call assert_equal(['leaf', w2], 2->winlayout())
+  tabclose
 endfunc