vim-patch:8.0.1776: in tests, when WaitFor() fails it doesn't say why

Problem:    In tests, when WaitFor() fails it doesn't say why.
Solution:   Turn a few more WaitFor() into WaitForAssert().
0e9d1ae321

src/nvim/testdir/test_popup.vim

@@ -681,18 +681,15 @@ func Test_popup_and_window_resize()
   call term_sendkeys(buf, "\<c-v>")
   call term_wait(buf, 100)
   " popup first entry "!" must be at the top
-  call WaitFor({-> term_getline(buf, 1) =~ "^!"})
-  call assert_match('^!\s*$', term_getline(buf, 1))
+  call WaitForAssert({-> assert_match('^!\s*$', term_getline(buf, 1))})
   exe 'resize +' . (h - 1)
   call term_wait(buf, 100)
   redraw!
   " popup shifted down, first line is now empty
-  call WaitFor({-> term_getline(buf, 1) == ""})
-  call assert_equal('', term_getline(buf, 1))
+  call WaitForAssert({-> assert_equal('', term_getline(buf, 1))})
   sleep 100m
   " popup is below cursor line and shows first match "!"
-  call WaitFor({-> term_getline(buf, term_getcursor(buf)[0] + 1) =~ "^!"})
-  call assert_match('^!\s*$', term_getline(buf, term_getcursor(buf)[0] + 1))
+  call WaitForAssert({-> assert_match('^!\s*$', term_getline(buf, term_getcursor(buf)[0] + 1))})
   " cursor line also shows !
   call assert_match('^!\s*$', term_getline(buf, term_getcursor(buf)[0]))
   bwipe!

src/nvim/testdir/test_quotestar.vim

@@ -54,34 +54,33 @@ func Do_test_quotestar_for_x11()
   " Make sure a previous server has exited
   try
     call remote_send(name, ":qa!\<CR>")
-    call WaitFor('serverlist() !~ "' . name . '"')
   catch /E241:/
   endtry
-  call assert_notmatch(name, serverlist())
+  call WaitForAssert({-> assert_notmatch(name, serverlist())})
 
   let cmd .= ' --servername ' . name
   let job = job_start(cmd, {'stoponexit': 'kill', 'out_io': 'null'})
-  call WaitFor({-> job_status(job) == "run"})
+  call WaitForAssert({-> assert_equal("run", job_status(job))})
 
   " Takes a short while for the server to be active.
-  call WaitFor('serverlist() =~ "' . name . '"')
+  call WaitForAssert({-> assert_match(name, serverlist())})
 
   " Wait for the server to be up and answering requests.  One second is not
   " always sufficient.
-  call WaitFor('remote_expr("' . name . '", "v:version", "", 2) != ""')
+  call WaitForAssert({-> assert_notequal('', remote_expr(name, "v:version", "", 2))})
 
   " Clear the *-register of this vim instance and wait for it to be picked up
   " by the server.
   let @* = 'no'
   call remote_foreground(name)
-  call WaitFor('remote_expr("' . name . '", "@*", "", 1) == "no"')
+  call WaitForAssert({-> assert_equal("no", remote_expr(name, "@*", "", 1))})
 
   " Set the * register on the server.
   call remote_send(name, ":let @* = 'yes'\<CR>")
-  call WaitFor('remote_expr("' . name . '", "@*", "", 1) == "yes"')
+  call WaitForAssert({-> assert_equal("yes", remote_expr(name, "@*", "", 1))})
 
   " Check that the *-register of this vim instance is changed as expected.
-  call WaitFor('@* == "yes"')
+  call WaitForAssert({-> assert_equal("yes", @*)})
 
   " Handle the large selection over 262040 byte.
   let length = 262044
@@ -109,18 +108,17 @@ func Do_test_quotestar_for_x11()
       call remote_send(name, ":gui -f\<CR>")
     endif
     " Wait for the server in the GUI to be up and answering requests.
-    call WaitFor('remote_expr("' . name . '", "has(\"gui_running\")", "", 1) =~ "1"')
+    call WaitForAssert({-> assert_match("1", remote_expr(name, "has('gui_running')", "", 1))})
 
     call remote_send(name, ":let @* = 'maybe'\<CR>")
-    call WaitFor('remote_expr("' . name . '", "@*", "", 1) == "maybe"')
-    call assert_equal('maybe', remote_expr(name, "@*", "", 2))
+    call WaitForAssert({-> assert_equal("maybe", remote_expr(name, "@*", "", 2))})
 
     call assert_equal('maybe', @*)
   endif
 
   call remote_send(name, ":qa!\<CR>")
   try
-    call WaitFor({-> job_status(job) == "dead"})
+    call WaitForAssert({-> assert_equal("dead", job_status(job))})
   finally
     if job_status(job) != 'dead'
       call assert_report('Server did not exit')

src/nvim/testdir/test_timers.vim

@@ -141,7 +141,7 @@ endfunc
 func Test_delete_myself()
   let g:called = 0
   let t = timer_start(10, 'StopMyself', {'repeat': -1})
-  call WaitFor('g:called == 2')
+  call WaitForAssert({-> assert_equal(2, g:called)})
   call assert_equal(2, g:called)
   call assert_equal([], timer_info(t))
 endfunc
@@ -208,7 +208,7 @@ func Test_timer_errors()
   let g:call_count = 0
   let timer = timer_start(10, 'FuncWithError', {'repeat': -1})
   " Timer will be stopped after failing 3 out of 3 times.
-  call WaitFor('g:call_count == 3')
+  call WaitForAssert({-> assert_equal(3, g:call_count)})
   sleep 50m
   call assert_equal(3, g:call_count)
 endfunc
@@ -226,7 +226,7 @@ func Test_timer_catch_error()
   let g:call_count = 0
   let timer = timer_start(10, 'FuncWithCaughtError', {'repeat': 4})
   " Timer will not be stopped.
-  call WaitFor('g:call_count == 4')
+  call WaitForAssert({-> assert_equal(4, g:call_count)})
   sleep 50m
   call assert_equal(4, g:call_count)
 endfunc