vim-patch:8.0.1539: no test for the popup menu positioning

Problem:    No test for the popup menu positioning.
Solution:   Add a screendump test for the popup menu.
6bb2cdfe60

runtime/doc/eval.txt

@@ -6657,7 +6657,7 @@ remote_expr({server}, {string} [, {idvar} [, {timeout}]])
 		between (not at the end), like with join(expr, "\n").
 		If {idvar} is present and not empty, it is taken as the name
 		of a variable and a {serverid} for later use with
-		remote_read() is stored there.
+		|remote_read()| is stored there.
 		If {timeout} is given the read times out after this many
 		seconds.  Otherwise a timeout of 600 seconds is used.
 		See also |clientserver| |RemoteReply|.

src/nvim/testdir/test_popup.vim

@@ -1,6 +1,7 @@
 " Test for completion menu
 
 source shared.vim
+source screendump.vim
 
 let g:months = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December']
 let g:setting = ''
@@ -735,6 +736,38 @@ func Test_popup_and_preview_autocommand()
   bw!
 endfunc
 
+func Test_popup_position()
+  if !CanRunVimInTerminal()
+    return
+  endif
+  call writefile([
+	\ '123456789_123456789_123456789_a',
+	\ '123456789_123456789_123456789_b',
+	\ '            123',
+	\ ], 'Xtest')
+  let buf = RunVimInTerminal('Xtest', {})
+  call term_sendkeys(buf, ":vsplit\<CR>")
+
+  " default pumwidth in left window: overlap in right window
+  call term_sendkeys(buf, "GA\<C-N>")
+  call VerifyScreenDump(buf, 'Test_popup_position_01', {'rows': 8})
+  call term_sendkeys(buf, "\<Esc>u")
+
+  " default pumwidth: fill until right of window
+  call term_sendkeys(buf, "\<C-W>l")
+  call term_sendkeys(buf, "GA\<C-N>")
+  call VerifyScreenDump(buf, 'Test_popup_position_02', {'rows': 8})
+
+  " larger pumwidth: used as minimum width
+  call term_sendkeys(buf, "\<Esc>u")
+  call term_sendkeys(buf, ":set pumwidth=30\<CR>")
+  call term_sendkeys(buf, "GA\<C-N>")
+  call VerifyScreenDump(buf, 'Test_popup_position_03', {'rows': 8})
+
+  call term_sendkeys(buf, "\<Esc>u")
+  call StopVimInTerminal(buf)
+  call delete('Xtest')
+endfunc
 
 func Test_popup_complete_backwards()
   new

src/nvim/testdir/test_syntax.vim

@@ -1,6 +1,7 @@
 " Test for syntax and syntax iskeyword option
 
 source view_util.vim
+source screendump.vim
 
 func GetSyntaxItem(pat)
   let c = ''
@@ -526,7 +527,7 @@ func Test_syntax_c()
   let $COLORFGBG = '15;0'
 
   let buf = RunVimInTerminal('Xtest.c', {})
-  call VerifyScreenDump(buf, 'Test_syntax_c_01')
+  call VerifyScreenDump(buf, 'Test_syntax_c_01', {})
   call StopVimInTerminal(buf)
 
   let $COLORFGBG = ''