patch 7.4.2014
Problem:    Using "noinsert" in 'completeopt' does not insert match.
Solution:   Set compl_enter_selects. (Shougo, closes #875)
diff --git a/src/testdir/test_popup.vim b/src/testdir/test_popup.vim
index cefaee2..ea489f9 100644
--- a/src/testdir/test_popup.vim
+++ b/src/testdir/test_popup.vim
@@ -49,8 +49,20 @@
   call feedkeys("i\<F5>soun\<CR>\<CR>\<ESC>.", 'tx')
   call assert_equal('soundfold', getline(1))
   call assert_equal('soundfold', getline(2))
-
   bwipe!
+
+  new
+  inoremap <F5>  <C-R>=Test()<CR>
+  call feedkeys("i\<F5>\<CR>\<ESC>", 'tx')
+  call assert_equal('source', getline(1))
+  bwipe!
+
   set completeopt-=noinsert
   iunmap <F5>
 endfunc
+
+
+function! Test() abort
+  call complete(1, ['source', 'soundfold'])
+  return ''
+endfunction