Async.Promise: Extend another timeout in the test

Author: ujihisa

test/Async/Promise.vimspec

@@ -1,6 +1,10 @@
 function! s:wait_has_key(obj, name) abort
+  return s:wait_has_key_with_timeout(a:obj, a:name, 5)
+endfunction
+
+function! s:wait_has_key_with_timeout(obj, name, timeout_sec) abort
   let i = 0
-  while i < 500
+  while i < a:timeout_sec * 100
     sleep 10m
     if has_key(a:obj, a:name)
       return
@@ -621,7 +625,7 @@ Describe Async.Promise
         Assert Equals(p._state, FULFILLED)
         let l = l:
         call p.then({x -> extend(l, {'result' : x})})
-        call s:wait_has_key(l, 'result')
+        call s:wait_has_key_with_timeout(l, 'result', 50) " 10 times longer than default
         Assert Equals(result, 42)
         unlet result
       endfor