diff --git a/src/testdir/test_timers.vim b/src/testdir/test_timers.vim
index 4bde75f..d2f621c 100644
--- a/src/testdir/test_timers.vim
+++ b/src/testdir/test_timers.vim
@@ -44,11 +44,15 @@
   let slept = WaitFor('g:val == 3')
   call assert_equal(3, g:val)
   if has('reltime')
+    " Timer has an internal 1ms allowance in calculating due time, so it's
+    " possible for each timer to undershoot by 1ms resulting in only 49*3=147
+    " ms elapsed. Additionally we started the timer before we called
+    " WaitFor(), so the reported time could be a couple more ms below 147.
     if has('mac')
-      " Mac on Travis can be slow.
-      call assert_inrange(149, 400, slept)
+      " Mac in CI can be slow.
+      call assert_inrange(145, 400, slept)
     else
-      call assert_inrange(149, 250, slept)
+      call assert_inrange(145, 250, slept)
     endif
   else
     call assert_inrange(80, 200, slept)
@@ -143,13 +147,13 @@
   # Another timer will fire in half a second and close it early after stopping
   # all timers.
   var pop = popup_create('Popup', {time: 10000})
-  var tmr = timer_start(500, (_) => {
+  var tmr = timer_start(100, (_) => {
     timer_stopall()
     popup_clear()
   })
-  sleep 1
+  sleep 100m
+  g:WaitForAssert(() => assert_equal([], popup_list()), 1000)
   assert_equal([], timer_info(tmr))
-  assert_equal([], popup_list())
 enddef
 
 func Test_timer_paused()