diff --git a/test_progress.py b/test_progress.py
index ecb6125..ae7bb19 100755
--- a/test_progress.py
+++ b/test_progress.py
@@ -2,38 +2,45 @@
 
 from __future__ import print_function
 
-from random import randint
-from time import sleep
+import random
+import time
 
 from progress.bar import (Bar, ChargingBar, FillingSquaresBar,
                           FillingCirclesBar, IncrementalBar, ShadyBar)
 from progress.spinner import Spinner, PieSpinner, MoonSpinner, LineSpinner
 from progress.counter import Counter, Countdown, Stack, Pie
 
+
+def sleep():
+    t = 0.01
+    t += t * random.uniform(-0.1, 0.1)  # Add some variance
+    time.sleep(t)
+
+
 for bar_cls in (Bar, ChargingBar, FillingSquaresBar, FillingCirclesBar):
     suffix = '%(index)d/%(max)d [%(elapsed)d / %(eta)d]'
     bar = bar_cls(bar_cls.__name__, suffix=suffix)
-    for i in bar.iter(range(100)):
-        sleep(0.04)
+    for i in bar.iter(range(200)):
+        sleep()
 
 for bar_cls in (IncrementalBar, ShadyBar):
     suffix = '%(percent)d%% [%(elapsed_td)s / %(eta_td)s]'
     bar = bar_cls(bar_cls.__name__, suffix=suffix)
     for i in bar.iter(range(200)):
-        sleep(0.02)
+        sleep()
 
 for spin in (Spinner, PieSpinner, MoonSpinner, LineSpinner):
-    for i in spin(spin.__name__ + ' ').iter(range(30)):
-        sleep(0.1)
+    for i in spin(spin.__name__ + ' ').iter(range(100)):
+        sleep()
     print()
 
 for singleton in (Counter, Countdown, Stack, Pie):
     for i in singleton(singleton.__name__ + ' ').iter(range(100)):
-        sleep(0.03)
+        sleep()
     print()
 
 bar = IncrementalBar('Random', suffix='%(index)d')
 for i in range(100):
-    bar.goto(randint(0, 100))
-    sleep(0.1)
+    bar.goto(random.randint(0, 100))
+    sleep()
 bar.finish()