diff --git a/contrib/testRender.py b/contrib/testRender.py
new file mode 100644
index 0000000..7646dad
--- /dev/null
+++ b/contrib/testRender.py
@@ -0,0 +1,144 @@
+#!/usr/bin/python
+
+import os, shutil, tempfile, time, sys, math, re
+from subprocess import Popen, PIPE, STDOUT, CalledProcessError
+from optparse import OptionParser
+
+def check_call(*args, **kwargs):
+    quiet = False
+    if "quiet" in kwargs.keys():
+        quiet = kwargs["quiet"]
+        del kwargs["quiet"]
+    if quiet:
+        kwargs['stdout'] = PIPE
+        kwargs['stderr'] = STDOUT
+    p = Popen(*args, **kwargs)
+    output = ""
+    if quiet:
+        while p.poll() == None:
+            output += p.communicate()[0]
+    returncode = p.wait()
+    if returncode:
+        if quiet:
+            print output
+        raise CalledProcessError(returncode, args)
+    return returncode
+
+def check_output(*args, **kwargs):
+    kwargs['stdout'] = PIPE
+    # will hang for HUGE output... you were warned
+    p = Popen(*args, **kwargs)
+    returncode = p.wait()
+    if returncode:
+        raise CalledProcessError(returncode, args)
+    return p.communicate()[0]
+
+def clean_render(overviewerargs, quiet):
+    tempdir = tempfile.mkdtemp('mc-overviewer-test')
+    try:
+        # check_call raises CalledProcessError when overviewer.py exits badly
+        check_call(['python', 'setup.py', 'clean', 'build'], quiet=quiet)
+        check_call(['./overviewer.py', '-d'] + overviewerargs, quiet=quiet)
+        starttime = time.time()
+        check_call(['./overviewer.py',] + overviewerargs + [tempdir,], quiet=quiet)
+        endtime = time.time()
+        
+        return endtime - starttime
+    finally:
+        shutil.rmtree(tempdir, True)
+
+def get_stats(timelist):
+    stats = {}
+    
+    stats['count'] = len(timelist)
+    stats['minimum'] = min(timelist)
+    stats['maximum'] = max(timelist)
+    stats['average'] = sum(timelist) / float(len(timelist))
+    
+    meandiff = map(lambda x: (x - stats['average'])**2, timelist)
+    stats['standard deviation'] = math.sqrt(sum(meandiff) / float(len(meandiff)))
+    
+    return stats
+
+commitre = re.compile('^commit ([a-z0-9]{40})$', re.MULTILINE)
+branchre = re.compile('^\\* (.+)$', re.MULTILINE)
+def get_current_commit():
+    gittext = check_output(['git', 'branch'])
+    match = branchre.search(gittext)
+    if match and not ("no branch" in match.group(1)):
+        return match.group(1)
+    gittext = check_output(['git', 'show', 'HEAD'])
+    match = commitre.match(gittext)
+    if match == None:
+        return None
+    return match.group(1)
+
+def get_commits(gitrange):
+    gittext = check_output(['git', 'log', '--raw', '--reverse', gitrange])
+    for match in commitre.finditer(gittext):
+        yield match.group(1)
+
+def set_commit(commit):
+    check_call(['git', 'checkout', commit], quiet=True)
+
+parser = OptionParser(usage="usage: %prog [options] -- [overviewer options/world]")
+parser.add_option("-n", "--number", metavar="N",
+                  action="store", type="int", dest="number", default=3,
+                  help="number of renders per commit [default: 3]")
+parser.add_option("-c", "--commits", metavar="RANGE",
+                  action="append", type="string", dest="commits", default=[],
+                  help="the commit (or range of commits) to test [default: current]")
+parser.add_option("-v", "--verbose",
+                  action="store_false", dest="quiet", default=True,
+                  help="don't suppress overviewer output")
+parser.add_option("-k", "--keep-going",
+                  action="store_false", dest="fatal_errors", default=True,
+                  help="don't stop testing when Overviewer croaks")
+parser.add_option("-l", "--log", dest="log", default="", metavar="FILE",
+                  help="log all test results to a file")
+
+(options, args) = parser.parse_args()
+
+if len(args) == 0:
+    parser.print_help()
+    sys.exit(0)
+
+commits = []
+for commit in options.commits:
+    if '..' in commit:
+        commits = get_commits(commit)
+    else:
+        commits.append(commit)
+if not commits:
+    commits = [get_current_commit(),]
+
+log = None
+if options.log != "":
+    log = open(options.log, "w")
+
+reset_commit = get_current_commit()
+try:
+    for commit in commits:
+        print "testing commit", commit
+        set_commit(commit)
+        timelist = []
+        print " -- ",
+        try:
+            for i in range(options.number):
+                sys.stdout.write(str(i+1)+" ")
+                sys.stdout.flush()
+                timelist.append(clean_render(args, options.quiet))
+            print "... done"
+            stats = get_stats(timelist)
+            print stats
+            log.write("%s %s\n" % (commit, repr(stats)))
+        except CalledProcessError, e:
+            if options.fatal_errors:
+                print
+                print "Overviewer croaked, exiting..."
+                print "(to avoid this, use --keep-going)"
+                sys.exit(1)
+finally:
+    set_commit(reset_commit)
+    if log:
+        log.close()