diff --git a/Lib/test/test_mhlib.py b/Lib/test/test_mhlib.py
new file mode 100644
index 00000000000..a7879623f1e
--- /dev/null
+++ b/Lib/test/test_mhlib.py
@@ -0,0 +1,328 @@
+"""
+   Tests for the mhlib module
+   Nick Mathewson
+"""
+
+### BUG: This suite doesn't currently test the mime functionality of
+###      mhlib.  It should.
+
+import unittest
+from test_support import run_unittest, TESTFN
+import os, StringIO
+
+import mhlib
+
+_mhroot = TESTFN+"_MH"
+_mhpath = os.path.join(_mhroot, "MH")
+_mhprofile = os.path.join(_mhroot, ".mh_profile")
+
+def normF(f):
+    return os.path.join(*f.split('/'))
+
+def writeFile(fname, contents):
+    dir = os.path.split(fname)[0]
+    if dir and not os.path.exists(dir):
+        mkdirs(dir)
+    f = open(fname, 'w')
+    f.write(contents)
+    f.close()
+
+def readFile(fname):
+    f = open(fname)
+    r = f.read()
+    f.close()
+    return r
+
+def writeProfile(dict):
+    contents = [ "%s: %s\n" % (k, v) for k, v in dict.iteritems() ]
+    writeFile(_mhprofile, "".join(contents))
+
+def writeContext(folder):
+    folder = normF(folder)
+    writeFile(os.path.join(_mhpath, "context"), 
+              "Current-Folder: %s\n" % folder)
+
+def writeCurMessage(folder, cur):
+    folder = normF(folder)
+    writeFile(os.path.join(_mhpath, folder, ".mh_sequences"),
+              "cur: %s\n"%cur)
+
+def writeMessage(folder, n, headers, body):
+    folder = normF(folder)
+    headers = "".join([ "%s: %s\n" % (k, v) for k, v in headers.iteritems() ])
+    contents = "%s\n%s\n" % (headers,body)
+    mkdirs(os.path.join(_mhpath, folder))
+    writeFile(os.path.join(_mhpath, folder, str(n)), contents)
+
+def getMH():
+    return mhlib.MH(os.path.abspath(_mhpath), _mhprofile)
+
+def sortLines(s):
+    lines = s.split("\n")
+    lines = [ line.strip() for line in lines if len(line) >= 2 ]
+    lines.sort()
+    return lines
+
+# These next 2 functions are copied from test_glob.py.
+def mkdirs(fname):
+    if os.path.exists(fname) or fname == '':
+        return
+    base, file = os.path.split(fname)
+    mkdirs(base)
+    os.mkdir(fname)
+
+def deltree(fname):
+    if not os.path.exists(fname):
+        return
+    for f in os.listdir(fname):
+        fullname = os.path.join(fname, f)
+        if os.path.isdir(fullname):
+            deltree(fullname)
+        else:
+            try:
+                os.unlink(fullname)
+            except:
+                pass
+    try:
+        os.rmdir(fname)
+    except:
+        pass
+
+class MhlibTests(unittest.TestCase):
+    def setUp(self):
+        deltree(_mhroot)
+        mkdirs(_mhpath)
+        writeProfile({'Path' : os.path.abspath(_mhpath), 
+                      'Editor': 'emacs',
+                      'ignored-attribute': 'camping holiday'})
+        # Note: These headers aren't really conformant to RFC822, but
+        #  mhlib shouldn't care about that.
+
+        # An inbox with a couple of messages.
+        writeMessage('inbox', 1, 
+                     {'From': 'Mrs. Premise',
+                      'To': 'Mrs. Conclusion',
+                      'Date': '18 July 2001'}, "Hullo, Mrs. Conclusion!\n")
+        writeMessage('inbox', 2, 
+                     {'From': 'Mrs. Conclusion',
+                      'To': 'Mrs. Premise',
+                      'Date': '29 July 2001'}, "Hullo, Mrs. Premise!\n")
+        
+        # A folder with many messages
+        for i in range(5, 101)+range(101, 201, 2):
+            writeMessage('wide', i, 
+                         {'From': 'nowhere', 'Subject': 'message #%s' % i},
+                         "This is message number %s\n" % i)
+        
+        # A deeply nested folder
+        def deep(folder, n):
+            writeMessage(folder, n, 
+                         {'Subject': 'Message %s/%s' % (folder, n) },
+                         "This is message number %s in %s\n" % (n, folder) )
+        deep('deep/f1', 1)
+        deep('deep/f1', 2)
+        deep('deep/f1', 3)
+        deep('deep/f2', 4)
+        deep('deep/f2', 6)
+        deep('deep', 3)
+        deep('deep/f2/f3', 1)
+        deep('deep/f2/f3', 2)
+        
+    def tearDown(self):
+        deltree(_mhroot)
+    
+    def test_basic(self):
+        writeContext('inbox')
+        writeCurMessage('inbox', 2)
+        mh = getMH()
+
+        eq = self.assertEquals
+        eq(mh.getprofile('Editor'), 'emacs')
+        eq(mh.getprofile('not-set'), None)
+        eq(mh.getpath(), os.path.abspath(_mhpath))
+        eq(mh.getcontext(), 'inbox')
+
+        mh.setcontext('wide')
+        eq(mh.getcontext(), 'wide')
+        eq(readFile(os.path.join(_mhpath, 'context')),
+           "Current-Folder: wide\n")
+
+        mh.setcontext('inbox')
+
+        inbox = mh.openfolder('inbox')
+        eq(inbox.getfullname(), 
+           os.path.join(os.path.abspath(_mhpath), 'inbox'))
+        eq(inbox.getsequencesfilename(), 
+           os.path.join(os.path.abspath(_mhpath), 'inbox', '.mh_sequences'))
+        eq(inbox.getmessagefilename(1), 
+           os.path.join(os.path.abspath(_mhpath), 'inbox', '1'))
+        
+    def test_listfolders(self):
+        mh = getMH()
+        eq = self.assertEquals
+
+        folders = mh.listfolders()
+        folders.sort()
+        eq(folders, ['deep', 'inbox', 'wide'])
+        
+        folders = mh.listallfolders()
+        folders.sort()
+        eq(folders, map(normF, ['deep', 'deep/f1', 'deep/f2', 'deep/f2/f3',
+                                'inbox', 'wide']))
+
+        folders = mh.listsubfolders('deep')
+        folders.sort()
+        eq(folders, map(normF, ['deep/f1', 'deep/f2']))
+        
+        folders = mh.listallsubfolders('deep')
+        folders.sort()
+        eq(folders, map(normF, ['deep/f1', 'deep/f2', 'deep/f2/f3']))
+        eq(mh.listsubfolders(normF('deep/f2')), [normF('deep/f2/f3')])
+
+        eq(mh.listsubfolders('inbox'), [])
+        eq(mh.listallsubfolders('inbox'), [])
+
+    def test_sequence(self):
+        mh = getMH()
+        eq = self.assertEquals
+        writeCurMessage('wide', 55)
+        
+        f = mh.openfolder('wide')
+        all = f.listmessages()
+        eq(all, range(5, 101)+range(101, 201, 2))
+        eq(f.getcurrent(), 55)
+        f.setcurrent(99)
+        eq(readFile(os.path.join(_mhpath, 'wide', '.mh_sequences')), 
+           'cur: 99\n')
+
+        def seqeq(seq, val):
+            eq(f.parsesequence(seq), val)
+        
+        seqeq('5-55', range(5, 56))
+        seqeq('90-108', range(90, 101)+range(101, 109, 2))
+        seqeq('90-108', range(90, 101)+range(101, 109, 2))
+        
+        seqeq('10:10', range(10, 20))
+        seqeq('10:+10', range(10, 20))
+        seqeq('101:10', range(101, 121, 2))
+
+        seqeq('cur', [99])
+        seqeq('.', [99])
+        seqeq('prev', [98])
+        seqeq('next', [100])
+        seqeq('cur:-3', [97, 98, 99])
+        seqeq('first-cur', range(5, 100))
+        seqeq('150-last', range(151, 201, 2))
+        seqeq('prev-next', [98, 99, 100])
+
+        lowprimes = [5, 7, 11, 13, 17, 19, 23, 29]
+        lowcompos = [x for x in range(5, 31) if not x in lowprimes ]
+        f.putsequences({'cur': [5],
+                        'lowprime': lowprimes,
+                        'lowcompos': lowcompos})
+        seqs = readFile(os.path.join(_mhpath, 'wide', '.mh_sequences'))
+        seqs = sortLines(seqs)
+        eq(seqs, ["cur: 5",
+                  "lowcompos: 6 8-10 12 14-16 18 20-22 24-28 30",
+                  "lowprime: 5 7 11 13 17 19 23 29"])
+
+        seqeq('lowprime', lowprimes)
+        seqeq('lowprime:1', [5])
+        seqeq('lowprime:2', [5, 7])
+        seqeq('lowprime:-2', [23, 29])
+
+        ## Not supported
+        #seqeq('lowprime:first', [5])
+        #seqeq('lowprime:last', [29])
+        #seqeq('lowprime:prev', [29])
+        #seqeq('lowprime:next', [29])
+
+    def test_modify(self):
+        mh = getMH()
+        eq = self.assertEquals
+
+        mh.makefolder("dummy1")
+        self.assert_("dummy1" in mh.listfolders())
+        path = os.path.join(_mhpath, "dummy1")
+        self.assert_(os.path.exists(path))
+        
+        f = mh.openfolder('dummy1')
+        def create(n):
+            msg = "From: foo\nSubject: %s\n\nDummy Message %s\n" % (n,n)
+            f.createmessage(n, StringIO.StringIO(msg))
+
+        create(7)
+        create(8)
+        create(9)
+        
+        eq(readFile(f.getmessagefilename(9)),
+           "From: foo\nSubject: 9\n\nDummy Message 9\n")
+
+        eq(f.listmessages(), [7, 8, 9])
+        files = os.listdir(path)
+        files.sort()
+        eq(files, ['7', '8', '9']) 
+
+        f.removemessages(['7', '8'])
+        files = os.listdir(path)
+        files.sort()
+        eq(files, [',7', ',8', '9'])
+        eq(f.listmessages(), [9])
+        create(10)
+        create(11)
+        create(12)
+        
+        mh.makefolder("dummy2")
+        f2 = mh.openfolder("dummy2")
+        eq(f2.listmessages(), [])
+        f.movemessage(10, f2, 3)
+        f.movemessage(11, f2, 5)
+        eq(f.listmessages(), [9, 12])
+        eq(f2.listmessages(), [3, 5])
+        eq(readFile(f2.getmessagefilename(3)),
+           "From: foo\nSubject: 10\n\nDummy Message 10\n")
+        
+        f.copymessage(9, f2, 4)
+        eq(f.listmessages(), [9, 12])
+        eq(readFile(f2.getmessagefilename(4)),
+           "From: foo\nSubject: 9\n\nDummy Message 9\n")
+        
+        f.refilemessages([9, 12], f2)
+        eq(f.listmessages(), [])
+        eq(f2.listmessages(), [3, 4, 5, 6, 7])
+        eq(readFile(f2.getmessagefilename(7)),
+           "From: foo\nSubject: 12\n\nDummy Message 12\n")
+        # XXX This should check that _copysequences does the right thing.
+
+        mh.deletefolder('dummy1')
+        mh.deletefolder('dummy2')
+        self.assert_('dummy1' not in mh.listfolders())
+        self.assert_(not os.path.exists(path))
+
+    def test_read(self):
+        mh = getMH()
+        eq = self.assertEquals
+        
+        f = mh.openfolder('inbox')
+        msg = f.openmessage(1)
+        # Check some basic stuff from rfc822
+        eq(msg.getheader('From'), "Mrs. Premise")
+        eq(msg.getheader('To'), "Mrs. Conclusion")
+
+        # Okay, we have the right message.  Let's check the stuff from
+        # mhlib.
+        lines = sortLines(msg.getheadertext())
+        eq(lines, ["Date: 18 July 2001", 
+                   "From: Mrs. Premise",
+                   "To: Mrs. Conclusion"])
+        lines = sortLines(msg.getheadertext(lambda h: len(h)==4))
+        eq(lines, ["Date: 18 July 2001", 
+                   "From: Mrs. Premise"])
+        eq(msg.getbodytext(), "Hullo, Mrs. Conclusion!\n\n")
+        eq(msg.getbodytext(0), "Hullo, Mrs. Conclusion!\n\n")
+        
+        # XXXX there should be a better way to reclaim the file handle
+        msg.fp.close()
+        del msg
+
+run_unittest(MhlibTests)