Re-write the mailbox test suite to use PyUnit. Cover a lot more ground

for the Maildir mailbox format.  This still does not address other mailbox
formats.

Lib/test/output/test_mailbox

 test_mailbox
-newly created maildir contains 0 messages

Lib/test/test_mailbox.py

 import mailbox
 import os
 import test_support
+import time
+import unittest
 
-# cleanup
+# cleanup earlier tests
 try:
     os.unlink(test_support.TESTFN)
 except os.error:
     pass
 
-# create a new maildir mailbox to work with:
-curdir = os.path.join(test_support.TESTFN, "cur")
-newdir = os.path.join(test_support.TESTFN, "new")
-try:
-    os.mkdir(test_support.TESTFN)
-    os.mkdir(curdir)
-    os.mkdir(newdir)
 
-    # Test for regression on bug #117490:
-    # http://sourceforge.net/bugs/?func=detailbug&bug_id=117490&group_id=5470
-    # Make sure the boxes attribute actually gets set.
-    mbox = mailbox.Maildir(test_support.TESTFN)
-    mbox.boxes
-    print "newly created maildir contains", len(mbox.boxes), "messages"
+DUMMY_MESSAGE = """\
+From: some.body@dummy.domain
+To: me@my.domain
+
+This is a dummy message.
+"""
+
+
+class MaildirTestCase(unittest.TestCase):
+
+    def setUp(self):
+        # create a new maildir mailbox to work with:
+        self._dir = test_support.TESTFN
+        os.mkdir(self._dir)
+        os.mkdir(os.path.join(self._dir, "cur"))
+        os.mkdir(os.path.join(self._dir, "tmp"))
+        os.mkdir(os.path.join(self._dir, "new"))
+        self._counter = 1
+        self._msgfiles = []
+
+    def tearDown(self):
+        map(os.unlink, self._msgfiles)
+        os.rmdir(os.path.join(self._dir, "cur"))
+        os.rmdir(os.path.join(self._dir, "tmp"))
+        os.rmdir(os.path.join(self._dir, "new"))
+        os.rmdir(self._dir)
+
+    def createMessage(self, dir):
+        t = int(time.time())
+        pid = self._counter
+        self._counter += 1
+        filename = "%s.%s.myhostname.mydomain" % (t, pid)
+        tmpname = os.path.join(self._dir, "tmp", filename)
+        newname = os.path.join(self._dir, dir, filename)
+        fp = open(tmpname, "w")
+        self._msgfiles.append(tmpname)
+        fp.write(DUMMY_MESSAGE)
+        fp.close()
+        os.link(tmpname, newname)
+        self._msgfiles.append(newname)
+
+    def test_empty_maildir(self):
+        """Test an empty maildir mailbox"""
+        # Test for regression on bug #117490:
+        # Make sure the boxes attribute actually gets set.
+        self.mbox = mailbox.Maildir(test_support.TESTFN)
+        self.assert_(hasattr(self.mbox, "boxes"))
+        self.assert_(len(self.mbox.boxes) == 0)
+        self.assert_(self.mbox.next() is None)
+        self.assert_(self.mbox.next() is None)
+
+    def test_nonempty_maildir_cur(self):
+        self.createMessage("cur")
+        self.mbox = mailbox.Maildir(test_support.TESTFN)
+        self.assert_(len(self.mbox.boxes) == 1)
+        self.assert_(self.mbox.next() is not None)
+        self.assert_(self.mbox.next() is None)
+        self.assert_(self.mbox.next() is None)
+
+    def test_nonempty_maildir_new(self):
+        self.createMessage("new")
+        self.mbox = mailbox.Maildir(test_support.TESTFN)
+        self.assert_(len(self.mbox.boxes) == 1)
+        self.assert_(self.mbox.next() is not None)
+        self.assert_(self.mbox.next() is None)
+        self.assert_(self.mbox.next() is None)
+
+    def test_nonempty_maildir_both(self):
+        self.createMessage("cur")
+        self.createMessage("new")
+        self.mbox = mailbox.Maildir(test_support.TESTFN)
+        self.assert_(len(self.mbox.boxes) == 2)
+        self.assert_(self.mbox.next() is not None)
+        self.assert_(self.mbox.next() is not None)
+        self.assert_(self.mbox.next() is None)
+        self.assert_(self.mbox.next() is None)
 
     # XXX We still need more tests!
 
-finally:
-    try: os.rmdir(newdir)
-    except os.error: pass
-    try: os.rmdir(curdir)
-    except os.error: pass
-    try: os.rmdir(test_support.TESTFN)
-    except os.error: pass
+
+test_support.run_unittest(MaildirTestCase)