diff --git a/test_archivemail.py b/test_archivemail.py
index a65f6cc..3615712 100755
--- a/test_archivemail.py
+++ b/test_archivemail.py
@@ -473,12 +473,81 @@ class TestParseIMAPUrl(unittest.TestCase):
 
 ########## acceptance testing ###########
 
-class TestArchiveMbox(TestCaseInTempdir):
+class TestArchive(TestCaseInTempdir):
+    """Base class defining helper functions for doing test archiving runs."""
+    mbox = None
+    good_archive = good_mbox = None
+
+    def verify(self):
+        assert(os.path.exists(self.mbox))
+        if self.good_mbox is not None:
+            assertEqualContent(self.mbox, self.good_mbox)
+        else:
+            self.assertEqual(os.path.getsize(self.mbox), 0)
+        archive_name = self.mbox + "_archive"
+        if not archivemail.options.no_compress:
+            archive_name += ".gz"
+            iszipped = True
+        else:
+            assert(not os.path.exists(archive_name + ".gz"))
+            iszipped = False
+        if self.good_archive is not None:
+            assertEqualContent(archive_name, self.good_archive, iszipped)
+        else:
+            assert(not os.path.exists(archive_name))
+
+    def make_old_mbox(self, body=None, headers=None, messages=1, old_archive=False):
+        """Make an old mbox, optionally an existing archive, and make a reference
+        archive like it should look like after archivemail has run."""
+        self.mbox = make_mbox(body, headers, 181*24, messages)
+        archive_changes = not (archivemail.options.dry_run or
+                archivemail.options.delete_old_mail)
+        mbox_no_changes = archivemail.options.dry_run or archivemail.options.copy_old_mail
+        if old_archive:
+            self.good_archive = make_old_archive(self.mbox)
+            if archive_changes:
+                append_file(self.mbox, self.good_archive)
+            if mbox_no_changes:
+                self.good_mbox = tempfile.mkstemp()[1]
+                shutil.copyfile(self.mbox, self.good_mbox)
+            return
+        if archive_changes:
+            self.good_archive = tempfile.mkstemp()[1]
+            shutil.copyfile(self.mbox, self.good_archive)
+            if mbox_no_changes:
+                self.good_mbox = self.good_archive
+        elif mbox_no_changes:
+            self.good_mbox = tempfile.mkstemp()[1]
+            shutil.copyfile(self.mbox, self.good_mbox)
+
+    def make_mixed_mbox(self, body=None, headers=None, messages=1, old_archive=False):
+        """Make a mixed mbox, optionally an existing archive, a reference archive
+        like it should look like after archivemail has run, and a reference mbox
+        like it should remain after archivemail has run."""
+        self.make_old_mbox(body, headers, messages=messages, old_archive=old_archive)
+        new_mbox_name = make_mbox(body, headers, 179*24, messages)
+        append_file(new_mbox_name, self.mbox)
+        if self.good_mbox is None:
+            self.good_mbox = new_mbox_name
+        else:
+            if self.good_mbox == self.good_archive:
+                self.good_mbox = tempfile.mkstemp()[1]
+                shutil.copyfile(self.mbox, self.good_mbox)
+            else:
+                append_file(new_mbox_name, self.good_mbox)
+
+    def make_new_mbox(self, body=None, headers=None, messages=1, old_archive=False):
+        """Make a new mbox, optionally an exiting archive, and a reference mbox
+        like it should remain after archivemail has run."""
+        self.mbox = make_mbox(body, headers, 179*24, messages)
+        self.good_mbox = tempfile.mkstemp()[1]
+        shutil.copyfile(self.mbox, self.good_mbox)
+        if old_archive:
+            self.good_archive = make_old_archive(self.mbox)
+
+
+class TestArchiveMbox(TestArchive):
     """archiving should work based on the date of messages given"""
-    old_mbox = None
-    new_mbox = None
-    copy_name = None
-    mbox_name = None
 
     def setUp(self):
         self.oldopts = copy.copy(archivemail.options)
@@ -487,31 +556,18 @@ class TestArchiveMbox(TestCaseInTempdir):
  
     def testOld(self):
         """archiving an old mailbox"""
-        self.mbox_name = make_mbox(messages=3, hours_old=(24 * 181))
-        self.mbox_mode = os.stat(self.mbox_name)[stat.ST_MODE]
-        self.copy_name = tempfile.mkstemp()[1]
-        shutil.copyfile(self.mbox_name, self.copy_name)
-        archivemail.archive(self.mbox_name)
-        assert(os.path.exists(self.mbox_name))
-        self.assertEqual(os.path.getsize(self.mbox_name), 0)
-        new_mode = os.stat(self.mbox_name)[stat.ST_MODE]
-        self.assertEqual(self.mbox_mode, new_mode)
-        archive_name = self.mbox_name + "_archive.gz"
-        assertEqualContent(archive_name, self.copy_name, zipfirst=True)
+        self.make_old_mbox(messages=3)
+        archivemail.archive(self.mbox)
+        self.verify()
 
     def testOldFromInBody(self):
         """archiving an old mailbox with 'From ' in the body"""
         body = """This is a message with ^From at the start of a line
 From is on this line
 This is after the ^From line"""
-        self.mbox_name = make_mbox(messages=3, hours_old=(24 * 181), body=body)
-        self.copy_name = tempfile.mkstemp()[1]
-        shutil.copyfile(self.mbox_name, self.copy_name)
-        archivemail.archive(self.mbox_name)
-        assert(os.path.exists(self.mbox_name))
-        self.assertEqual(os.path.getsize(self.mbox_name), 0)
-        archive_name = self.mbox_name + "_archive.gz"
-        assertEqualContent(archive_name, self.copy_name, zipfirst=True)
+        self.make_old_mbox(messages=3, body=body)
+        archivemail.archive(self.mbox)
+        self.verify()
 
     def testDateSystem(self):
         """test that the --date option works as expected"""
@@ -546,49 +602,21 @@ This is after the ^From line"""
 
     def testMixed(self):
         """archiving a mixed mailbox"""
-        self.new_mbox = make_mbox(messages=3, hours_old=(24 * 179))
-        self.old_mbox = make_mbox(messages=3, hours_old=(24 * 181))
-        self.mbox_name = tempfile.mkstemp()[1]
-        shutil.copyfile(self.new_mbox, self.mbox_name)
-        append_file(self.old_mbox, self.mbox_name)
-        archivemail.archive(self.mbox_name)
-        assertEqualContent(self.mbox_name, self.new_mbox)
-        archive_name = self.mbox_name + "_archive.gz"
-        assertEqualContent(archive_name, self.old_mbox, zipfirst=True)
+        self.make_mixed_mbox(messages=3)
+        archivemail.archive(self.mbox)
+        self.verify()
 
     def testNew(self):
         """archiving a new mailbox"""
-        self.mbox_name = make_mbox(messages=3, hours_old=(24 * 179))
-        self.mbox_mode = os.stat(self.mbox_name)[stat.ST_MODE]
-        self.copy_name = tempfile.mkstemp()[1]
-        shutil.copyfile(self.mbox_name, self.copy_name)
-        archivemail.archive(self.mbox_name)
-        assertEqualContent(self.mbox_name, self.copy_name)
-        new_mode = os.stat(self.mbox_name)[stat.ST_MODE]
-        self.assertEqual(self.mbox_mode, new_mode)
-        archive_name = self.mbox_name + "_archive.gz"
-        assert(not os.path.exists(archive_name))
-
+        self.make_new_mbox(messages=3)
+        archivemail.archive(self.mbox)
+        self.verify()
 
     def testOldExisting(self):
         """archiving an old mailbox with an existing archive"""
-        self.mbox_name = make_mbox(messages=3, hours_old=(24 * 181))
-        self.mbox_mode = os.stat(self.mbox_name)[stat.ST_MODE]
-        self.copy_name = tempfile.mkstemp()[1]
-        archive_name = self.mbox_name + "_archive.gz"
-        shutil.copyfile(self.mbox_name, self.copy_name)
-        fp1 = open(self.mbox_name, "r")
-        fp2 = gzip.GzipFile(archive_name, "w")
-        shutil.copyfileobj(fp1, fp2) # archive has 3 msgs
-        fp2.close()
-        fp1.close()
-        append_file(self.mbox_name, self.copy_name) # copy now has 6 msgs
-        archivemail.archive(self.mbox_name)
-        assert(os.path.exists(self.mbox_name))
-        self.assertEqual(os.path.getsize(self.mbox_name), 0)
-        new_mode = os.stat(self.mbox_name)[stat.ST_MODE]
-        self.assertEqual(self.mbox_mode, new_mode)
-        assertEqualContent(archive_name, self.copy_name, zipfirst=True)
+        self.make_old_mbox(messages=3, old_archive=True)
+        archivemail.archive(self.mbox)
+        self.verify()
 
     def testOldWeirdHeaders(self):
         """archiving old mailboxes with weird headers"""
@@ -631,19 +659,16 @@ This is after the ^From line"""
                 'Resent-Date'  : '',
             },
         )
-        fd, self.mbox_name = tempfile.mkstemp()
+        fd, self.mbox = tempfile.mkstemp()
         fp = os.fdopen(fd, "w")
         for headers in weird_headers:
             msg_text = make_message(default_headers=headers)
             fp.write(msg_text*2)
         fp.close()
-        self.copy_name = tempfile.mkstemp()[1]
-        shutil.copyfile(self.mbox_name, self.copy_name)
-        archivemail.archive(self.mbox_name)
-        assert(os.path.exists(self.mbox_name))
-        self.assertEqual(os.path.getsize(self.mbox_name), 0)
-        archive_name = self.mbox_name + "_archive.gz"
-        assertEqualContent(archive_name, self.copy_name, zipfirst=True)
+        self.good_archive = tempfile.mkstemp()[1]
+        shutil.copyfile(self.mbox, self.good_archive)
+        archivemail.archive(self.mbox)
+        self.verify()
 
     def tearDown(self):
         archivemail.options = self.oldopts
@@ -655,42 +680,24 @@ class TestArchiveMboxTimestamp(TestCaseInTempdir):
     def setUp(self):
         super(TestArchiveMboxTimestamp, self).setUp() 
         archivemail.options.quiet = 1
+        self.mbox_name = make_mbox(messages=3, hours_old=(24 * 180))
+        self.mtime = os.path.getmtime(self.mbox_name) - 66
+        self.atime = os.path.getatime(self.mbox_name) - 88
+        os.utime(self.mbox_name, (self.atime, self.mtime))
 
     def testNew(self):
         """mbox timestamps should not change after no archival"""
-        self.mbox_name = make_mbox(messages=3, hours_old=(24 * 179))
-        self.mtime = os.path.getmtime(self.mbox_name) - 66
-        self.atime = os.path.getatime(self.mbox_name) - 88
-        os.utime(self.mbox_name, (self.atime, self.mtime))
+        archivemail.options.days_old_max = 181
         archivemail.archive(self.mbox_name)
-        assert(os.path.exists(self.mbox_name))
-        new_atime = os.path.getatime(self.mbox_name)
-        new_mtime = os.path.getmtime(self.mbox_name)
-        self.assertAlmostEqual(self.mtime, new_mtime, utimes_precision)
-        self.assertAlmostEqual(self.atime, new_atime, utimes_precision)
-
-    def testMixed(self):
-        """mbox timestamps should not change after semi-archival"""
-        self.mbox_name = make_mbox(messages=3, hours_old=(24 * 181))
-        self.mtime = os.path.getmtime(self.mbox_name) - 66
-        self.atime = os.path.getatime(self.mbox_name) - 88
-        os.utime(self.mbox_name, (self.atime, self.mtime))
-        archive_name = self.mbox_name + "_archive.gz"
-        archivemail.archive(self.mbox_name)
-        assert(os.path.exists(self.mbox_name))
-        new_atime = os.path.getatime(self.mbox_name)
-        new_mtime = os.path.getmtime(self.mbox_name)
-        self.assertAlmostEqual(self.mtime, new_mtime, utimes_precision)
-        self.assertAlmostEqual(self.atime, new_atime, utimes_precision)
+        self.verify()
 
     def testOld(self):
         """mbox timestamps should not change after archival"""
-        self.mbox_name = make_mbox(messages=3, hours_old=(24 * 181))
-        self.mtime = os.path.getmtime(self.mbox_name) - 66
-        self.atime = os.path.getatime(self.mbox_name) - 88
-        os.utime(self.mbox_name, (self.atime, self.mtime))
-        archive_name = self.mbox_name + "_archive.gz"
+        archivemail.options.days_old_max = 179
         archivemail.archive(self.mbox_name)
+        self.verify()
+
+    def verify(self):
         assert(os.path.exists(self.mbox_name))
         new_atime = os.path.getatime(self.mbox_name)
         new_mtime = os.path.getmtime(self.mbox_name)
@@ -699,6 +706,8 @@ class TestArchiveMboxTimestamp(TestCaseInTempdir):
 
     def tearDown(self):
         archivemail.options.quiet = 0
+        archivemail.options.days_old_max = 180
+        os.remove(self.mbox_name)
         super(TestArchiveMboxTimestamp, self).tearDown()
 
 
@@ -767,7 +776,7 @@ class TestArchiveMboxSuffix(unittest.TestCase):
         archivemail.options.archive_suffix = self.old_suffix
 
 
-class TestArchiveDryRun(TestCaseInTempdir):
+class TestArchiveDryRun(TestArchive):
     """make sure the 'dry-run' option works"""
     def setUp(self):
         super(TestArchiveDryRun, self).setUp()
@@ -776,13 +785,9 @@ class TestArchiveDryRun(TestCaseInTempdir):
 
     def testOld(self):
         """archiving an old mailbox with the 'dry-run' option"""
-        self.mbox_name = make_mbox(messages=3, hours_old=(24 * 181))
-        self.copy_name = tempfile.mkstemp()[1]
-        shutil.copyfile(self.mbox_name, self.copy_name)
-        archivemail.archive(self.mbox_name)
-        assertEqualContent(self.mbox_name, self.copy_name)
-        archive_name = self.mbox_name + "_archive.gz"
-        assert(not os.path.exists(archive_name))
+        self.make_old_mbox(messages=3)
+        archivemail.archive(self.mbox)
+        self.verify()
 
     def tearDown(self):
         archivemail.options.dry_run = 0
@@ -790,13 +795,8 @@ class TestArchiveDryRun(TestCaseInTempdir):
         super(TestArchiveDryRun, self).tearDown()
 
 
-class TestArchiveDelete(TestCaseInTempdir):
+class TestArchiveDelete(TestArchive):
     """make sure the 'delete' option works"""
-    old_mbox = None
-    new_mbox = None
-    copy_name = None
-    mbox_name = None
-
     def setUp(self):
         super(TestArchiveDelete, self).setUp()
         archivemail.options.quiet = 1
@@ -804,36 +804,21 @@ class TestArchiveDelete(TestCaseInTempdir):
 
     def testNew(self):
         """archiving a new mailbox with the 'delete' option"""
-        self.mbox_name = make_mbox(messages=3, hours_old=(24 * 179))
-        self.copy_name = tempfile.mkstemp()[1]
-        shutil.copyfile(self.mbox_name, self.copy_name)
-        archivemail.archive(self.mbox_name)
-        assertEqualContent(self.mbox_name, self.copy_name)
-        archive_name = self.mbox_name + "_archive.gz"
-        assert(not os.path.exists(archive_name))
+        self.make_new_mbox(messages=3)
+        archivemail.archive(self.mbox)
+        self.verify()
 
     def testMixed(self):
         """archiving a mixed mailbox with the 'delete' option"""
-        self.new_mbox = make_mbox(messages=3, hours_old=(24 * 179))
-        self.old_mbox = make_mbox(messages=3, hours_old=(24 * 181))
-        self.mbox_name = tempfile.mkstemp()[1]
-        shutil.copyfile(self.new_mbox, self.mbox_name)
-        append_file(self.old_mbox, self.mbox_name)
-        archivemail.archive(self.mbox_name)
-        assertEqualContent(self.mbox_name, self.new_mbox)
-        archive_name = self.mbox_name + "_archive.gz"
-        assert(not os.path.exists(archive_name))
+        self.make_mixed_mbox(messages=3)
+        archivemail.archive(self.mbox)
+        self.verify()
 
     def testOld(self):
         """archiving an old mailbox with the 'delete' option"""
-        self.mbox_name = make_mbox(messages=3, hours_old=(24 * 181))
-        self.copy_name = tempfile.mkstemp()[1]
-        shutil.copyfile(self.mbox_name, self.copy_name)
-        archivemail.archive(self.mbox_name)
-        assert(os.path.exists(self.mbox_name))
-        self.assertEqual(os.path.getsize(self.mbox_name), 0)
-        archive_name = self.mbox_name + "_archive.gz"
-        assert(not os.path.exists(archive_name))
+        self.make_old_mbox(messages=3)
+        archivemail.archive(self.mbox)
+        self.verify()
 
     def tearDown(self):
         archivemail.options.delete_old_mail = 0
@@ -841,13 +826,8 @@ class TestArchiveDelete(TestCaseInTempdir):
         super(TestArchiveDelete, self).tearDown()
 
 
-class TestArchiveCopy(TestCaseInTempdir):
+class TestArchiveCopy(TestArchive):
     """make sure the 'copy' option works"""
-    old_mbox = None
-    new_mbox = None
-    mbox_backup_name = None
-    mbox_name = None
-
     def setUp(self):
         super(TestArchiveCopy, self).setUp()
         archivemail.options.quiet = 1
@@ -855,38 +835,21 @@ class TestArchiveCopy(TestCaseInTempdir):
 
     def testNew(self):
         """archiving a new mailbox with the 'copy' option"""
-        self.mbox_name = make_mbox(messages=3, hours_old=(24 * 179))
-        self.mbox_backup_name = tempfile.mkstemp()[1]
-        shutil.copyfile(self.mbox_name, self.mbox_backup_name)
-        archivemail.archive(self.mbox_name)
-        assertEqualContent(self.mbox_name, self.mbox_backup_name)
-        archive_name = self.mbox_name + "_archive.gz"
-        assert(not os.path.exists(archive_name))
-        self.tearDown()
+        self.make_new_mbox(messages=3)
+        archivemail.archive(self.mbox)
+        self.verify()
 
     def testMixed(self):
         """archiving a mixed mailbox with the 'copy' option"""
-        self.new_mbox = make_mbox(messages=3, hours_old=(24 * 179))
-        self.old_mbox = make_mbox(messages=3, hours_old=(24 * 181))
-        self.mbox_name = tempfile.mkstemp()[1]
-        shutil.copyfile(self.new_mbox, self.mbox_name)
-        append_file(self.old_mbox, self.mbox_name)
-        self.mbox_backup_name = tempfile.mkstemp()[1]
-        shutil.copyfile(self.mbox_name, self.mbox_backup_name)
-        archivemail.archive(self.mbox_name)
-        assertEqualContent(self.mbox_name, self.mbox_backup_name)
-        archive_name = self.mbox_name + "_archive.gz"
-        assertEqualContent(archive_name, self.old_mbox, zipfirst=True)
+        self.make_mixed_mbox(messages=3)
+        archivemail.archive(self.mbox)
+        self.verify()
 
     def testOld(self):
         """archiving an old mailbox with the 'copy' option"""
-        self.mbox_name = make_mbox(messages=3, hours_old=(24 * 181))
-        self.mbox_backup_name = tempfile.mkstemp()[1]
-        shutil.copyfile(self.mbox_name, self.mbox_backup_name)
-        archivemail.archive(self.mbox_name)
-        assertEqualContent(self.mbox_name, self.mbox_backup_name)
-        archive_name = self.mbox_name + "_archive.gz"
-        assertEqualContent(archive_name, self.mbox_name, zipfirst=True)
+        self.make_old_mbox(messages=3)
+        archivemail.archive(self.mbox)
+        self.verify()
 
     def tearDown(self):
         archivemail.options.copy_old_mail = 0
@@ -941,7 +904,7 @@ class TestArchiveMboxOutputDir(unittest.TestCase):
         archivemail.options.output_dir = None
 
 
-class TestArchiveMboxUncompressed(TestCaseInTempdir):
+class TestArchiveMboxUncompressed(TestArchive):
     """make sure that the 'no_compress' option works"""
     mbox_name = None
     new_mbox = None
@@ -955,63 +918,27 @@ class TestArchiveMboxUncompressed(TestCaseInTempdir):
 
     def testOld(self):
         """archiving an old mailbox uncompressed"""
-        self.mbox_name = make_mbox(messages=3, hours_old=(24 * 181))
-        self.mbox_mode = os.stat(self.mbox_name)[stat.ST_MODE]
-        self.copy_name = tempfile.mkstemp()[1]
-        shutil.copyfile(self.mbox_name, self.copy_name)
-        archivemail.archive(self.mbox_name)
-        assert(os.path.exists(self.mbox_name))
-        self.assertEqual(os.path.getsize(self.mbox_name), 0)
-        new_mode = os.stat(self.mbox_name)[stat.ST_MODE]
-        self.assertEqual(self.mbox_mode, new_mode)
-        archive_name = self.mbox_name + "_archive"
-        assertEqualContent(archive_name, self.copy_name)
-        assert(not os.path.exists(archive_name + ".gz"))
+        self.make_old_mbox(messages=3)
+        archivemail.archive(self.mbox)
+        self.verify()
 
     def testNew(self):
         """archiving a new mailbox uncompressed"""
-        self.mbox_name = make_mbox(messages=3, hours_old=(24 * 179))
-        self.mbox_mode = os.stat(self.mbox_name)[stat.ST_MODE]
-        self.copy_name = tempfile.mkstemp()[1]
-        shutil.copyfile(self.mbox_name, self.copy_name)
-        archivemail.archive(self.mbox_name)
-        assertEqualContent(self.mbox_name, self.copy_name)
-        new_mode = os.stat(self.mbox_name)[stat.ST_MODE]
-        self.assertEqual(self.mbox_mode, new_mode)
-        archive_name = self.mbox_name + "_archive"
-        assert(not os.path.exists(archive_name))
-        assert(not os.path.exists(archive_name + ".gz"))
+        self.make_new_mbox(messages=3)
+        archivemail.archive(self.mbox)
+        self.verify()
 
     def testMixed(self):
         """archiving a mixed mailbox uncompressed"""
-        self.new_mbox = make_mbox(messages=3, hours_old=(24 * 179))
-        self.old_mbox = make_mbox(messages=3, hours_old=(24 * 181))
-        self.mbox_name = tempfile.mkstemp()[1]
-        shutil.copyfile(self.new_mbox, self.mbox_name)
-        append_file(self.old_mbox, self.mbox_name)
-        archivemail.archive(self.mbox_name)
-        assertEqualContent(self.mbox_name, self.new_mbox)
-        archive_name = self.mbox_name + "_archive"
-        assertEqualContent(archive_name, self.old_mbox)
-        assert(not os.path.exists(archive_name + ".gz"))
+        self.make_mixed_mbox(messages=3)
+        archivemail.archive(self.mbox)
+        self.verify()
 
     def testOldExists(self):
         """archiving an old mailbox uncopressed with an existing archive"""
-        self.mbox_name = make_mbox(messages=3, hours_old=(24 * 181))
-        self.mbox_mode = os.stat(self.mbox_name)[stat.ST_MODE]
-        self.copy_name = tempfile.mkstemp()[1]
-        archive_name = self.mbox_name + "_archive"
-        shutil.copyfile(self.mbox_name, self.copy_name)
-        shutil.copyfile(self.mbox_name, archive_name) # archive has 3 msgs
-        append_file(self.mbox_name, self.copy_name) # copy now has 6 msgs
-        archivemail.archive(self.mbox_name)
-        assert(os.path.exists(self.mbox_name))
-        self.assertEqual(os.path.getsize(self.mbox_name), 0)
-        new_mode = os.stat(self.mbox_name)[stat.ST_MODE]
-        self.assertEqual(self.mbox_mode, new_mode)
-        archive_name = self.mbox_name + "_archive"
-        assertEqualContent(archive_name, self.copy_name)
-        assert(not os.path.exists(archive_name + ".gz"))
+        self.make_old_mbox(messages=3, old_archive=True)
+        archivemail.archive(self.mbox)
+        self.verify()
 
     def tearDown(self):
         archivemail.options.quiet = 0
@@ -1120,7 +1047,7 @@ def append_file(source, dest):
     assert(os.path.isfile(dest))
     read = open(source, "r")
     write = open(dest, "a+")
-    write.writelines(read.readlines())
+    shutil.copyfileobj(read,write)
     read.close()
     write.close()
 
@@ -1136,6 +1063,31 @@ def make_mbox(body=None, headers=None, hours_old=0, messages=1):
     file.close()
     return name
 
+def make_old_archive(mailbox_name):
+    """Make an mbox archive like if archivemail has already archived the given
+    mailbox in the past. Also make an uncompressed copy of this archive and
+    return its name."""
+    old_archive_name = archivemail.make_archive_name(mailbox_name)
+    fd, archive_name = tempfile.mkstemp()
+    fp = os.fdopen(fd, "w")
+    if archivemail.options.no_compress:
+        oldfd = os.open(old_archive_name, os.O_WRONLY|os.O_EXCL|os.O_CREAT)
+        oldfp = os.fdopen(oldfd, "w")
+    else:
+        old_archive_name += ".gz"
+        oldfd = os.open(old_archive_name, os.O_WRONLY|os.O_EXCL|os.O_CREAT)
+        oldrawfp = os.fdopen(oldfd, "w")
+        oldfp = gzip.GzipFile(fileobj=oldrawfp)
+    for count in range(3):
+        msg = make_message(hours_old=24*360)
+        oldfp.write(msg)
+        fp.write(msg)
+    oldfp.close()
+    fp.close()
+    if not archivemail.options.no_compress:
+        oldrawfp.close()
+    return archive_name
+
 def assertEqualContent(firstfile, secondfile, zipfirst=False):
     """Verify that the two files exist and have identical content. If zipfirst
     is True, assume that firstfile is gzip-compressed."""