diff --git a/hgext/notify.py b/hgext/notify.py
--- a/hgext/notify.py
+++ b/hgext/notify.py
@@ -105,6 +105,9 @@ notify.diffstat
 notify.merge
   If True, send notifications for merge changesets. Default: True.
 
+notify.mbox
+  If set, append mails to this mbox file instead of sending. Default: None.
+
 If set, the following entries will also be used to customize the notifications:
 
 email.from
@@ -156,6 +159,7 @@ class notifier(object):
         self.stripcount = int(self.ui.config('notify', 'strip', 0))
         self.root = self.strip(self.repo.root)
         self.domain = self.ui.config('notify', 'domain')
+        self.mbox = self.ui.config('notify', 'mbox')
         self.test = self.ui.configbool('notify', 'test', True)
         self.charsets = mail._charsets(self.ui)
         self.subs = self.subscribers()
@@ -288,7 +292,7 @@ class notifier(object):
             self.ui.status(_('notify: sending %d subscribers %d changes\n') %
                            (len(self.subs), count))
             mail.sendmail(self.ui, util.email(msg['From']),
-                          self.subs, msgtext)
+                          self.subs, msgtext, mbox=self.mbox)
 
     def diff(self, ctx, ref=None):
 
diff --git a/mercurial/mail.py b/mercurial/mail.py
--- a/mercurial/mail.py
+++ b/mercurial/mail.py
@@ -114,8 +114,8 @@ def connect(ui, mbox=None):
         return _smtp(ui)
     return lambda s, r, m: _sendmail(ui, s, r, m)
 
-def sendmail(ui, sender, recipients, msg):
-    send = connect(ui)
+def sendmail(ui, sender, recipients, msg, mbox=None):
+    send = connect(ui, mbox=mbox)
     return send(sender, recipients, msg)
 
 def validateconfig(ui):
diff --git a/tests/test-notify.t b/tests/test-notify.t
--- a/tests/test-notify.t
+++ b/tests/test-notify.t
@@ -113,6 +113,9 @@
   notify.merge
     If True, send notifications for merge changesets. Default: True.
   
+  notify.mbox
+    If set, append mails to this mbox file instead of sending. Default: None.
+  
   If set, the following entries will also be used to customize the
   notifications:
   
@@ -350,7 +353,7 @@ test merge
   description: merge
   (run 'hg update' to get a working copy)
 
-truncate multi-byte subject
+non-ascii content and truncation of multi-byte subject
 
   $ cat <<EOF >> $HGRCPATH
   > [notify]
@@ -395,3 +398,54 @@ truncate multi-byte subject
    a
   +a
   (run 'hg update' to get a working copy)
+
+long lines
+
+  $ cat <<EOF >> $HGRCPATH
+  > [notify]
+  > maxsubject = 67
+  > test = False
+  > mbox = mbox
+  > EOF
+  $ python -c 'print "no" * 500' >> a/a
+  $ hg --cwd a commit -A -m "long line"
+  $ hg --traceback --cwd b pull ../a
+  pulling from ../a
+  searching for changes
+  adding changesets
+  adding manifests
+  adding file changes
+  added 1 changesets with 1 changes to 1 files
+  notify: sending 2 subscribers 1 changes
+  (run 'hg update' to get a working copy)
+  $ python -c 'import sys,re; print re.sub("\n\t", " ", file("b/mbox").read()),'
+  From test@test.com ... ... .. ..:..:.. .... (re)
+  Content-Type: text/plain; charset="us-ascii"
+  MIME-Version: 1.0
+  Content-Transfer-Encoding: 7bit
+  X-Test: foo
+  Date: * (glob)
+  Subject: long line
+  From: test@test.com
+  X-Hg-Notification: changeset e0be44cf638b
+  Message-Id: <hg.e0be44cf638b.*.*@*> (glob)
+  To: baz@test.com, foo@bar
+  
+  changeset e0be44cf638b in b
+  description: long line
+  diffstat:
+  
+   a |  1 +
+   1 files changed, 1 insertions(+), 0 deletions(-)
+  
+  diffs (8 lines):
+  
+  diff -r 7ea05ad269dc -r e0be44cf638b a
+  --- a/a	Thu Jan 01 00:00:00 1970 +0000
+  +++ b/a	Thu Jan 01 00:00:00 1970 +0000
+  @@ -1,3 +1,4 @@
+   a
+   a
+   a
+  +nononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononononono
+