Let's test that exporting a event with attendees works just
fine. First step is creating a event:

  >>> from DateTime import DateTime
  >>> _ = self.portal.invokeFactory('Event', 'event1',
  ...      attendees=('Foo <foo@bar.com>', 'Bar <bar@baz.com>'),
  ...      location='Vienna',
  ...      title='Plone Conference 2004',
  ...      startDate=DateTime('2004-09-20 01:00:00 GMT+0'),
  ...      endDate=DateTime('2004-09-24 04:00:00 GMT+0'))

Now let's export it:

  >>> print self.cal.exportCalendar(events=[self.portal.event1])
  BEGIN:VCALENDAR
  PRODID:-//Plone/NONSGML Calendaring//EN
  VERSION:2.0
  X-WR-CALNAME:Plone site
  BEGIN:VEVENT
  ATTENDEE;CN=Foo:mailto:foo@bar.com
  ATTENDEE;CN=Bar:mailto:bar@baz.com
  DESCRIPTION:
  DTEND:20040924T040000Z
  DTSTAMP:...
  DTSTART:20040920T010000Z
  LOCATION:Vienna
  STATUS:TENTATIVE
  SUMMARY:Plone Conference 2004
  UID:event1
  END:VEVENT
  END:VCALENDAR

Using the CalendarMarshaller with the portal to export the event:

  >>> from Products.Calendaring import CalendarMarshaller
  >>> marshaller = CalendarMarshaller()
  >>> print marshaller.marshall(self.portal)[2]
  BEGIN:VCALENDAR
  PRODID:-//Plone/NONSGML Calendaring//EN
  VERSION:2.0
  X-WR-CALNAME:Plone site
  BEGIN:VEVENT
  ATTENDEE;CN=Foo:mailto:foo@bar.com
  ATTENDEE;CN=Bar:mailto:bar@baz.com
  DESCRIPTION:
  DTEND:20040924T040000Z
  DTSTAMP:...
  DTSTART:20040920T010000Z
  LOCATION:Vienna
  STATUS:TENTATIVE
  SUMMARY:Plone Conference 2004
  UID:event1
  END:VEVENT
  END:VCALENDAR

Using the EventMarshaller with the event:

  >>> from Products.Calendaring import EventMarshaller
  >>> marshaller = EventMarshaller()
  >>> print marshaller.marshall(self.portal.event1)[2]
  BEGIN:VCALENDAR
  PRODID:-//Plone/NONSGML Calendaring//EN
  VERSION:2.0
  BEGIN:VEVENT
  ATTENDEE;CN=Foo:mailto:foo@bar.com
  ATTENDEE;CN=Bar:mailto:bar@baz.com
  DESCRIPTION:
  DTEND:20040924T040000Z
  DTSTAMP:...
  DTSTART:20040920T010000Z
  LOCATION:Vienna
  STATUS:TENTATIVE
  SUMMARY:Plone Conference 2004
  UID:event1
  END:VEVENT
  END:VCALENDAR

  >>> def demarshall(marshaller, instance, data):
  ...    m = marshaller()
  ...    m.demarshall(instance, data)

This will create a new event, because the UID doesn't match any
existing object.

  >>> demarshall(CalendarMarshaller, self.portal, r"""
  ... BEGIN:VCALENDAR
  ... PRODID:-//Plone/NONSGML Calendaring//EN
  ... VERSION:2.0
  ... BEGIN:VEVENT
  ... UID:1445300814-1921707519-RID
  ... SUMMARY:Plone Symposium
  ... DESCRIPTION:Hosted by Enfold Systems
  ... LOCATION:New Orleans
  ... ATTENDEE;CN=Sidnei da Silva:mailto:sidnei@enfoldsystems.com
  ... ATTENDEE;CN=Alan Runyan:mailto:alan@enfoldsystems.com
  ... DTSTART:20050525T103000Z
  ... DTEND:20050601T200000Z
  ... STATUS:CONFIRMED
  ... END:VEVENT
  ... END:VCALENDAR
  ... """)

  >>> from Products.Calendaring import EventMarshaller
  >>> from Products.Calendaring.marshaller import _generateId
  >>> id = _generateId(uid='1445300814-1921707519-RID',
  ...                  title='Plone Symposium',
  ...                  context=self.portal)
  >>> marshaller = EventMarshaller()
  >>> print marshaller.marshall(self.portal[id])[2]
  BEGIN:VCALENDAR
  PRODID:-//Plone/NONSGML Calendaring//EN
  VERSION:2.0
  BEGIN:VEVENT
  ATTENDEE;CN=Sidnei da Silva:mailto:sidnei@enfoldsystems.com
  ATTENDEE;CN=Alan Runyan:mailto:alan@enfoldsystems.com
  DESCRIPTION:Hosted by Enfold Systems
  DTEND:20050601T200000Z
  DTSTAMP:...
  DTSTART:20050525T103000Z
  LOCATION:New Orleans
  STATUS:CONFIRMED
  SUMMARY:Plone Symposium
  UID:1445300814-1921707519-RID
  END:VEVENT
  END:VCALENDAR

This will modify the existing event, because we are using the
EventMarshaller on the object itself.

  >>> 'event1' in self.portal.objectIds()
  True

  >>> demarshall(EventMarshaller, self.portal.event1, r"""
  ... BEGIN:VCALENDAR
  ... PRODID:-//Plone/NONSGML Calendaring//EN
  ... VERSION:2.0
  ... BEGIN:VEVENT
  ... UID:2445300814-1921707519-RID
  ... SUMMARY:Plone Symposium
  ... DESCRIPTION:Hosted by Enfold Systems
  ... LOCATION:New Orleans
  ... URL;VALUE=URI:http://www.enfoldsystems.com
  ... ATTENDEE;CN=Sidnei da Silva:mailto:sidnei@enfoldsystems.com
  ... ATTENDEE;CN=Alan Runyan:mailto:alan@enfoldsystems.com
  ... DTSTART:20050525T103000Z
  ... DTEND:20050601T200000Z
  ... STATUS:CONFIRMED
  ... END:VEVENT
  ... END:VCALENDAR
  ... """)

  >>> 'event1' in self.portal.objectIds()
  True

  >>> from Products.Calendaring import EventMarshaller
  >>> marshaller = EventMarshaller()
  >>> print marshaller.marshall(self.portal['event1'])[2]
  BEGIN:VCALENDAR
  PRODID:-//Plone/NONSGML Calendaring//EN
  VERSION:2.0
  BEGIN:VEVENT
  ATTENDEE;CN=Sidnei da Silva:mailto:sidnei@enfoldsystems.com
  ATTENDEE;CN=Alan Runyan:mailto:alan@enfoldsystems.com
  DESCRIPTION:Hosted by Enfold Systems
  DTEND:20050601T200000Z
  DTSTAMP:...
  DTSTART:20050525T103000Z
  LOCATION:New Orleans
  STATUS:CONFIRMED
  SUMMARY:Plone Symposium
  UID:2445300814-1921707519-RID
  URL;VALUE=URI:http://www.enfoldsystems.com
  END:VEVENT
  END:VCALENDAR

Tests for:
[ 1339945 ] Exception when uploading calendar with UID with @ sign
[ 1049703 ] Events with a single quote in their title break the import

  >>> demarshall(CalendarMarshaller, self.portal, r"""
  ... BEGIN:VCALENDAR
  ... PRODID:-//Plone/NONSGML Calendaring//EN
  ... VERSION:2.0
  ... BEGIN:VEVENT
  ... UID:1921707519@localhost
  ... SUMMARY:Master Class: BILLY MARTIN - Clave' and World Rhythms
  ... DESCRIPTION:
  ... LOCATION:New Orleans
  ... DTSTART:20050725T203000Z
  ... DTEND:20050725T220000Z
  ... STATUS:CONFIRMED
  ... END:VEVENT
  ... END:VCALENDAR
  ... """)

  >>> from Products.Calendaring import EventMarshaller
  >>> from Products.Calendaring.marshaller import _generateId
  >>> id = _generateId(uid='1921707519@localhost',
  ...                  title=("Master Class: BILLY MARTIN - Clave' "
  ...                         "and World Rhythms"),
  ...                  context=self.portal)
  >>> marshaller = EventMarshaller()
  >>> print marshaller.marshall(self.portal[id])[2]
  BEGIN:VCALENDAR
  PRODID:-//Plone/NONSGML Calendaring//EN
  VERSION:2.0
  BEGIN:VEVENT
  DESCRIPTION:
  DTEND:20050725T220000Z
  DTSTAMP:...
  DTSTART:20050725T203000Z
  LOCATION:New Orleans
  STATUS:CONFIRMED
  SUMMARY:Master Class: BILLY MARTIN - Clave' and World Rhythms
  UID:1921707519@localhost
  END:VEVENT
  END:VCALENDAR

Tests for iCal 'title' ('X-WR-CALNAME'):
[ 1050190 ] Better handling of spaces in title when publishing from iCal
[ 1048043 ] Subscribing from iCal doesn't get the title of the calendar

  >>> _ = self.portal.invokeFactory('Folder', 'test-calendar')

  >>> self.portal['test-calendar'].Title()
  ''

  >>> demarshall(CalendarMarshaller, self.portal['test-calendar'], r"""
  ... BEGIN:VCALENDAR
  ... PRODID:-//Plone/NONSGML Calendaring//EN
  ... VERSION:2.0
  ... X-WR-CALNAME:Between a Rock 'n a Hard Place
  ... BEGIN:VEVENT
  ... UID:1921707520@localhost
  ... SUMMARY:Master Class: BILLY MARTIN - Clave' and World Rhythms
  ... DESCRIPTION:
  ... LOCATION:New Orleans
  ... DTSTART:20050725T203000Z
  ... DTEND:20050725T220000Z
  ... STATUS:CONFIRMED
  ... END:VEVENT
  ... END:VCALENDAR
  ... """)

  >>> self.portal['test-calendar'].Title()
  "Between a Rock 'n a Hard Place"

  >>> from Products.Calendaring import CalendarMarshaller
  >>> marshaller = CalendarMarshaller()
  >>> print marshaller.marshall(self.portal['test-calendar'])[2]
  BEGIN:VCALENDAR
  PRODID:-//Plone/NONSGML Calendaring//EN
  VERSION:2.0
  X-WR-CALNAME:Between a Rock 'n a Hard Place
  BEGIN:VEVENT
  DESCRIPTION:
  DTEND:20050725T220000Z
  DTSTAMP:...
  DTSTART:20050725T203000Z
  LOCATION:New Orleans
  STATUS:CONFIRMED
  SUMMARY:Master Class: BILLY MARTIN - Clave' and World Rhythms
  UID:1921707520@localhost
  END:VEVENT
  END:VCALENDAR
