Fixed tests to work with future icalendar.

There ``;VALUE=DATE-TIME`` is not included because it is already the default.
See collective/icalendar#450

news/450.bugfix

@@ -0,0 +1,2 @@
+Fixed tests to work with future icalendar, where ``;VALUE=DATE-TIME`` is not included because it is already the default.
+[maurits]

plone/app/event/tests/test_icalendar.py

@@ -31,6 +31,11 @@ def traverser(self, context, request):
     def checkOrder(self, text, *order):
         for item in order:
             position = text.find(item)
+            if position == -1:
+                # ;VALUE=DATE-TIME is the default so it is optional.
+                # icalendar will remove it in a future release.
+                # See https://github.com/collective/icalendar/pull/450
+                position = text.find(item.replace(";VALUE=DATE-TIME", ""))
             self.assertTrue(
                 position >= 0, 'menu item "%s" missing or out of order' % item
             )