Fix issue with orphaning

Orphaning did not work...
Added a test and an assertion for funny folks
trying to have orphan ranges higher than batch size.

CHANGES.rst

@@ -4,7 +4,8 @@ Changelog
 1.0.3 (unreleased)
 ------------------
 
-- Nothing changed yet.
+- Fix issue with orphaning
+  [do3cc]
 
 
 1.0.2 (2014-04-13)

plone/batching/batch.py

@@ -31,6 +31,8 @@ def __init__(self, sequence, size, start=0, end=0, orphan=0, overlap=0,
         overlap   - the number of overlapping elements in each batch
         pagerange - the number of pages to display in the navigation
         """
+        assert orphan < size, "Having an orphan size, higher than batch size" \
+                              " is undefined"
         start += 1
         self._sequence = sequence
         self._size = size
@@ -155,7 +157,7 @@ def lastpage(self):
         """ Last page of batch
         """
         pages = self.sequence_length / self.pagesize
-        if self.sequence_length % self.pagesize:
+        if (self.sequence_length - self.orphan) % self.pagesize:
             pages += 1
         return pages
 

plone/batching/tests.py

@@ -97,6 +97,13 @@ def test_lastpage(self):
         lastbatch = BaseBatch(range(20), 5, start=batch.last)
         self.assertTrue(lastbatch.islastpage)
 
+    def test_lastpage_with_orphans(self):
+        batch = BaseBatch(range(11), 10, orphan=1)
+        self.assertEqual(1, batch.lastpage)
+        batch = BaseBatch(range(109), 10, orphan=9)
+        self.assertEqual(10, batch.lastpage)
+        self.assertRaises(AssertionError, BaseBatch, [], 10, orphan=20)
+
     def test_items_not_on_page(self):
         batch = BaseBatch(range(20), 5, start=5)
         self.assertEqual(batch.items_not_on_page,