COLLECTION Fixed: iterator_up and insert_into_current

During a review of the previous patch the two issues
were found:
a) The col_iterator_up function was not implemented properly
so it got reworked. New implementation changes
the way error condition is handled. Comments were updated accordingly.
b) There was a mising check for validity of the argument in
the col_insert_into_current function. Check was added.
c) Unit test modified to reflect the change in functionality.

1 files changed, 4 insertions, 2 deletions

diff --git a/collection/collection.h b/collection/collection.h
index 7de17d2..5483c13 100644
--- a/collection/collection.h
+++ b/collection/collection.h
@@ -544,9 +544,11 @@ int col_iterate_collection(struct collection_iterator *iterator,
  * collection 'level' levels up.
  * The 'Level' parameter indicates how many levels up you want to jump.
  * If 0 - call is a no op.
- * If the depth is less than requested level function will return error EINVAL.
+ * If the depth is less then requested level the iterator will
+ * get to the 0 level and next call to col_iterate_collection
+ * will return NULL item.
  */
-int col_iterate_up(struct collection_iterator *iterator, int level);
+int col_iterate_up(struct collection_iterator *iterator, unsigned level);
 
 /* How deep are we relative to the top level.
  * This function might report depth that might look misleading.