Fixed replacing whole document

- json pointer to_last operation returns None for the part in the
  case that it is a whole document pointer
- json patch now checks to see if the part is None and simply returns
  the value to replace the document
- Added a test to verify the fix

1 files changed, 3 insertions, 0 deletions

diff --git a/jsonpatch.py b/jsonpatch.py
index e115273..5c61a0d 100644
--- a/jsonpatch.py
+++ b/jsonpatch.py
@@ -394,6 +394,9 @@ class ReplaceOperation(PatchOperation):
         value = self.operation["value"]
         subobj, part = self.pointer.to_last(obj)
 
+        if part is None:
+            return value
+
         if isinstance(subobj, list):
             if part > len(subobj) or part < 0:
                 raise JsonPatchConflict("can't replace outside of list")