Fixed item update to delete free tags

When the form is submitted, any existing free tags will be deleted
before the ones present in the form are added.

django/website/hid/tests/add_edit_item_view_tests.py

@@ -741,6 +741,22 @@ def test_free_tags_created_on_item_update(view, form):
     assert 'free-tags' in taxonomies
 
 
+@pytest.mark.django_db
+def test_existing_tag_deleted_on_item_update(view, form):
+    transport.items.add_free_terms(view.item['id'], 'free-tags', ['age 35-40'])
+
+    form.cleaned_data['terms[free-tags]'] = 'Monrovia'
+
+    view.form_valid(form)
+    assert_no_messages(view.request, messages.ERROR)
+
+    item = transport.items.get(view.item['id'])
+
+    terms = [t['name'] for t in item['terms']]
+    assert 'Monrovia' in terms
+    assert 'age 35-40' not in terms
+
+
 @pytest.mark.django_db
 def test_free_tags_created_for_new_item(add_view, form):
     form.cleaned_data['terms[free-tags]'] = 'Monrovia|Important|age 35-40'

django/website/hid/views/item.py

@@ -252,6 +252,7 @@ class AddEditItemView(FormView):
 
     def _add_free_terms(self, item_id, free_terms):
         for (taxonomy, value) in free_terms.iteritems():
+            transport.items.delete_all_terms(item_id, taxonomy)
             terms = value.split('|')
             transport.items.add_free_terms(item_id, taxonomy, terms)