Ensure set vars work fine with set|filter

tests/test_core_tags.py

@@ -457,6 +457,20 @@ def test_block_filtered(self, env_trim):
         assert tmpl.render() == '2'
         assert tmpl.module.foo == u'2'
 
+    def test_block_filtered_set(self, env_trim):
+        def _myfilter(val, arg):
+            assert arg == ' xxx '
+            return val
+        env_trim.filters['myfilter'] = _myfilter
+        tmpl = env_trim.from_string(
+            '{% set a = " xxx " %}'
+            '{% set foo | myfilter(a) | trim | length | string %}'
+            ' {% set b = " yy " %} 42 {{ a }}{{ b }}   '
+            '{% endset %}'
+            '{{ foo }}')
+        assert tmpl.render() == '11'
+        assert tmpl.module.foo == u'11'
+
 
 @pytest.mark.core_tags
 @pytest.mark.with_