TEST(scanner): Extend unit test for new behavior of scan_structure_elements

unittests/test_scanner.py

@@ -61,6 +61,12 @@ def test_scan_structure_elements():
                                    converter_registry)
     assert len(recs) == 4
 
+    # Converter registry is generated automatically from the crawler
+    # definition in scan_structure_elements.
+    recs_without_converter_registry = scan_structure_elements(DictElement(name="", value=data),
+                                                              crawler_definition)
+    assert len(recs) == len(recs_without_converter_registry)
+
 
 def test_provenance_debug_data():
     # TODO rewrite the test to use a smaller example setup