ensure we only use one entity modification method

Author: douglowe

tests/shared.py

@@ -104,6 +104,8 @@ def do_entity_test(
     """
     Shared function to test a RO-Crate entity
     """
+    assert sum([bool(rocrate_entity_patch), bool(rocrate_entity_mod_sparql)]) != 2, "Cannot use rocrate_entity_patch and rocrate_entity_mod_sparql together"
+
     # declare variables
     failed_requirements = None
     detected_issues = None