- Do not override my_bp$mo / my_bp$ab in tests: assigning plain character
strips the <mo>/<ab> class, which check_reference_data() rejects. Use the
mo/ab values already present in the source row instead.
- Use NA_character_ instead of NA for my_bp$host so the host column keeps
its character class.
- Pass breakpoint_type = "animal" explicitly in the host-fallback test since
the custom reference_data only contains animal-type breakpoints.
https://claude.ai/code/session_01Q8KtFFGG9qrjAgLJBbxG2U
7277534d40