feat: generate MAME device sets from -listxml

A machine that instantiates a device loads the device's ROMs from <shortname>.zip (src/emu/device.cpp:140-152), and a missing required ROM stops that machine (romload.cpp:529-570, 667-671). The BIOS root scan never sees these sets. mame_hash_scraper --devices --listxml reads them from the -listxml of the release mame.yml pins, refuses another release, and cites each set at the ROM_START block holding its ROMs. The BIOS root merge also wrote refs without the upstream prefix and would have rewritten all 171 of them in mame.yml.

wiki/testing-guide.md

@@ -45,7 +45,7 @@ Every module in `tests/`, by the area it guards.
 | Hardware targets and systems | synthetic + target files | `test_extract_targets`, `test_lakka_targets`, `test_libretro_slugs`, `test_system_ids`, `test_system_selection`, `test_target_names`, `test_target_scrapers`, `test_target_systems`, `test_target_verify` |
 | Installer and downloads | loopback server | `test_check_release`, `test_download`, `test_install`, `test_install_cores`, `test_install_experience`, `test_install_selection` |
 | Truth and native export | synthetic + cached originals | `test_export_counts`, `test_export_native_layer`, `test_export_report`, `test_exporters`, `test_truth_diff`, `test_truth_layout` |
-| Scrapers, upstream and provenance | inline sources, synthetic | `test_check_freshness`, `test_dedup`, `test_fbneo_parser`, `test_find_pinned_revision`, `test_hash_merge`, `test_mame_parser`, `test_mame_ref_audit`, `test_profile_sync`, `test_provenance`, `test_refresh_data_dirs`, `test_refresh_failures`, `test_refresh_stale`, `test_retrodeck_scraper_errors`, `test_romset_recipes`, `test_scraper_contract`, `test_upstream`, `test_upstream_index` |
+| Scrapers, upstream and provenance | inline sources, synthetic | `test_check_freshness`, `test_dedup`, `test_fbneo_parser`, `test_find_pinned_revision`, `test_hash_merge`, `test_mame_devices`, `test_mame_parser`, `test_mame_ref_audit`, `test_profile_sync`, `test_provenance`, `test_refresh_data_dirs`, `test_refresh_failures`, `test_refresh_stale`, `test_retrodeck_scraper_errors`, `test_romset_recipes`, `test_scraper_contract`, `test_upstream`, `test_upstream_index` |
 | Site, docs and repository contracts | rendered pages, sources | `test_contributing_text`, `test_data_dir_refs`, `test_dataclass_defaults`, `test_optional_dependencies`, `test_prose_style`, `test_site_availability`, `test_site_cores`, `test_site_exports`, `test_site_platform_hashes`, `test_site_system_links`, `test_site_validation`, `test_site_write`, `test_validate_pr`, `test_validate_pr_hashes`, `test_workflow_paths` |
 
 ## Test architecture
@@ -99,6 +99,18 @@ sets from driver files. Fixtures are inline C source snippets containing
 - Multi-region ROM blocks
 - Macro expansion and edge cases
 
+**test_mame_devices.** Tests the device ROM sets read from a MAME `-listxml`
+and merged into a profile, on an inline listxml and driver source. Covers:
+
+- Only `isdevice="yes"` sets with a dumped ROM kept, from a plain or zipped listxml
+- The `ROM_START` block cited for a set: found through a ROM macro, a block
+  inside a comment ignored, one dump under two names told apart, the label
+  `device_rom_region` returns, not found and ambiguous
+- Merge: a set added under the generated section in name order, a written
+  entry's contents refreshed with its manual fields kept, BIOS root sets left
+  as written, a second run changing nothing, a new BIOS root placed before the
+  section
+
 **test_fbneo_parser.** Tests the FBNeo C source parser that identifies
 `BDF_BOARDROM` sets. Same inline fixture approach.