fix: keep a system an on-target core reads

tests/test_target_systems.py

@@ -0,0 +1,71 @@
+"""A target keeps a system whose files an on-target core reads.
+
+Batocera files the Enterprise under enterprise-64-128. ep128emu, the core
+that reads ep128emu/roms/exos21.rom, declares enterprise-64 and
+enterprise-128; only CLK carries the joined id. With a target that has
+ep128emu and not CLK, the system was dropped from the report while the
+builder still shipped its ROMs as ep128emu extras.
+"""
+
+from __future__ import annotations
+
+import sys
+import unittest
+from pathlib import Path
+
+REPO_ROOT = Path(__file__).resolve().parent.parent
+sys.path.insert(0, str(REPO_ROOT / "scripts"))
+
+from common import filter_systems_by_target  # noqa: E402
+
+PROFILES = {
+    "ep128emu_core": {
+        "type": "libretro",
+        "systems": ["enterprise-64", "enterprise-128"],
+        "files": [{"name": "exos21.rom", "path": "ep128emu/roms/exos21.rom"}],
+    },
+    "clk": {
+        "type": "standalone",
+        "systems": ["enterprise-64-128"],
+        "files": [{"name": "exos10.bin", "path": "Enterprise/exos10.bin"}],
+    },
+    "generic": {
+        "type": "libretro",
+        "systems": ["other"],
+        "files": [{"name": "bios.bin", "path": "bios.bin"}],
+    },
+}
+
+
+def systems(*files: str) -> dict:
+    return {"enterprise-64-128": {"files": [
+        {"name": f.rsplit("/", 1)[-1], "destination": f} for f in files
+    ]}}
+
+
+class TargetSystems(unittest.TestCase):
+    def kept(self, declared: dict) -> list[str]:
+        return sorted(filter_systems_by_target(
+            declared, PROFILES, {"ep128emu_core"},
+            platform_cores={"ep128emu_core", "clk"},
+        ))
+
+    def test_a_core_reading_the_system_destination_keeps_it(self):
+        self.assertEqual(self.kept(systems("ep128emu/roms/exos21.rom")), ["enterprise-64-128"])
+
+    def test_without_that_evidence_the_off_target_core_drops_it(self):
+        self.assertEqual(self.kept(systems("Enterprise/exos10.bin")), [])
+
+    def test_a_bare_name_is_no_evidence(self):
+        declared = {"enterprise-64-128": {"files": [{"name": "bios.bin"}]}}
+        self.assertEqual(
+            sorted(filter_systems_by_target(
+                declared, PROFILES, {"generic"},
+                platform_cores={"generic", "clk"},
+            )),
+            [],
+        )
+
+
+if __name__ == "__main__":
+    unittest.main()