feat: P.3.1 reference test-module — lib-core.maps assertions

init.lua

@@ -0,0 +1,37 @@
+-- =====================================================================
+-- lib-core.maps-test — Reference test-module (P.3.1)
+-- Validates lib-core.maps API contracts via engine.test.* assertions.
+-- See: meta/docs/superpowers/specs/2026-05-10-test-module-pattern-design.md
+-- =====================================================================
+local maps = require("lib-core.maps")
+
+function init(ctx)
+    -- Setup
+    local demo_map = maps.load("maps/demo.map.json")
+    maps.set_current(demo_map)
+
+    -- Geometry assertions
+    local size = maps.size()
+    engine.test.equals(size.w, 16, "map width = 16")
+    engine.test.equals(size.h, 16, "map height = 16")
+    engine.test.equals(maps.tile_size(), 32, "tile_size = 32")
+
+    -- Tile lookup + walkability
+    engine.test.equals(maps.tile_at(0, 0).id,  "stone", "tile_at(0,0) is stone")
+    engine.test.equals(maps.tile_at(5, 5).id,  "grass", "tile_at(5,5) is grass")
+    engine.test.assert(not maps.is_walkable(0, 0), "stone border non-walkable")
+    engine.test.assert(maps.is_walkable(5, 5),     "grass interior walkable")
+
+    -- Arity-flex tile_at: 3-arg with nil map_id falls back to current_map (P.2.1)
+    engine.test.equals(maps.tile_at(nil, 5, 5).id, "grass", "tile_at 3-arg nil-fallback")
+
+    -- Out-of-bounds returns nil
+    engine.test.equals(maps.tile_at(-1, 0), nil, "tile_at OOB negative tx returns nil")
+    engine.test.equals(maps.tile_at(0, 16), nil, "tile_at OOB ty=size.h returns nil")
+
+    -- list() returns registered map-id
+    local list = maps.list()
+    engine.test.equals(#list, 1, "maps.list returns 1 registered map")
+
+    engine.exit(engine.test.failures())
+end