refactor(M03): extract terrain quality mesh cache

src/tools/verify_terrain_quality_mesh_cache.gd

@@ -0,0 +1,67 @@
+extends SceneTree
+
+## Scene-free contract, admission and LRU regression for terrain revisit meshes.
+
+const CACHE_SCRIPT := preload("res://src/render/terrain/terrain_quality_mesh_cache.gd")
+const LOADER_PATH := "res://src/scenes/streaming/streaming_world_loader.gd"
+
+
+func _initialize() -> void:
+	var failures: Array[String] = []
+	_verify_cache_contract(failures)
+	_verify_loader_boundary(failures)
+	if not failures.is_empty():
+		for failure in failures:
+			push_error("TERRAIN_QUALITY_MESH_CACHE: %s" % failure)
+		quit(1)
+		return
+	print("TERRAIN_QUALITY_MESH_CACHE PASS contract_cases=15 loader_calls=3")
+	quit(0)
+
+
+func _verify_cache_contract(failures: Array[String]) -> void:
+	var cache: RefCounted = CACHE_SCRIPT.new()
+	var mesh_a := ArrayMesh.new()
+	var mesh_b := ArrayMesh.new()
+	var mesh_c := ArrayMesh.new()
+	_expect_true(not bool(cache.call("store", "", mesh_a, "baked_full", 2)), "empty key rejected", failures)
+	_expect_true(not bool(cache.call("store", "a", null, "baked_full", 2)), "null mesh rejected", failures)
+	for excluded_source in ["control_splat_cache", "splat_cache", "splat"]:
+		_expect_true(not bool(cache.call("store", "a", mesh_a, excluded_source, 2)), "%s rejected" % excluded_source, failures)
+	_expect_true(bool(cache.call("store", "a", mesh_a, "baked_full", 2)), "first store", failures)
+	_expect_true(bool(cache.call("store", "b", mesh_b, "baked_full", 2)), "second store", failures)
+	var restored_a: Dictionary = cache.call("restore", "a")
+	_expect_true(restored_a.get("mesh") == mesh_a, "restore retains mesh reference", failures)
+	_expect_true(String(restored_a.get("source", "")) == "baked_full", "restore retains source", failures)
+	_expect_true(bool(cache.call("store", "c", mesh_c, "baked_full", 2)), "third store", failures)
+	_expect_true((cache.call("restore", "b") as Dictionary).is_empty(), "oldest evicted after touch", failures)
+	_expect_true(not (cache.call("restore", "a") as Dictionary).is_empty(), "touched entry retained", failures)
+	var diagnostics: Dictionary = cache.call("diagnostic_snapshot")
+	_expect_true(int(diagnostics.get("entry_count", 0)) == 2, "bounded count", failures)
+	(diagnostics.get("entries_oldest_to_newest") as Array).clear()
+	_expect_true(int((cache.call("diagnostic_snapshot") as Dictionary).get("entry_count", 0)) == 2, "diagnostics detached", failures)
+	_expect_true(not bool(cache.call("store", "zero", ArrayMesh.new(), "baked_full", -1)), "negative capacity clamps to zero", failures)
+	cache.call("clear")
+	_expect_true(int((cache.call("diagnostic_snapshot") as Dictionary).get("entry_count", -1)) == 0, "clear releases entries", failures)
+
+
+func _verify_loader_boundary(failures: Array[String]) -> void:
+	var source := _read_text(LOADER_PATH, failures)
+	_expect_true(source.contains("TERRAIN_QUALITY_MESH_CACHE_SCRIPT.new()"), "loader composes cache", failures)
+	_expect_true(source.contains('_terrain_quality_mesh_cache.call("restore", tile_key)'), "loader delegates restore", failures)
+	_expect_true(source.contains('_terrain_quality_mesh_cache.call("clear")'), "loader delegates clear", failures)
+	for removed_symbol in ["_terrain_quality_mesh_cache_order", "func _touch_quality_terrain_mesh_cache", "func _trim_quality_terrain_mesh_cache"]:
+		_expect_true(not source.contains(removed_symbol), "loader omits %s" % removed_symbol, failures)
+
+
+func _read_text(path: String, failures: Array[String]) -> String:
+	var file := FileAccess.open(path, FileAccess.READ)
+	if file == null:
+		failures.append("cannot open %s" % path)
+		return ""
+	return file.get_as_text()
+
+
+func _expect_true(actual_value: bool, label: String, failures: Array[String]) -> void:
+	if not actual_value:
+		failures.append("%s expected true" % label)

src/tools/verify_terrain_quality_mesh_cache.gd.uid

@@ -0,0 +1 @@
+uid://khd1ths2b4ya