Add carrier vessel (#57)

An unarmed hauler with no weapon component - only VesselCargoComponent,
so it structurally cannot fire, the same pattern that already made the
shield vessel weaponless after #35. Its cargo_capacity (120, six
interceptors' worth) makes it the first real payoff for #56's fleet
hold cap.

Wired into the crafter, hangar and ship lab menus, all of which were
already generic over VesselDefinitions.fleet()/.all() - only the
per-vessel UI *nodes* are hand-placed (Main.tscn), not the logic, so
this repacks those three button rows to 4/4/5 columns and extends
BuildController's matching onready arrays. No new signal handlers were
needed.

Also fixes test_vessel_composition.gd's hardcoded fleet-catalog size
(3 -> 4) now that a fourth vessel is fleet-eligible.

tests/_carrier_crafter_preview.gd

@@ -0,0 +1,17 @@
+extends Node2D
+
+# Preview, not a test - #57's crafter menu screenshot with all 4 fleet
+# vessels researched, carrier included as the new 4th entry.
+#
+#   bash tests/screenshot.sh res://tests/_carrier_crafter_preview.tscn /tmp/crafter.png 20 720x1280
+
+
+func _ready() -> void:
+	GameState.buildings.clear()
+	GameState.extractors.clear()
+	GameState.rocks = 500
+	GameState.vessel_levels = {"unlock_shield": 1, "unlock_gas_bomber": 1, "unlock_carrier": 1}
+	var main: Node = load("res://Main.tscn").instantiate()
+	add_child(main)
+	main.get_node("UI/CraftMenu").visible = true
+	main.get_node("BuildController")._refresh_craft_status()

tests/_carrier_crafter_preview.tscn

@@ -0,0 +1,6 @@
+[gd_scene load_steps=2 format=3]
+
+[ext_resource type="Script" path="res://tests/_carrier_crafter_preview.gd" id="1"]
+
+[node name="CarrierCrafterPreview" type="Node2D"]
+script = ExtResource("1")

tests/_carrier_hangar_preview.gd

@@ -0,0 +1,21 @@
+extends Node2D
+
+# Preview, not a test - #57's hangar menu screenshot with all 4 fleet
+# vessels researched, one of each stored, and a carrier crewed into the
+# fleet so both rows show the new entry.
+#
+#   bash tests/screenshot.sh res://tests/_carrier_hangar_preview.tscn /tmp/hangar.png 20 720x1280
+
+
+func _ready() -> void:
+	GameState.buildings.clear()
+	GameState.extractors.clear()
+	GameState.rocks = 500
+	GameState.vessel_levels = {"unlock_shield": 1, "unlock_gas_bomber": 1, "unlock_carrier": 1}
+	GameState.stored_vessels = ["shield", "gas_bomber", "carrier"]
+	var main: Node = load("res://Main.tscn").instantiate()
+	add_child(main)
+	var fleet: Node = main.get_node("Fleet")
+	fleet.spawn_ships(2, Vector2.ZERO, PackedStringArray(["interceptor", "carrier"]))
+	main.get_node("UI/HangarMenu").visible = true
+	main.get_node("BuildController")._refresh_hangar()

tests/_carrier_hangar_preview.tscn

@@ -0,0 +1,6 @@
+[gd_scene load_steps=2 format=3]
+
+[ext_resource type="Script" path="res://tests/_carrier_hangar_preview.gd" id="1"]
+
+[node name="CarrierHangarPreview" type="Node2D"]
+script = ExtResource("1")

tests/test_carrier_vessel.gd

@@ -0,0 +1,239 @@
+extends SceneTree
+
+# Headless gameplay test: run with
+#   godot --headless -s res://tests/test_carrier_vessel.gd
+# Forgejo #57: an unarmed hauler that substantially raises how much the
+# fleet can carry (#56).
+#
+# Covers:
+#   A. crewing a carrier raises GameState.fleet_cargo_capacity() by its stat
+#   B. a carrier never fires - no weapon component, no projectile ever
+#      originates from it even with an enemy parked in interceptor fire range
+#   C. it is unbuildable until researched
+#   D. it appears in the crafter, hangar and ship lab with correct name,
+#      cost, icon and colour, and is buildable once researched
+
+var game_state: Node
+var scene: Node
+var fleet: Node
+var controller: Node
+var field: Node
+var crafter_id: int = 0
+var mothership_id: int = 0
+var definition: Resource
+var capacity_before: int = 0
+var enemy: Node
+var stage: int = 0
+var elapsed: float = 0.0
+
+const MOTHERSHIP_AT: Vector2 = Vector2(0.0, 0.0)
+const CRAFTER_AT: Vector2 = Vector2(3000.0, 0.0)
+# Same slot the crafter/hangar UI arrays give carrier: VesselDefinitions.ORDER
+# appends carrier after transporter, and VesselDefinitions.fleet() filters
+# transporter out, so carrier lands last among the 4 fleet-eligible vessels
+# (interceptor, shield, gas_bomber, carrier) in both craft_vessel_* and the
+# hangar_* arrays.
+const FLEET_UI_INDEX: int = 3
+# The ship lab shows every vessel including the transporter, so carrier is
+# the 5th and last slot there.
+const LAB_UI_INDEX: int = 4
+
+
+func _initialize() -> void:
+	game_state = root.get_node("GameState")
+	game_state.buildings.clear()
+	game_state.extractors.clear()
+	game_state.transporters.clear()
+	game_state.stored_vessels.clear()
+	game_state.reset_progression()
+	game_state.build_time_scale = 0.02
+	game_state.rocks = 500
+	scene = load("res://Main.tscn").instantiate()
+	root.add_child(scene)
+	fleet = scene.get_node("Fleet")
+	controller = scene.get_node("BuildController")
+
+
+func _clear_hazards() -> void:
+	for a in get_nodes_in_group("asteroids"):
+		if is_instance_valid(a):
+			a.queue_free()
+	for e in get_nodes_in_group("enemies"):
+		if is_instance_valid(e):
+			e.queue_free()
+
+
+func _process(delta: float) -> bool:
+	elapsed += delta
+	match stage:
+		0:
+			if elapsed < 0.2:
+				return false
+			scene.get_node("AsteroidField").set_process(false)
+			scene.get_node("EnemySpawner").set_process(false)
+			_clear_hazards()
+
+			# --- structural: unarmed, cargo-capable, fleet-eligible ---------
+			definition = game_state.vessel_definition(GameState.VESSEL_CARRIER)
+			if definition == null or not definition.fleet_eligible:
+				return _fail("carrier is not a fleet-eligible vessel definition")
+			if definition.capabilities.has("weapon"):
+				return _fail("carrier declares a weapon capability")
+			if not definition.capabilities.has("cargo"):
+				return _fail("carrier does not declare the cargo capability")
+
+			# --- A. capacity math, directly -----------------------------------
+			if game_state.fleet_cargo_capacity(PackedStringArray(["carrier"])) != 120:
+				return _fail("one carrier's capacity contribution is %d, expected 120" \
+					% game_state.fleet_cargo_capacity(PackedStringArray(["carrier"])))
+			print("structural: unarmed, cargo capability, contributes 120 alone")
+
+			# --- C. gated until researched --------------------------------
+			field = scene.get_node("BuildingField")
+			field.place(GameState.BUILDING_MOTHERSHIP, MOTHERSHIP_AT)
+			mothership_id = int(game_state.buildings[-1].id)
+			field.place(GameState.BUILDING_SHIP_CRAFTER, CRAFTER_AT)
+			crafter_id = int(game_state.buildings[-1].id)
+			field.place(GameState.BUILDING_SHIP_LAB, CRAFTER_AT + Vector2(0.0, 400.0))
+			if game_state.vessel_is_unlocked(GameState.VESSEL_CARRIER):
+				return _fail("carrier starts unlocked")
+			if game_state.queue_order(crafter_id, GameState.VESSEL_CARRIER):
+				return _fail("queue_order accepted an unresearched carrier")
+			print("unresearched carrier is unbuildable, as expected")
+
+			# --- D. locked state in the crafter UI -------------------------
+			controller.craft_building_id = crafter_id
+			controller._refresh_craft_status()
+			if controller.craft_vessel_buttons[FLEET_UI_INDEX].enabled:
+				return _fail("a locked carrier shows enabled in the crafter menu")
+
+			stage = 1
+			elapsed = 0.0
+			return false
+		1:
+			if elapsed < 0.1:
+				return false
+			# --- C continued: unlocking ------------------------------------
+			if not game_state.unlock_vessel(GameState.VESSEL_CARRIER):
+				return _fail("unlock_vessel(carrier) failed with 500 ore in the bank")
+			if not game_state.vessel_is_unlocked(GameState.VESSEL_CARRIER):
+				return _fail("carrier still reports locked after unlocking")
+			if game_state.product_costs(GameState.VESSEL_CARRIER) != {GameState.RESOURCE_ORE: 24}:
+				return _fail("carrier's build cost is %s, expected 24 ore" \
+					% game_state.product_costs(GameState.VESSEL_CARRIER))
+			print("researched: unlocked, costs %s" % game_state.product_costs(GameState.VESSEL_CARRIER))
+
+			# --- D. unlocked state in the crafter UI ------------------------
+			controller._refresh_craft_status()
+			var craft_button: IconButton = controller.craft_vessel_buttons[FLEET_UI_INDEX]
+			var craft_label: Label = controller.craft_vessel_labels[FLEET_UI_INDEX]
+			if not craft_button.enabled:
+				return _fail("an unlocked carrier still shows disabled in the crafter menu")
+			if craft_button.icon != definition.icon or craft_button.glow_color != definition.glow_color:
+				return _fail("crafter carrier button does not match its definition's icon/colour")
+			if not craft_label.text.begins_with(definition.display_name):
+				return _fail("crafter carrier label reads '%s', expected to start with '%s'" \
+					% [craft_label.text, definition.display_name])
+			if not game_state.queue_order(crafter_id, GameState.VESSEL_CARRIER):
+				return _fail("queue_order rejected a researched carrier")
+			print("crafter: enabled, correct icon/colour, correct label, buildable")
+
+			# Bypass the build timer/delivery wait - that queue mechanism is
+			# generic and already covered for every other vessel
+			# (test_building_stock_queue.gd, test_resources_and_buildings.gd
+			# etc.); this ticket is about the carrier's OWN behaviour, not
+			# re-proving crafting works.
+			game_state.stored_vessels.append(GameState.VESSEL_CARRIER)
+
+			# --- D. hangar display -------------------------------------------
+			controller._refresh_hangar()
+			var available_slot: IconButton = controller.hangar_available_slots[FLEET_UI_INDEX]
+			var available_label: Label = controller.hangar_available_labels[FLEET_UI_INDEX]
+			if available_slot.icon != definition.icon or available_slot.glow_color != definition.glow_color:
+				return _fail("hangar carrier slot does not match its definition's icon/colour")
+			var expected_available: String = "%s\n1 available" % definition.display_name
+			if available_label.text != expected_available:
+				return _fail("hangar carrier label reads '%s', expected '%s'" \
+					% [available_label.text, expected_available])
+			print("hangar: correct icon/colour, shows 1 available")
+
+			# --- A continued: crewing it raises capacity ---------------------
+			# The default fleet (5 interceptors) already sits at
+			# max_fleet_size() with reset_progression()'s cleared skills, which
+			# would make _on_hangar_crew_type refuse for being full - shrink
+			# to 1 ship first so there is room to crew the carrier at all.
+			fleet.spawn_ships(1, MOTHERSHIP_AT, PackedStringArray([GameState.VESSEL_INTERCEPTOR]))
+			capacity_before = game_state.fleet_cargo_total_capacity()
+			controller._on_hangar_crew_type(FLEET_UI_INDEX)
+			if not fleet.has_vessel_type(GameState.VESSEL_CARRIER):
+				return _fail("crewing from the hangar did not add a carrier to the fleet")
+			var capacity_after: int = game_state.fleet_cargo_total_capacity()
+			if capacity_after != capacity_before + 120:
+				return _fail("crewing a carrier moved capacity %d -> %d, expected +120" \
+					% [capacity_before, capacity_after])
+			print("crewed: capacity %d -> %d (+120)" % [capacity_before, capacity_after])
+
+			# --- D. ship lab display -------------------------------------------
+			controller.lab_vessel = GameState.VESSEL_CARRIER
+			controller._refresh_lab()
+			var lab_button: IconButton = controller.lab_vessel_buttons[LAB_UI_INDEX]
+			var lab_label: Label = controller.lab_vessel_labels[LAB_UI_INDEX]
+			if lab_button.icon != definition.icon or lab_button.glow_color != definition.glow_color:
+				return _fail("ship lab carrier slot does not match its definition's icon/colour")
+			if lab_label.text != definition.display_name:
+				return _fail("ship lab carrier label reads '%s', expected '%s'" \
+					% [lab_label.text, definition.display_name])
+			print("ship lab: correct icon/colour/label")
+
+			stage = 2
+			elapsed = 0.0
+			return false
+		2:
+			# --- B. never fires, even with a target in range -----------------
+			# Isolate: JUST a carrier in the fleet, nothing else nearby that
+			# could fire instead and make the check meaningless.
+			fleet.spawn_ships(1, Vector2.ZERO, PackedStringArray([GameState.VESSEL_CARRIER]))
+			stage = 3
+			elapsed = 0.0
+			return false
+		3:
+			# A settling tick before the enemy appears: queue_free() on the
+			# ships spawn_ships() just replaced does not remove them from the
+			# tree instantly, so a stale interceptor's weapon could otherwise
+			# still get one last physics tick against a target added in the
+			# same frame - a false positive, not the carrier firing.
+			if elapsed < 0.3:
+				return false
+			var enemy_scene: PackedScene = load("res://Enemy.tscn")
+			enemy = enemy_scene.instantiate()
+			enemy.position = fleet.get_centroid() + Vector2(220.0, 0.0)
+			scene.add_child(enemy)
+			# Frozen in place: a chaser closes distance and kills on contact,
+			# and an unarmed carrier has nothing to stop that. Letting it
+			# approach would wipe the fleet, trip the "rebuild at the
+			# mothership" safety net (a default INTERCEPTOR), and that
+			# interceptor firing would look like a carrier-firing false
+			# positive - this test is about whether the carrier fires, not
+			# whether it can survive unescorted.
+			enemy.set_physics_process(false)
+			stage = 4
+			elapsed = 0.0
+			return false
+		4:
+			if elapsed < 2.0:
+				return false
+			var projectiles: Array = get_nodes_in_group("player_projectiles")
+			if not projectiles.is_empty():
+				return _fail("%d projectile(s) originated from a fleet made only of a carrier" \
+					% projectiles.size())
+			print("no projectiles after %.1fs with an enemy in interceptor fire range" % elapsed)
+			print("TEST_CARRIER_VESSEL: PASS")
+			quit(0)
+			return true
+	return false
+
+
+func _fail(message: String) -> bool:
+	print("TEST_CARRIER_VESSEL: FAIL (%s)" % message)
+	quit(1)
+	return true

tests/test_vessel_composition.gd

@@ -23,7 +23,7 @@ func _process(delta: float) -> bool:
 		return false
 	var definitions: Array = VESSEL_DEFINITIONS.all()
 	var fleet_definitions: Array = VESSEL_DEFINITIONS.fleet()
-	if fleet_definitions.size() != 3 \
+	if fleet_definitions.size() != 4 \
 			or fleet_definitions.any(func(definition): return definition.has_capability("transport")):
 		return _fail("logistics transporters leaked into the combat-fleet catalog")
 	if ships.size() != definitions.size():