Gas bombers consume gas from the fleet hold when firing (#60)

Shots cost GAS_PER_SHOT (5) from GameState.fleet_inventory, not the
bank - the fleet has to be carrying its own ammunition. The button's
enabled rule now also requires affordability, and a press on a ready-
but-unaffordable bomber still consumes the touch to explain itself via
a new status label (GasBombStatus, IconButton's own "greyed but still
pressable" convention) rather than either silently doing nothing or
consuming the bomber's cooldown for a shot that never fires.

Also documents a real, reproducible GDScript trap hit while writing
tests/test_gas_bomber_ammo.gd: a bare `ClassName.SOME_CONST` reference
anywhere in a -s entry test script can corrupt method resolution for
the WHOLE script, making an unrelated, earlier `some_node._process()`
call fail with "Nonexistent function '_process' in base 'Nil'" despite
the node being valid and the method existing (confirmed via
has_method()). Root cause unconfirmed; fixed by mirroring the constant
's value into a local const instead of referencing the class directly,
in all three gas-bomber tests.

tests/test_gas_bomber.gd and test_gas_bomber_cooldowns.gd updated to
stock fleet gas first, since shots are no longer free.

tests/test_gas_bomber.gd

@@ -3,7 +3,10 @@ extends SceneTree
 var game_state: Node
 var main: Node
 var fleet: Node
-var skill: GasBombController
+var skill: Node
+# Mirrors GasBombController.AOE_RADIUS's value rather than referencing the
+# class constant directly - see test_gas_bomber_cooldowns.gd's identical fix.
+const AOE_RADIUS_FOR_TEST: float = 180.0
 var inside_enemies: Array = []
 var outside_enemy: Node
 var stage := 0
@@ -24,6 +27,9 @@ func _initialize() -> void:
 	game_state.fleet_cargo = 0
 	game_state.fleet_gas_cargo = 0
 	game_state.build_time_scale = 0.01
+	# #60: after research/crafting resets the fleet hold below, top it up
+	# with fleet-carried gas for the shot itself (ammunition, not the ore/gas
+	# spent researching or crafting the bomber).
 
 	# Research is gas-only: any amount of ore and 29 gas must still leave it
 	# waiting, then the thirtieth unit starts and completes the unlock.
@@ -69,6 +75,7 @@ func _initialize() -> void:
 		_fail_now("crafting did not produce a typed Gas Bomber")
 		return
 
+	game_state.fleet_gas_cargo = 20
 	main = load("res://Main.tscn").instantiate()
 	root.add_child(main)
 	fleet = main.get_node("Fleet")
@@ -117,7 +124,7 @@ func _process(delta: float) -> bool:
 				enemy.speed = 0.0
 				inside_enemies.append(enemy)
 			outside_enemy = load("res://Enemy.tscn").instantiate()
-			outside_enemy.position = skill.aim_target + Vector2(GasBombController.AOE_RADIUS + 80.0, 0)
+			outside_enemy.position = skill.aim_target + Vector2(AOE_RADIUS_FOR_TEST + 80.0, 0)
 			main.add_child(outside_enemy)
 			outside_enemy.speed = 0.0
 

tests/test_gas_bomber_ammo.gd

@@ -0,0 +1,142 @@
+extends SceneTree
+
+# Headless gameplay test: run with
+#   godot --headless -s res://tests/test_gas_bomber_ammo.gd
+# Forgejo #60: gas bomb shots draw ammunition from the FLEET HOLD
+# (GameState.fleet_inventory), not the bank - the fleet has to be carrying
+# its own gas.
+#
+# Covers:
+#   A. gas sitting in the bank does not enable firing - only the fleet
+#      hold counts
+#   B. with insufficient fleet gas the button is disabled, pressing it
+#      explains why, and no projectile is created / no cooldown consumed
+#   C. firing drains exactly GAS_PER_SHOT from the fleet hold and nothing
+#      from the bank
+
+var game_state: Node
+var main: Node
+var fleet: Node
+var skill: Node
+var bomber_component: Node
+var stage: int = 0
+var elapsed: float = 0.0
+
+# Mirrors GasBombController.GAS_PER_SHOT's value rather than referencing
+# the class constant directly - a bare ClassName.CONST reference elsewhere
+# in a test
+# script has been observed to corrupt method resolution for the WHOLE
+# script (an unrelated skill._process() call earlier in the same file then
+# fails with "Nonexistent function '_process' in base 'Nil'"), root cause
+# unconfirmed. See tests/test_gas_bomber_cooldowns.gd's identical fix.
+const GAS_PER_SHOT: int = 5
+
+
+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.vessel_levels["unlock_gas_bomber"] = 1
+	game_state.rocks = 0
+	game_state.gas = 0
+	game_state.fleet_gas_cargo = 0
+	main = load("res://Main.tscn").instantiate()
+	root.add_child(main)
+	fleet = main.get_node("Fleet")
+	skill = main.get_node("GasBombController")
+
+
+func _process(delta: float) -> bool:
+	elapsed += delta
+	match stage:
+		0:
+			if elapsed < 0.2:
+				return false
+			main.get_node("EnemySpawner").set_process(false)
+			main.get_node("AsteroidField").set_process(false)
+			# An interceptor rides along purely for its "cargo" capability
+			# (#56): a fleet made only of a gas bomber has zero cargo
+			# capacity, which would silently clamp every fleet_gas_cargo
+			# assignment below to 0.
+			fleet.spawn_ships(2, Vector2.ZERO, PackedStringArray([
+				GameState.VESSEL_INTERCEPTOR, GameState.VESSEL_GAS_BOMBER]))
+			bomber_component = fleet.ships[1].get_component("gas_bomber")
+			skill._process(0.0)
+
+			# --- A. bank gas does not count -----------------------------------
+			game_state.gas = 500
+			game_state.fleet_gas_cargo = 0
+			skill._process(0.0)
+			if skill.button.enabled:
+				return _fail_now("500 banked gas (0 in the fleet hold) left the control enabled")
+			print("500 banked gas, 0 fleet gas: control correctly disabled")
+
+			# --- B. insufficient fleet gas --------------------------------------
+			game_state.fleet_gas_cargo = GAS_PER_SHOT - 1
+			skill._process(0.0)
+			if skill.button.enabled:
+				return _fail_now("fleet gas one short of GAS_PER_SHOT left the control enabled")
+
+			var press := InputEventScreenTouch.new()
+			press.index = 3
+			press.position = skill.button.global_position + skill.button.size * 0.5
+			press.pressed = true
+			main._handle_touch(press)
+			if skill.aiming:
+				return _fail_now("aiming began despite insufficient fleet gas")
+			if skill.status.text == "":
+				return _fail_now("an unaffordable press did not explain itself")
+			print("insufficient fleet gas: disabled, press explains itself, no aiming began")
+			if not bomber_component.is_ready():
+				return _fail_now("a refused press consumed the bomber's cooldown")
+			if game_state.fleet_resource(GameState.RESOURCE_GAS) != GAS_PER_SHOT - 1:
+				return _fail_now("a refused press spent fleet gas anyway")
+			print("no cooldown consumed, no gas spent on a refused press")
+
+			# --- C. exact ammo cost on a real shot ------------------------------
+			game_state.fleet_gas_cargo = GAS_PER_SHOT + 7
+			skill._process(0.0)
+			if not skill.button.enabled:
+				return _fail_now("enough fleet gas still left the control disabled")
+
+			var press2 := InputEventScreenTouch.new()
+			press2.index = 4
+			press2.position = skill.button.global_position + skill.button.size * 0.5
+			press2.pressed = true
+			main._handle_touch(press2)
+			if not skill.aiming:
+				return _fail_now("an affordable press did not begin aiming")
+			var drag := InputEventScreenDrag.new()
+			drag.index = 4
+			drag.position = press2.position + Vector2(-300.0, 0.0)
+			main._handle_drag(drag)
+			var release := InputEventScreenTouch.new()
+			release.index = 4
+			release.position = drag.position
+			release.pressed = false
+			main._handle_touch(release)
+
+			if skill.projectiles.size() != 1:
+				return _fail_now("a paid-for shot did not launch a projectile")
+			if bomber_component.is_ready():
+				return _fail_now("firing did not consume the bomber's cooldown")
+			if game_state.fleet_resource(GameState.RESOURCE_GAS) != 7:
+				return _fail_now("fleet gas after firing is %d, expected 7 (paid exactly %d)" \
+					% [game_state.fleet_resource(GameState.RESOURCE_GAS), GAS_PER_SHOT])
+			if game_state.gas != 500:
+				return _fail_now("firing touched the bank (%d), expected it untouched at 500" % game_state.gas)
+			print("firing drained exactly %d from the fleet hold, bank untouched" % GAS_PER_SHOT)
+
+			print("TEST_GAS_BOMBER_AMMO: PASS")
+			quit(0)
+			return true
+	return false
+
+
+func _fail_now(message: String) -> bool:
+	print("TEST_GAS_BOMBER_AMMO: FAIL (%s)" % message)
+	quit(1)
+	return true

tests/test_gas_bomber_cooldowns.gd

@@ -2,7 +2,7 @@ extends SceneTree
 
 var main: Node
 var fleet: Node
-var skill: GasBombController
+var skill: Node
 var elapsed := 0.0
 
 
@@ -12,6 +12,8 @@ func _initialize() -> void:
 	state.extractors.clear()
 	state.transporters.clear()
 	state.vessel_levels["unlock_gas_bomber"] = 1
+	# #60: shots draw from the fleet hold now - stock enough for both fires.
+	state.fleet_gas_cargo = 20
 	main = load("res://Main.tscn").instantiate()
 	root.add_child(main)
 	fleet = main.get_node("Fleet")
@@ -53,7 +55,7 @@ func _process(delta: float) -> bool:
 
 	# Rearming one bomber restores one available shot without touching the
 	# other bomber's cooldown.
-	first.tick(GasBombController.COOLDOWN)
+	first.tick(5.0)  # matches GasBombController.COOLDOWN
 	skill._process(0.0)
 	if not first.is_ready() or second.is_ready() or not skill.button.enabled:
 		return _fail("one completed cooldown did not restore exactly one shot")

tests/test_gas_bomber_cooldowns.gd.uid

@@ -1 +0,0 @@
-uid://cwo6ake5taias