Implement production vertical slice foundation

tests/unit/run_vehicle_application_tests.gd

@@ -0,0 +1,79 @@
+extends SceneTree
+
+const VehicleCommand = preload("res://game/application/vehicle/vehicle_command.gd")
+const CameraLookCommand = preload(
+	"res://game/application/vehicle/camera_look_command.gd"
+)
+const PilotUseCase = preload("res://game/application/vehicle/pilot_use_case.gd")
+const VehicleMotionPort = preload(
+	"res://game/application/interfaces/vehicle_motion_port.gd"
+)
+
+const TEST_COUNT := 10
+
+var _failures: Array[String] = []
+
+
+class RecordingMotionPort extends VehicleMotionPort:
+	var commands: Array[VehicleCommand] = []
+
+
+	func apply_command(command: VehicleCommand) -> void:
+		commands.append(command)
+
+
+func _init() -> void:
+	_test_vehicle_command_contract()
+	_test_camera_command_contract()
+	_test_pilot_use_case_orders_commands()
+
+	if _failures.is_empty():
+		print("Vehicle application unit tests: %d passed, 0 failed." % TEST_COUNT)
+		quit(0)
+	else:
+		for failure: String in _failures:
+			push_error(failure)
+		print("Vehicle application unit tests: %d failed." % _failures.size())
+		quit(1)
+
+
+func _test_vehicle_command_contract() -> void:
+	var neutral: VehicleCommand = VehicleCommand.neutral(0)
+	_expect(neutral.validation_error().is_empty(), "neutral command is valid")
+	_expect(
+		VehicleCommand.new(-1, 0.0, 0.0, 0.0, false).validation_error()
+		== "vehicle command sequence is negative",
+		"negative sequence is rejected"
+	)
+	_expect(
+		not VehicleCommand.new(0, 1.01, 0.0, 0.0, false).validation_error().is_empty(),
+		"non-normalized axis is rejected"
+	)
+
+
+func _test_camera_command_contract() -> void:
+	_expect(CameraLookCommand.new(0.2, -0.1).validation_error().is_empty(), "finite camera look is valid")
+	_expect(
+		not CameraLookCommand.new(NAN, 0.0).validation_error().is_empty(),
+		"non-finite camera look is rejected"
+	)
+
+
+func _test_pilot_use_case_orders_commands() -> void:
+	var port := RecordingMotionPort.new()
+	var pilot := PilotUseCase.new(port)
+	var first = pilot.execute(VehicleCommand.new(0, 1.0, 0.0, 0.0, false))
+	_expect(first.accepted, "first consecutive vehicle command is accepted")
+	_expect(port.commands.size() == 1 and port.commands[0].longitudinal == 1.0, "accepted command reaches motion port")
+
+	var skipped = pilot.execute(VehicleCommand.neutral(2))
+	_expect(not skipped.accepted, "skipped vehicle sequence is rejected")
+	_expect(port.commands.size() == 1, "rejected command does not reach motion port")
+
+	var retry = pilot.execute(VehicleCommand.neutral(1))
+	_expect(retry.accepted and port.commands.size() == 2, "expected sequence remains retryable")
+
+
+func _expect(condition: bool, label: String) -> void:
+	if not condition:
+		_failures.append(label)