Complete the central rule set

Worked example

A repeat-input test might press a one-time choice rapidly. The accepted event happens once, while later calls observe the changed state and do nothing. Scaffold C-PUZZLE — A testable gate rule Setup: Create Node root GateLab and attach this script. The pure gate_open function does not read input or change a scene. A level can call it with its inventory and lever state. Assertions run on start. For the assignment write additional tests before changing the rule. ```gdscript extends Node func gate_open(has_key: bool, lever_on: bool, alarm_on: bool) -> bool: return has_key and lever_on and not alarm_on func _ready() -> void: assert(gate_open(true, true, false)) assert(not gate_open(false, true, false)) assert(not gate_open(true, false, false)) assert(not gate_open(true, true, true)) print("Gate checks passed") ``` Scaffold C-INVENTORY — Dictionary inventory with guarded spending Setup: Attach to Node InventoryLab for standalone testing. In a real level put the same functions on its inventory node and update UI after successful calls. Item IDs are short fixed strings, never a player’s name. A key represents one item type and its integer value is the quantity. ```gdscript extends Node var items: Dictionary = {"seed": 0, "water": 0} func add_item(id: String, amount: int = 1) -> bool: if not items.has(id) or amount <= 0: return false items[id] = int(items[id]) + amount return true func spend(id: String, amount: int = 1) -> bool: if not items.has(id) or amount <= 0 or int(items[id]) < amount: return false items[id] = int(items[id]) - amount return true func _ready() -> void: assert(add_item("seed", 2)) assert(spend("seed", 1)) assert(not spend("seed", 2)) assert(items["seed"] == 1) ``` Scaffold C-TESTS — A tiny pure-function test harness Setup: Attach to Node TestLab. If using command line, create a separate SceneTree harness rather than running this Node script with --script. Run current TestLab scene in editor; assert reports a failed condition in Debugger. No external test framework or package is needed. ```gdscript extends Node func bounded_score(old_score: int, change: int) -> int: return clampi(old_score + change, 0, 999) func _ready() -> void: assert(bounded_score(10, 2) == 12) assert(bounded_score(0, -3) == 0) assert(bounded_score(998, 9) == 999) print("3 score checks passed") ```

A testable gate rule

GDScript (Godot 4, not Scratch, Python, JavaScript or C#). Scaffold C-PUZZLE. Copy starts from this text. The desk does not run it.

Scene and node setup

Create Node root GateLab and attach this script. The pure gate_open function does not read input or change a scene. A level can call it with its inventory and lever state. Assertions run on start. For the assignment write additional tests before changing the rule.

extends Node
func gate_open(has_key: bool, lever_on: bool, alarm_on: bool) -> bool:
    return has_key and lever_on and not alarm_on
func _ready() -> void:
    assert(gate_open(true, true, false))
    assert(not gate_open(false, true, false))
    assert(not gate_open(true, false, false))
    assert(not gate_open(true, true, true))
    print("Gate checks passed")

Checks to run in the editor

• Four supplied assertions pass.
• A complete truth table contains eight input combinations.

Native Godot 4.7.2.stable.official.ed1daf0bf headless compile and representative node-tree/runtime tests passed; see native-qa-results.json. Visual UI, audible output, exports and website submission still need separate checks.

Dictionary inventory with guarded spending

GDScript (Godot 4, not Scratch, Python, JavaScript or C#). Scaffold C-INVENTORY. Copy starts from this text. The desk does not run it.

Scene and node setup

Attach to Node InventoryLab for standalone testing. In a real level put the same functions on its inventory node and update UI after successful calls. Item IDs are short fixed strings, never a player’s name. A key represents one item type and its integer value is the quantity.

extends Node
var items: Dictionary = {"seed": 0, "water": 0}
func add_item(id: String, amount: int = 1) -> bool:
    if not items.has(id) or amount <= 0:
        return false
    items[id] = int(items[id]) + amount
    return true
func spend(id: String, amount: int = 1) -> bool:
    if not items.has(id) or amount <= 0 or int(items[id]) < amount:
        return false
    items[id] = int(items[id]) - amount
    return true
func _ready() -> void:
    assert(add_item("seed", 2))
    assert(spend("seed", 1))
    assert(not spend("seed", 2))
    assert(items["seed"] == 1)

Checks to run in the editor

• Spending more than owned returns false and does not change inventory.
• Unknown IDs and nonpositive amounts are rejected.

Native Godot 4.7.2.stable.official.ed1daf0bf headless compile and representative node-tree/runtime tests passed; see native-qa-results.json. Visual UI, audible output, exports and website submission still need separate checks.

A tiny pure-function test harness

GDScript (Godot 4, not Scratch, Python, JavaScript or C#). Scaffold C-TESTS. Copy starts from this text. The desk does not run it.

Scene and node setup

Attach to Node TestLab. If using command line, create a separate SceneTree harness rather than running this Node script with --script. Run current TestLab scene in editor; assert reports a failed condition in Debugger. No external test framework or package is needed.

extends Node
func bounded_score(old_score: int, change: int) -> int:
    return clampi(old_score + change, 0, 999)
func _ready() -> void:
    assert(bounded_score(10, 2) == 12)
    assert(bounded_score(0, -3) == 0)
    assert(bounded_score(998, 9) == 999)
    print("3 score checks passed")

Checks to run in the editor

• All three assertions pass.
• Intentionally change expected 12 to 13 and observe a failure, then restore.

Native Godot 4.7.2.stable.official.ed1daf0bf headless compile and representative node-tree/runtime tests passed; see native-qa-results.json. Visual UI, audible output, exports and website submission still need separate checks.

Complete the central rule set — evidence task

1. 1. Finish the central rule and add three focused tests.
2. 2. Update the rule-to-code map with actual function names.

Deliverable. Rule-complete checkpoint and rule/code/test map.

Acceptance checks

• VGC-L152-T1. Each required rule has a code location and test.
• VGC-L152-T2. No rule is enforced only by label text or visual button state.

Understanding question. What is the risk of enforcing a rule only in the interface?

Include a downloadable project ZIP with project.godot, .tscn, .gd and original asset files when code changes. A private, teacher-accessible download link to that ZIP is equivalent. Screenshots or a playthrough do not replace editable source.

If this is still shaky. Work on one task-board item at a time and checkpoint after each passing test. Do not expand the room count yet. Start with the first assigned task and re-run its acceptance test before adding the remaining feature.

Optional extra. Add a harmless alternate input or optional route after required mechanics pass. Document one changed parameter, your prediction, and the observed effect; optional, not required for completion.

Turn in typed notes and a JPEG, PNG, or WebP screenshot. One https address is stored as text and is not opened, extracted, or run. An MP3, WAV, M4A, MP4, or WebM file up to 4 MB can show a demo. The demo does not replace editable source. Zip and code files are refused. If there is no private link, keep the project on the family computer and review the code in person.

• Your first 2D game

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