[QA] Fuel System Test Plan (GUT)

[ikostan]

Fuel System Test Plan (GDUnit4)

This test plan validates the Fuel System behavior across core logic, edge cases, signals, persistence, and UI integration.

Scope Definition

• Unit Tests: Fuel calculations, clamping, scaling (no scene tree)
• Integration Tests: Interaction with Globals.gd, signal emission
• UI Tests: Reactive updates only (no logic validation)

All time-based behavior must use deterministic delta simulation (no real-time dependency).

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Test Name	Objective	Setup / Method	Expected Result
test_fuel_initialization	Verify fuel initializes to max capacity	Instantiate resource with config values	fuel == max_capacity
test_fuel_consumption_static_exact	Validate deterministic fuel consumption	Apply fixed delta over N steps using constant rate	fuel == start - (rate * total_time) (within tolerance)
test_fuel_consumption_with_scaling	Verify increased consumption during acceleration	Simulate normal vs "speed_up" states with same delta	Accelerated consumption > base consumption
test_fuel_not_negative	Ensure fuel is clamped at zero	Simulate consumption beyond depletion	fuel == 0.0 (never negative)
test_fuel_exact_zero_transition	Validate correct behavior at exact zero boundary	Reduce fuel to exactly 0.0	No float drift; value equals 0.0
test_fuel_depletion_signal_emitted_once	Ensure signal fires exactly once on depletion	Observe signal while crossing from >0 → 0	fuel_depleted emitted once only
test_multiple_depletion_signal_not_emitted_twice	Prevent repeated signal spam	Continue consumption after depletion	No additional signals after first emission
test_refuel_basic	Verify refuel increases fuel correctly	Apply refuel amount within capacity	fuel == previous + amount
test_refuel_clamped_to_max	Ensure refuel does not exceed capacity	Refuel beyond max capacity	fuel == max_capacity
test_refuel_negative_input	Validate handling of invalid refuel input	Call refuel(-X)	Value unchanged OR safely clamped
test_persistence_valid_config	Ensure config values are loaded correctly	Load from valid user://settings.cfg	Runtime values match config
test_persistence_missing_keys_fallback	Verify fallback behavior for missing config fields	Load config with missing keys	Defaults applied for missing values
test_persistence_invalid_types_fallback	Ensure robustness against invalid config data	Load config with wrong types	Invalid values ignored; defaults used
test_ui_updates_on_fuel_change_signal	Validate UI reacts to fuel updates	Bind UI element to fuel change signal	UI reflects updated fuel value

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Notes

• Use assert_almost_eq(..., tolerance) for float comparisons
• Avoid frame/time dependency; simulate with explicit delta
• Signals must be tested using observers/spies
• UI tests should validate binding, not internal logic
• Persistence tests should isolate filesystem (mock or temp config)

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