Tests

Alongside parameters, Oneil provides tests, which allows users to verify that certain properties, requirements, and expectations hold.

The syntax for tests is test: <test-expression>.

test: 1 + 1 == 2

Component A Length: L_A = 5 :cm
Component B Length: L_B = 3 :cm
Max Length: L_max = 10 :cm

test: L_A + L_B <= L_max

A test expression can be any expression that produces a boolean (true or false). For more information, see Booleans and Number operations.

Examples

The point of a test is to encode a requirement you care about: margins, safety limits, or physical feasibility.

Thrust versus gravity

For a vehicle to accelerate upward, thrust must exceed weight.

Dry mass: m_dry = 420 :kg
Propellant mass: m_prop = 180 :kg
Liftoff mass: m = m_dry + m_prop :kg

Sea-level gravity: g = 9.81 :m/s^2
Liftoff thrust: F_thrust = 7500 :N

test: F_thrust > m * g

Stress and material limit

Keep computed stress below the allowable value derived from yield strength and a safety factor:

Yield strength: sigma_y = 250 :MPa
Safety factor: SF = 2

Allowable stress: sigma_allow = sigma_y / SF :MPa
Working stress: sigma_work = 95 :MPa

test: sigma_work < sigma_allow

Operating temperature

Confirm a junction stays inside the part’s rated range. Temperature uses Kelvin as the underlying dimension:

Ambient: T_amb = 260 :K
Self-heating: delta_T = 40 :K
Junction temperature: T_j = T_amb + delta_T :K

Rated maximum junction: T_max = 400 :K

test: T_j <= T_max

Power budget

Check that available electrical power covers peak demand with headroom:

Supply capability: P_supply = 48 :W
Peak load: P_peak = 35 :W
Minimum design margin: P_margin_min = 5 :W

test: P_supply >= P_peak + P_margin_min

String modes and requirements

Tests can combine numeric checks with string equality if the model uses a parameter to indicate the mode:

Array configuration: config = 'series'
Cell count: n_cells = 12
Cells required for target voltage: n_req = 12

test: config == 'series' and n_cells == n_req