Package org.djunits.util

Class ConstantsTest

java.lang.Object

org.djunits.util.ConstantsTest

public class ConstantsTest
extends Object

Unit tests for Constants. Although it is a constants holder, we can still verify:

• Numerical values are as declared (within appropriate tolerances)
• Dimensionality (SI units) of each constant
• Key identities/relations, e.g., μ0·ε0·c² ≈ 1 and ħ = h / (2π)
• Sign and units of elementary-charge based quantities

Notes on tolerances: Some constants include an uncertainty in the comment; relations like μ0·ε0·c² = 1 are tested with a small tolerance to account for those stated uncertainties. Exact definitions (e.g., c, h, N_A) are still subject to floating-point representation; we therefore use a tiny absolute/relative tolerance. Copyright (c) 2025-2026 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved. See for project information https://djunits.org. The DJUNITS project is distributed under a three-clause BSD-style license.

Author:

Alexander Verbraeck (specifications); Test implementation by Copilot.

Constructor Summary

Constructors

Constructor	Description
ConstantsTest()

Method Summary

Modifier and Type	Method	Description
(package private) void	dimensionlessMathConstants()	Verifies PI, TAU, E, PHI are Dimensionless with Unitless.BASE and correct values.
(package private) void	luminousEfficacyDimensionality()	Verifies luminous efficacy dimensionality after fixing the unit string in Constants to include m^2 in the denominator.
(package private) void	mu0TimesEpsilon0TimesCSquaredIsOne()	Verifies the physical identity μ0 · ε0 · c² ≈ 1 (dimensionless).
(package private) void	siConstantsDimensionalityAndValues()	Verifies dimensionality and representative numeric values for fundamental constants.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

ConstantsTest

public ConstantsTest()

Method Details

dimensionlessMathConstants

@Test
void dimensionlessMathConstants()

Verifies PI, TAU, E, PHI are Dimensionless with Unitless.BASE and correct values.

siConstantsDimensionalityAndValues

@Test
void siConstantsDimensionalityAndValues()

Verifies dimensionality and representative numeric values for fundamental constants.

mu0TimesEpsilon0TimesCSquaredIsOne

@Test
void mu0TimesEpsilon0TimesCSquaredIsOne()

Verifies the physical identity μ0 · ε0 · c² ≈ 1 (dimensionless). Uses a modest tolerance due to stated uncertainties in μ0 and ε0.

luminousEfficacyDimensionality

@Test
void luminousEfficacyDimensionality()

Verifies luminous efficacy dimensionality after fixing the unit string in Constants to include m^2 in the denominator.

Enable this test once you change

  "cdsrs3/kg"  →  "cds3sr/kgm2"