/**
 * Example-only file.
 *
 * Not part of the public API surface or published bundle. This sketch shows
 * how to exercise a simple design-token invariant in unit tests using Vitest,
 * which this repo already uses for its own test suite. The pattern is test-
 * runner agnostic; you can adapt it to Jest, Mocha, or any other framework.
 */

import { assertMatchingUnits, m } from '@css-bookends/css-calipers';
import { describe, it } from 'vitest';

// Pretend these spacing tokens come from a design token file or configuration
// layer. The intent is a simple invariant: small <= large and both share units.
const spacingTokens = {
  spaceSm: m(4), // defaults to "px" if no unit is given
  spaceLg: m(12),
};

describe('spacing tokens (example unit test)', () => {
  it('use the same unit for related tokens', () => {
    const { spaceSm, spaceLg } = spacingTokens;

    // Unit consistency between related tokens.
    assertMatchingUnits(
      spaceSm,
      spaceLg,
      'spacing tokens: spaceSm and spaceLg must share units',
    );
  });

  it('keep small <= large', () => {
    const { spaceSm, spaceLg } = spacingTokens;

    // Ordering invariant: small should never exceed large.
    const smValue = spaceSm.getValue();
    const lgValue = spaceLg.getValue();

    if (!(smValue <= lgValue)) {
      throw new Error(
        `spacing tokens out of order: ` +
          `spaceSm=${spaceSm.css()}, spaceLg=${spaceLg.css()}`,
      );
    }
  });
});