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Maurice
62b13a278e
The coverage ratchet caught something worth keeping: an inline `(a, b) => (a < b ? -1 : a > b ? 1 : 0)` is a new function with four branches at every call site, and two of the three in src/nest/common sit on error paths that a passing test never walks. Three restatements of the default sort order were enough to pull the domain under its pinned thresholds (functions 97.8% against 99, branches 87.92% against 89). Writing tests to walk those error paths would have been solving the wrong problem. byCodeUnit says the same thing once, is covered once, and the callers read better for it. Its test asserts equality with a bare `.sort()` rather than hand-written expectations, since "identical to the default order" is the whole contract. It also pins what byCodeUnit is NOT: `['Zelt', 'Übernachtung']` keeps that order, where localeCompare swaps it — so the next person reaching for a comparator on a list a human reads picks the other one.
44 lines
1.7 KiB
TypeScript
44 lines
1.7 KiB
TypeScript
/**
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* byCodeUnit restates what a bare `.sort()` already did, so the contract is
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* "identical to the default order" — and that is what these check, against the
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* default rather than against hand-written expectations.
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*/
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import { describe, it, expect } from 'vitest';
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import { byCodeUnit } from '../../../src/nest/common/compare';
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describe('byCodeUnit', () => {
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it('CMP-001: reports less, greater and equal', () => {
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expect(byCodeUnit('a', 'b')).toBe(-1);
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expect(byCodeUnit('b', 'a')).toBe(1);
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expect(byCodeUnit('a', 'a')).toBe(0);
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});
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it('CMP-002: orders ISO dates chronologically, which is why the callers can use it', () => {
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expect(['2026-03-01', '2026-01-15', '2026-02-28'].sort(byCodeUnit))
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.toEqual(['2026-01-15', '2026-02-28', '2026-03-01']);
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});
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it('CMP-003: reproduces the default sort exactly for the ASCII the callers pass', () => {
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const samples = [
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['EUR', 'usd', 'CHF', 'JPY'],
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['b', 'A', 'a', 'B', ''],
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['plugin:one', 'plugin:One', 'plugin:1', 'plugin:'],
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['2026-01-01', '2026-1-1', '2026-01-1'],
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['x'],
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[],
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];
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for (const sample of samples) {
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expect([...sample].sort(byCodeUnit)).toEqual([...sample].sort());
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}
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});
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it('CMP-004: is NOT locale-aware — the reason the doc comment warns callers off names', () => {
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// Code-unit order files every accented word behind the whole ASCII range.
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// A list a person reads wants localeCompare instead; this asserts the
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// difference so nobody reaches for byCodeUnit there by accident.
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expect(['Zelt', 'Übernachtung'].sort(byCodeUnit)).toEqual(['Zelt', 'Übernachtung']);
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expect(['Zelt', 'Übernachtung'].sort((a, b) => a.localeCompare(b, 'de')))
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.toEqual(['Übernachtung', 'Zelt']);
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});
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});
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