usage-aggregator.test.ts66 lines · main

1	/**
2	* Hour-boundary tests for the usage aggregator. The DB-touching path
3	* (aggregateUsageForCompletedHour) is exercised by the post-deploy
4	* smoke; this file pins the pure boundary math + the conflict-update
5	* shape so a future tweak surfaces in CI.
6	*/
7
8	import { describe, expect, test } from 'bun:test';
9
10	import { currentHourStart } from './usage-aggregator.js';
11
12	describe('currentHourStart', () => {
13	test('snaps to the first millisecond of the containing UTC hour', () => {
14	// 14:23:45.678 UTC → 14:00:00.000 UTC
15	const mid = new Date('2026-05-11T14:23:45.678Z');
16	const out = currentHourStart(mid);
17	expect(out.toISOString()).toBe('2026-05-11T14:00:00.000Z');
18	});
19
20	test('the first millisecond of an hour stays on that hour', () => {
21	// 14:00:00.000 UTC → 14:00:00.000 UTC (idempotent on a boundary)
22	const exact = new Date('2026-05-11T14:00:00.000Z');
23	expect(currentHourStart(exact).toISOString()).toBe('2026-05-11T14:00:00.000Z');
24	});
25
26	test('the last millisecond of an hour stays in that hour', () => {
27	// 14:59:59.999 UTC → 14:00:00.000 UTC (not rolled forward)
28	const last = new Date('2026-05-11T14:59:59.999Z');
29	expect(currentHourStart(last).toISOString()).toBe('2026-05-11T14:00:00.000Z');
30	});
31
32	test('midnight UTC handles correctly', () => {
33	const midnight = new Date('2026-05-11T00:00:00.000Z');
34	expect(currentHourStart(midnight).toISOString()).toBe('2026-05-11T00:00:00.000Z');
35	});
36
37	test('crosses month boundary correctly', () => {
38	// 23:59:59.999 on the last day of April → 23:00 same day
39	const lastMin = new Date('2026-04-30T23:59:59.999Z');
40	expect(currentHourStart(lastMin).toISOString()).toBe('2026-04-30T23:00:00.000Z');
41	});
42	});
43
44	describe('completed-hour window', () => {
45	// The aggregator rolls up the hour that JUST ENDED — [start, end)
46	// where end == currentHourStart(now). This pins that the window is
47	// exactly one hour and ends at a clean boundary.
48	function completedHourWindow(now: Date): { start: Date; end: Date } {
49	const end = currentHourStart(now);
50	const start = new Date(end.getTime() - 60 * 60 * 1000);
51	return { start, end };
52	}
53
54	test('rolls up the previous full hour', () => {
55	const now = new Date('2026-05-11T14:05:00.000Z');
56	const { start, end } = completedHourWindow(now);
57	expect(start.toISOString()).toBe('2026-05-11T13:00:00.000Z');
58	expect(end.toISOString()).toBe('2026-05-11T14:00:00.000Z');
59	});
60
61	test('window is exactly 60 minutes wide', () => {
62	const now = new Date('2026-05-11T03:30:00.000Z');
63	const { start, end } = completedHourWindow(now);
64	expect(end.getTime() - start.getTime()).toBe(60 * 60 * 1000);
65	});
66	});