wehub-resource-sync
47 lines
1.8 KiB
TypeScript
47 lines
1.8 KiB
TypeScript
import { describe, it, expect } from "vitest";
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import cuid from "cuid";
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import { hashBucket } from "~/utils/computeBucket";
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describe("hashBucket", () => {
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it("returns a stable value in [0, 100) for the same id", () => {
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const a = hashBucket("org_abc");
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const b = hashBucket("org_abc");
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expect(a).toBe(b);
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expect(a).toBeGreaterThanOrEqual(0);
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expect(a).toBeLessThan(100);
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});
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it("is nested: the set enrolled at 1% is a subset of the set at 5%", () => {
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const ids = Array.from({ length: 5000 }, (_, i) => `org_${i}`);
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const at1 = new Set(ids.filter((id) => hashBucket(id) < 1));
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const at5 = ids.filter((id) => hashBucket(id) < 5);
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for (const id of at1) {
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expect(at5).toContain(id);
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}
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});
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it("distributes roughly uniformly", () => {
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const ids = Array.from({ length: 10000 }, (_, i) => `org_${i}`);
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const under10 = ids.filter((id) => hashBucket(id) < 10).length;
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expect(under10).toBeGreaterThan(700);
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expect(under10).toBeLessThan(1300);
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});
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// Org ids are `@default(cuid())` primary keys (e.g. "cjld2cjxh0000qzrmn831i7rn"),
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// not the synthetic sequential ids above. cuids share a "c" prefix + timestamp/counter
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// structure, so verify the hash still spreads *real-shaped* ids evenly across deciles
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// (so a percentage dial maps to ~that fraction of actual orgs, not just of the id space).
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it("distributes cuids evenly across all 10 deciles", () => {
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const ids = Array.from({ length: 20000 }, () => cuid());
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const counts = new Array(10).fill(0);
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for (const id of ids) {
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counts[Math.floor(hashBucket(id) / 10)]++;
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}
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// Expected ~2000 per decile; allow a wide band so it isn't flaky.
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for (const count of counts) {
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expect(count).toBeGreaterThan(1700);
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expect(count).toBeLessThan(2300);
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}
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});
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});
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