100 lines
2.7 KiB
TypeScript
100 lines
2.7 KiB
TypeScript
import { afterEach, describe, expect, it, vi } from 'vitest';
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import { ExponentialBackoff } from '../../src/utils/exponential-backoff';
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describe('ExponentialBackoff', () => {
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afterEach(() => {
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vi.restoreAllMocks();
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});
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it('should start at attempts=0', () => {
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const backoff = new ExponentialBackoff({ baseSeconds: 1, maxSeconds: 60 });
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expect(backoff.getAttempts()).toBe(0);
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});
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it('should compute exponential delays with the configured base', () => {
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// Pin jitter to 1.0 so we can read the raw exponential values.
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vi.spyOn(Math, 'random').mockReturnValue(1);
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const backoff = new ExponentialBackoff({
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baseSeconds: 1,
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maxSeconds: 60,
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jitterMin: 1,
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jitterMax: 1,
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});
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expect(backoff.next()).toBe(1);
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expect(backoff.next()).toBe(2);
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expect(backoff.next()).toBe(4);
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expect(backoff.next()).toBe(8);
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expect(backoff.next()).toBe(16);
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});
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it('should cap delays at maxSeconds', () => {
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vi.spyOn(Math, 'random').mockReturnValue(1);
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const backoff = new ExponentialBackoff({
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baseSeconds: 1,
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maxSeconds: 10,
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jitterMin: 1,
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jitterMax: 1,
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});
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backoff.next();
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backoff.next();
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backoff.next();
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backoff.next();
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expect(backoff.next()).toBe(10);
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expect(backoff.next()).toBe(10);
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});
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it('should apply jitter within the configured range', () => {
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// Math.random() returns 0; jitter = jitterMin.
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vi.spyOn(Math, 'random').mockReturnValue(0);
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const backoff = new ExponentialBackoff({
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baseSeconds: 10,
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maxSeconds: 100,
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jitterMin: 0.5,
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jitterMax: 1.0,
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});
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expect(backoff.next()).toBe(5);
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});
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it('should increment the attempt counter on each next()', () => {
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const backoff = new ExponentialBackoff({ baseSeconds: 1, maxSeconds: 60 });
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expect(backoff.getAttempts()).toBe(0);
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backoff.next();
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expect(backoff.getAttempts()).toBe(1);
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backoff.next();
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expect(backoff.getAttempts()).toBe(2);
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});
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it('should reset the attempt counter and start over', () => {
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vi.spyOn(Math, 'random').mockReturnValue(1);
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const backoff = new ExponentialBackoff({
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baseSeconds: 1,
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maxSeconds: 60,
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jitterMin: 1,
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jitterMax: 1,
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});
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backoff.next();
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backoff.next();
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backoff.next();
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expect(backoff.getAttempts()).toBe(3);
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backoff.reset();
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expect(backoff.getAttempts()).toBe(0);
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expect(backoff.next()).toBe(1);
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});
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it('should default jitter to [0.5, 1.0] when not provided', () => {
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vi.spyOn(Math, 'random').mockReturnValue(0);
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const backoff = new ExponentialBackoff({ baseSeconds: 4, maxSeconds: 100 });
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// jitter = 0.5 + 0 * (1.0 - 0.5) = 0.5; delay = 4 * 0.5 = 2.
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expect(backoff.next()).toBe(2);
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});
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});
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