feat: Add event-based automation triggers (#2537)

tests/utils/exponential-backoff.test.ts

@@ -0,0 +1,98 @@
+import { afterEach, describe, expect, it, vi } from 'vitest';
+import { ExponentialBackoff } from '../../src/utils/exponential-backoff';
+
+describe('ExponentialBackoff', () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it('should start at attempts=0', () => {
+    const backoff = new ExponentialBackoff({ baseSeconds: 1, maxSeconds: 60 });
+    expect(backoff.getAttempts()).toBe(0);
+  });
+
+  it('should compute exponential delays with the configured base', () => {
+    // Pin jitter to 1.0 so we can read the raw exponential values.
+    vi.spyOn(Math, 'random').mockReturnValue(1);
+    const backoff = new ExponentialBackoff({
+      baseSeconds: 1,
+      maxSeconds: 60,
+      jitterMin: 1,
+      jitterMax: 1,
+    });
+
+    expect(backoff.next()).toBe(1);
+    expect(backoff.next()).toBe(2);
+    expect(backoff.next()).toBe(4);
+    expect(backoff.next()).toBe(8);
+    expect(backoff.next()).toBe(16);
+  });
+
+  it('should cap delays at maxSeconds', () => {
+    vi.spyOn(Math, 'random').mockReturnValue(1);
+    const backoff = new ExponentialBackoff({
+      baseSeconds: 1,
+      maxSeconds: 10,
+      jitterMin: 1,
+      jitterMax: 1,
+    });
+
+    backoff.next();
+    backoff.next();
+    backoff.next();
+    backoff.next();
+
+    expect(backoff.next()).toBe(10);
+    expect(backoff.next()).toBe(10);
+  });
+
+  it('should apply jitter within the configured range', () => {
+    // Math.random() returns 0; jitter = jitterMin.
+    vi.spyOn(Math, 'random').mockReturnValue(0);
+    const backoff = new ExponentialBackoff({
+      baseSeconds: 10,
+      maxSeconds: 100,
+      jitterMin: 0.5,
+      jitterMax: 1.0,
+    });
+
+    expect(backoff.next()).toBe(5);
+  });
+
+  it('should increment the attempt counter on each next()', () => {
+    const backoff = new ExponentialBackoff({ baseSeconds: 1, maxSeconds: 60 });
+
+    expect(backoff.getAttempts()).toBe(0);
+    backoff.next();
+    expect(backoff.getAttempts()).toBe(1);
+    backoff.next();
+    expect(backoff.getAttempts()).toBe(2);
+  });
+
+  it('should reset the attempt counter and start over', () => {
+    vi.spyOn(Math, 'random').mockReturnValue(1);
+    const backoff = new ExponentialBackoff({
+      baseSeconds: 1,
+      maxSeconds: 60,
+      jitterMin: 1,
+      jitterMax: 1,
+    });
+
+    backoff.next();
+    backoff.next();
+    backoff.next();
+    expect(backoff.getAttempts()).toBe(3);
+
+    backoff.reset();
+    expect(backoff.getAttempts()).toBe(0);
+    expect(backoff.next()).toBe(1);
+  });
+
+  it('should default jitter to [0.5, 1.0] when not provided', () => {
+    vi.spyOn(Math, 'random').mockReturnValue(0);
+    const backoff = new ExponentialBackoff({ baseSeconds: 4, maxSeconds: 100 });
+
+    // jitter = 0.5 + 0 * (1.0 - 0.5) = 0.5; delay = 4 * 0.5 = 2.
+    expect(backoff.next()).toBe(2);
+  });
+});