feat(federation): add evaluateAuthFailure decision function

Pure function deciding whether the next 401/403 from an active peer triggers backoff or a transition to needs_attention. Threshold = 5, corresponding to ~21.5 min of the existing BACKOFF_SCHEDULE_MS.
2026-04-21 20:32:38 +02:00
parent 1df25737b6
commit 617d71ab4b
2 changed files with 63 additions and 0 deletions
@@ -0,0 +1,35 @@
+import { describe, it, expect } from 'vitest';
+import { evaluateAuthFailure, AUTH_FAILURE_THRESHOLD } from './federationAuthFailure.js';
+
+describe('evaluateAuthFailure', () => {
+  it('returns backoff with incremented count for a first failure', () => {
+    const result = evaluateAuthFailure(0);
+    expect(result).toEqual({ kind: 'backoff', newAuthFailures: 1 });
+  });
+
+  it('returns backoff below the threshold', () => {
+    for (let prev = 0; prev < AUTH_FAILURE_THRESHOLD - 1; prev++) {
+      const result = evaluateAuthFailure(prev);
+      expect(result.kind).toBe('backoff');
+      expect(result.newAuthFailures).toBe(prev + 1);
+    }
+  });
+
+  it('returns transition at the threshold', () => {
+    const result = evaluateAuthFailure(AUTH_FAILURE_THRESHOLD - 1);
+    expect(result).toEqual({
+      kind: 'transition_to_needs_attention',
+      newAuthFailures: AUTH_FAILURE_THRESHOLD,
+    });
+  });
+
+  it('returns transition beyond the threshold', () => {
+    const result = evaluateAuthFailure(AUTH_FAILURE_THRESHOLD + 5);
+    expect(result.kind).toBe('transition_to_needs_attention');
+    expect(result.newAuthFailures).toBe(AUTH_FAILURE_THRESHOLD + 6);
+  });
+
+  it('AUTH_FAILURE_THRESHOLD is 5', () => {
+    expect(AUTH_FAILURE_THRESHOLD).toBe(5);
+  });
+});