fix: dedupe inbound messages across providers

src/infra/dedupe.test.ts

@@ -0,0 +1,34 @@
+import { describe, expect, it } from "vitest";
+
+import { createDedupeCache } from "./dedupe.js";
+
+describe("createDedupeCache", () => {
+  it("marks duplicates within TTL", () => {
+    const cache = createDedupeCache({ ttlMs: 1000, maxSize: 10 });
+    expect(cache.check("a", 100)).toBe(false);
+    expect(cache.check("a", 500)).toBe(true);
+  });
+
+  it("expires entries after TTL", () => {
+    const cache = createDedupeCache({ ttlMs: 1000, maxSize: 10 });
+    expect(cache.check("a", 100)).toBe(false);
+    expect(cache.check("a", 1501)).toBe(false);
+  });
+
+  it("evicts oldest entries when over max size", () => {
+    const cache = createDedupeCache({ ttlMs: 10_000, maxSize: 2 });
+    expect(cache.check("a", 100)).toBe(false);
+    expect(cache.check("b", 200)).toBe(false);
+    expect(cache.check("c", 300)).toBe(false);
+    expect(cache.check("a", 400)).toBe(false);
+  });
+
+  it("prunes expired entries even when refreshed keys are older in insertion order", () => {
+    const cache = createDedupeCache({ ttlMs: 100, maxSize: 10 });
+    expect(cache.check("a", 0)).toBe(false);
+    expect(cache.check("b", 50)).toBe(false);
+    expect(cache.check("a", 120)).toBe(false);
+    expect(cache.check("c", 200)).toBe(false);
+    expect(cache.size()).toBe(2);
+  });
+});