chore: import upstream snapshot with attribution

tests/unit/memory-cache.test.ts

@@ -0,0 +1,95 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+
+const { memoryCache } = await import("../../src/lib/memory/cache.ts");
+
+const originalDateNow = Date.now;
+const originalMaxSize = memoryCache.maxSize;
+
+test.beforeEach(async () => {
+  await memoryCache.clear();
+  memoryCache.maxSize = originalMaxSize;
+  Date.now = originalDateNow;
+});
+
+test.after(async () => {
+  Date.now = originalDateNow;
+  memoryCache.maxSize = originalMaxSize;
+  await memoryCache.clear();
+});
+
+test("memoryCache tracks cache hits and misses and clear resets stats", async () => {
+  await memoryCache.set("user:1", { value: 1 });
+
+  assert.deepEqual(await memoryCache.get("user:1"), { value: 1 });
+  assert.equal(await memoryCache.get("missing"), null);
+  assert.deepEqual(memoryCache.stats(), {
+    size: 1,
+    maxSize: originalMaxSize,
+    hits: 1,
+    misses: 1,
+  });
+
+  await memoryCache.clear();
+  assert.deepEqual(memoryCache.stats(), {
+    size: 0,
+    maxSize: originalMaxSize,
+    hits: 0,
+    misses: 0,
+  });
+});
+
+test("memoryCache expires entries after their TTL elapses", async () => {
+  let now = 1_000;
+  Date.now = () => now;
+
+  await memoryCache.set("ttl:key", "value", 50);
+  assert.equal(await memoryCache.get("ttl:key"), "value");
+
+  now = 1_060;
+  assert.equal(await memoryCache.get("ttl:key"), null);
+  assert.deepEqual(memoryCache.stats(), {
+    size: 0,
+    maxSize: originalMaxSize,
+    hits: 1,
+    misses: 1,
+  });
+});
+
+test("memoryCache evicts the least recently used entry when full", async () => {
+  memoryCache.maxSize = 2;
+
+  await memoryCache.set("a", "value-a");
+  await memoryCache.set("b", "value-b");
+  assert.equal(await memoryCache.get("a"), "value-a");
+
+  await memoryCache.set("c", "value-c");
+
+  assert.equal(await memoryCache.get("a"), "value-a");
+  assert.equal(await memoryCache.get("b"), null);
+  assert.equal(await memoryCache.get("c"), "value-c");
+  assert.deepEqual(memoryCache.stats(), {
+    size: 2,
+    maxSize: 2,
+    hits: 3,
+    misses: 1,
+  });
+});
+
+test("memoryCache invalidates entries by regex pattern", async () => {
+  await memoryCache.set("session:1", "a");
+  await memoryCache.set("session:2", "b");
+  await memoryCache.set("profile:1", "c");
+
+  await memoryCache.invalidate("^session:");
+
+  assert.equal(await memoryCache.get("session:1"), null);
+  assert.equal(await memoryCache.get("session:2"), null);
+  assert.equal(await memoryCache.get("profile:1"), "c");
+  assert.deepEqual(memoryCache.stats(), {
+    size: 1,
+    maxSize: originalMaxSize,
+    hits: 1,
+    misses: 2,
+  });
+});