addition of new dashboard

backend/modules/dashboard/cache.test.js

@@ -0,0 +1,46 @@
+import { jest } from "@jest/globals";
+
+// Manual DB mock: getPool() returns a fake client whose query() the test drives.
+const query = jest.fn();
+const release = jest.fn(async () => {});
+jest.unstable_mockModule("../../db/index.js", () => ({ getPool: async () => ({ query, release }) }));
+
+const { getCached } = await import("./cache.js");
+
+beforeEach(() => {
+  query.mockReset();
+  release.mockClear();
+});
+
+describe("getCached", () => {
+  it("returns the cached value on a fresh hit without computing", async () => {
+    query.mockResolvedValueOnce({ rows: [{ data: { v: 1 } }] });
+    const compute = jest.fn(async () => ({ v: 999 }));
+    const out = await getCached(7, "storage", 1000, compute);
+
+    expect(out).toEqual({ v: 1 });
+    expect(compute).not.toHaveBeenCalled();
+    expect(query).toHaveBeenCalledTimes(1); // SELECT only
+    expect(query.mock.calls[0][1]).toEqual([7, "storage", 1000]);
+  });
+
+  it("computes and upserts on a miss", async () => {
+    query.mockResolvedValueOnce({ rows: [] }).mockResolvedValueOnce({ rows: [] }); // SELECT miss, then INSERT
+    const compute = jest.fn(async () => ({ v: 2 }));
+    const out = await getCached(7, "storage", 1000, compute);
+
+    expect(out).toEqual({ v: 2 });
+    expect(compute).toHaveBeenCalledTimes(1);
+    expect(query).toHaveBeenCalledTimes(2); // SELECT then INSERT
+    const [sql, params] = query.mock.calls[1];
+    expect(sql).toContain("ON CONFLICT (user_id, tag) DO UPDATE");
+    expect(params).toEqual([7, "storage", { v: 2 }]);
+  });
+
+  it("does not cache when compute throws", async () => {
+    query.mockResolvedValueOnce({ rows: [] });
+    const compute = jest.fn(async () => { throw new Error("nope"); });
+    await expect(getCached(7, "storage", 1000, compute)).rejects.toThrow("nope");
+    expect(query).toHaveBeenCalledTimes(1); // SELECT only; no INSERT
+  });
+});