moviedice/src/__tests__/movies/realtime-cache.test.ts

import { readFileSync } from "fs";
import path from "path";

describe("Realtime movies cache update logic", () => {
  const src = readFileSync(
    path.resolve(__dirname, "../../hooks/use-realtime-movies.ts"),
    "utf-8",
  );

  it("handles INSERT events with duplicate guard", () => {
    expect(src).toContain("INSERT");
    // Verify duplicate check exists across pages to prevent optimistic update collisions
    expect(src).toMatch(/pages\.some.*page.*some.*\.id\s*===\s*newMovie\.id/);
  });

  it("handles UPDATE events with map replacement", () => {
    expect(src).toContain("UPDATE");
    // Verify map-based replacement across pages
    expect(src).toMatch(/pages\.map\(/);
  });

  it("handles DELETE events with filter removal", () => {
    expect(src).toContain("DELETE");
    // Verify filter-based removal across pages
    expect(src).toMatch(/page\.filter\(/);
  });

  it("guards against null old data in setQueryData callbacks", () => {
    // Each callback should handle the case where old cache data is undefined/null
    const setQueryDataBlocks = src.match(/setQueryData.*?\(.*?old.*?\)/gs);
    expect(setQueryDataBlocks).not.toBeNull();
    expect(src).toMatch(/if\s*\(\s*!old\s*\)/);
  });

  it("uses moviesQueryKey helper for consistent key generation", () => {
    expect(src).toMatch(/function\s+moviesQueryKey/);
    // Verify the helper is used in the callback
    expect(src).toMatch(/const\s+key\s*=\s*moviesQueryKey\(/);
  });
});