flow/.agents/skills/frontend-testing/assets/hook-test.template.ts

/**
 * Test template for custom React hooks in Flow.
 *
 * Usage:
 * 1. Copy this file to `__tests__/use-hook-name.test.ts`
 * 2. Replace all TEMPLATE_* placeholders with actual values
 * 3. Remove unused sections
 * 4. Run: npm test -- path/to/__tests__/use-hook-name.test.ts
 */

import { act, renderHook, waitFor } from "@testing-library/react";
// Replace with actual hook import path
import { TEMPLATE_HOOK } from "../TEMPLATE_HOOK";

// ============================================================
// Mocks
// ============================================================

// Mock dependencies (if the hook calls APIs, reads stores, etc.)
// jest.mock("@/controllers/API/api", () => ({
//   __esModule: true,
//   default: {
//     get: jest.fn(),
//     post: jest.fn(),
//   },
// }));

// Mock Zustand store (if the hook reads from a store)
// import useMyStore from "@/stores/myStore";
// beforeEach(() => {
//   useMyStore.setState({ items: [], loading: false });
// });

// ============================================================
// Tests
// ============================================================

describe("TEMPLATE_HOOK", () => {
  beforeEach(() => {
    jest.clearAllMocks();
  });

  // ----------------------------------------------------------
  // Initial State
  // ----------------------------------------------------------

  describe("initial state", () => {
    it("should return the correct initial value", () => {
      const { result } = renderHook(() => TEMPLATE_HOOK());

      // Replace with actual initial state assertions
      // expect(result.current.value).toBe(initialValue);
      // expect(result.current.loading).toBe(false);
      // expect(result.current.error).toBeNull();
    });
  });

  // ----------------------------------------------------------
  // State Updates
  // ----------------------------------------------------------

  describe("state updates", () => {
    it("should update state when action is called", () => {
      const { result } = renderHook(() => TEMPLATE_HOOK());

      act(() => {
        // Call the hook's update function
        // result.current.setValue("new value");
      });

      // Assert the new state
      // expect(result.current.value).toBe("new value");
    });

    it("should handle multiple sequential updates", () => {
      const { result } = renderHook(() => TEMPLATE_HOOK());

      act(() => {
        // result.current.increment();
        // result.current.increment();
        // result.current.increment();
      });

      // expect(result.current.count).toBe(3);
    });
  });

  // ----------------------------------------------------------
  // Parameters
  // ----------------------------------------------------------

  describe("parameters", () => {
    it("should accept and use initial parameters", () => {
      const { result } = renderHook(() =>
        TEMPLATE_HOOK(/* initial params */),
      );

      // Assert hook uses the provided parameters
    });

    it("should react to parameter changes on rerender", () => {
      const { result, rerender } = renderHook(
        ({ param }) => TEMPLATE_HOOK(param),
        { initialProps: { param: "initial" } },
      );

      // Assert initial state
      // expect(result.current.value).toBe("initial");

      // Rerender with new parameter
      rerender({ param: "updated" });

      // Assert updated state
      // expect(result.current.value).toBe("updated");
    });
  });

  // ----------------------------------------------------------
  // Async Behavior
  // ----------------------------------------------------------

  // describe("async behavior", () => {
  //   it("should fetch data on mount", async () => {
  //     jest.mocked(api.get).mockResolvedValueOnce({
  //       data: { items: [{ id: "1" }] },
  //     });
  //
  //     const { result } = renderHook(() => TEMPLATE_HOOK());
  //
  //     // Initially loading
  //     expect(result.current.loading).toBe(true);
  //
  //     // Wait for data
  //     await waitFor(() => {
  //       expect(result.current.loading).toBe(false);
  //     });
  //
  //     expect(result.current.data).toEqual([{ id: "1" }]);
  //   });
  //
  //   it("should handle fetch errors", async () => {
  //     jest.mocked(api.get).mockRejectedValueOnce(new Error("Failed"));
  //
  //     const { result } = renderHook(() => TEMPLATE_HOOK());
  //
  //     await waitFor(() => {
  //       expect(result.current.error).toBeTruthy();
  //     });
  //   });
  // });

  // ----------------------------------------------------------
  // Debounced/Throttled Behavior
  // ----------------------------------------------------------

  // describe("debounced behavior", () => {
  //   beforeEach(() => {
  //     jest.useFakeTimers();
  //   });
  //
  //   afterEach(() => {
  //     jest.runOnlyPendingTimers();
  //     jest.useRealTimers();
  //   });
  //
  //   it("should debounce the callback", () => {
  //     const callback = jest.fn();
  //     const { result } = renderHook(() => TEMPLATE_HOOK(callback, 500));
  //
  //     result.current("arg1");
  //     result.current("arg2");
  //     result.current("arg3");
  //
  //     expect(callback).not.toHaveBeenCalled();
  //
  //     jest.advanceTimersByTime(500);
  //
  //     expect(callback).toHaveBeenCalledTimes(1);
  //     expect(callback).toHaveBeenCalledWith("arg3");
  //   });
  // });

  // ----------------------------------------------------------
  // Memoization
  // ----------------------------------------------------------

  describe("memoization", () => {
    it("should return stable reference when dependencies do not change", () => {
      const { result, rerender } = renderHook(() => TEMPLATE_HOOK());

      const firstResult = result.current;
      rerender();
      const secondResult = result.current;

      // For functions/objects that should be memoized:
      // expect(firstResult.handler).toBe(secondResult.handler);
    });
  });

  // ----------------------------------------------------------
  // Edge Cases
  // ----------------------------------------------------------

  describe("edge cases", () => {
    it("should handle empty input", () => {
      const { result } = renderHook(() => TEMPLATE_HOOK(/* empty/null */));

      // Assert graceful handling
    });

    it("should handle rapid calls", () => {
      const { result } = renderHook(() => TEMPLATE_HOOK());

      act(() => {
        for (let i = 0; i < 100; i++) {
          // result.current.action();
        }
      });

      // Assert correct final state
    });
  });

  // ----------------------------------------------------------
  // Cleanup
  // ----------------------------------------------------------

  // describe("cleanup", () => {
  //   it("should clean up resources on unmount", () => {
  //     const removeListenerSpy = jest.fn();
  //     jest.spyOn(window, "addEventListener").mockImplementation(() => {});
  //     jest.spyOn(window, "removeEventListener").mockImplementation(removeListenerSpy);
  //
  //     const { unmount } = renderHook(() => TEMPLATE_HOOK());
  //     unmount();
  //
  //     expect(removeListenerSpy).toHaveBeenCalled();
  //   });
  // });
});