Refactor: Extract root components architecture with comprehensive tests

src/RootComponents/Root.test.tsx

@@ -0,0 +1,107 @@
+import "@testing-library/jest-dom";
+import { render, screen } from "@testing-library/react";
+import React from "react";
+import Root from "./Root";
+
+jest.mock("../Explorer/ErrorBoundary", () => ({
+  ErrorBoundary: ({ children }: { children: React.ReactNode }) => (
+    <div data-testid="mock-error-boundary">{children}</div>
+  ),
+}));
+
+jest.mock("@fluentui/react-components", () => ({
+  FluentProvider: ({ children, theme }: { children: React.ReactNode; theme: { colorNeutralBackground1: string } }) => (
+    <div
+      data-testid="mock-fluent-provider"
+      data-theme={theme.colorNeutralBackground1 === "dark" ? "webDarkTheme" : "webLightTheme"}
+    >
+      {children}
+    </div>
+  ),
+  webLightTheme: { colorNeutralBackground1: "light" },
+  webDarkTheme: { colorNeutralBackground1: "dark" },
+}));
+
+jest.mock("./App", () => ({
+  __esModule: true,
+  default: () => <div data-testid="mock-app">App</div>,
+}));
+
+const createMockStore = (isDarkMode: boolean = false) => ({
+  getState: jest.fn(() => ({ isDarkMode })),
+  subscribe: jest.fn(() => jest.fn()),
+});
+
+const mockThemeStore = createMockStore(false);
+
+jest.mock("../hooks/useTheme", () => ({
+  get useThemeStore() {
+    return mockThemeStore;
+  },
+}));
+
+describe("Root", () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+  });
+
+  test("should render Root component with all child components", () => {
+    render(<Root />);
+
+    expect(screen.getByTestId("mock-error-boundary")).toBeInTheDocument();
+    expect(screen.getByTestId("mock-fluent-provider")).toBeInTheDocument();
+    expect(screen.getByTestId("mock-app")).toBeInTheDocument();
+  });
+
+  test("should have correct component hierarchy", () => {
+    render(<Root />);
+
+    const errorBoundary = screen.getByTestId("mock-error-boundary");
+    const fluentProvider = screen.getByTestId("mock-fluent-provider");
+    const app = screen.getByTestId("mock-app");
+
+    expect(errorBoundary).toContainElement(fluentProvider);
+    expect(fluentProvider).toContainElement(app);
+  });
+
+  test("should subscribe to theme changes on mount", () => {
+    render(<Root />);
+
+    expect(mockThemeStore.subscribe).toHaveBeenCalled();
+    expect(mockThemeStore.subscribe).toHaveBeenCalledWith(expect.any(Function));
+  });
+
+  test("should get initial theme state", () => {
+    render(<Root />);
+
+    expect(mockThemeStore.getState).toHaveBeenCalled();
+  });
+
+  test("should handle component unmounting", () => {
+    const mockUnsubscribe = jest.fn();
+    mockThemeStore.subscribe.mockReturnValue(mockUnsubscribe);
+
+    const { unmount } = render(<Root />);
+
+    unmount();
+
+    expect(mockUnsubscribe).toHaveBeenCalled();
+  });
+
+  test("should call getState to initialize theme", () => {
+    render(<Root />);
+
+    expect(mockThemeStore.getState).toHaveBeenCalledTimes(1);
+  });
+
+  test("should handle theme subscription properly", () => {
+    render(<Root />);
+
+    expect(mockThemeStore.subscribe).toHaveBeenCalledTimes(1);
+    expect(mockThemeStore.getState).toHaveBeenCalled();
+  });
+
+  test("should render without errors", () => {
+    expect(() => render(<Root />)).not.toThrow();
+  });
+});