CodeRabbit Generated Unit Tests: Add Jest/JSDOM unit tests for book, library, main, indexedDB, style

tests/unit/book.test.js

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+/**
+ * Testing library/framework: Jest (expect/describe/test) with jsdom environment.
+ * These tests validate the public interfaces and DOM interactions for the book module.
+ *
+ * If your project uses Vitest, these tests are largely compatible (minor API tweaks may be needed).
+ */
+
+jest.mock('epubjs', () => {
+  // Mock ePub constructor returning a predictable book object used by loadBook()
+  const mockLocations = {
+    generate: jest.fn(() => Promise.resolve()),
+    length: jest.fn(() => 42),
+    cfiFromLocation: jest.fn((loc) => `epubcfi(/6/${loc})`),
+    locationFromCfi: jest.fn(() => 3),
+  };
+
+  const mockNavigation = {
+    toc: Promise.resolve([{ label: 'Chapter 1', href: 'ch1.xhtml' }]),
+  };
+
+  const mockBook = {
+    ready: Promise.resolve(),
+    renderTo: jest.fn(() => ({
+      display: jest.fn(() => Promise.resolve()),
+      on: jest.fn(),
+      prev: jest.fn(),
+      next: jest.fn(),
+    })),
+    loaded: { metadata: Promise.resolve({ title: 'Test Title' }) },
+    locations: mockLocations,
+    navigation: mockNavigation,
+  };
+
+  const ePub = jest.fn(() => mockBook);
+  ePub.__mock = { mockBook, mockLocations };
+  return { __esModule: true, default: ePub };
+});
+
+jest.mock('../../src/main', () => ({
+  showLoading: jest.fn(),
+  hideLoading: jest.fn(),
+  showError: jest.fn(),
+}));
+jest.mock('../../src/library', () => ({
+  toggleLibrary: jest.fn(),
+}));
+
+/**
+ * Helper to inject required DOM nodes before importing the module under test.
+ */
+function setupDomSkeleton() {
+  document.body.innerHTML = `
+    <button id="toc-button" disabled></button>
+    <button id="prev-button" disabled></button>
+    <button id="next-button" disabled></button>
+    <input id="current-page" value="1" />
+    <div id="overlay"></div>
+    <span id="total-pages"></span>
+    <span id="book-title"></span>
+    <div id="toc-container"></div>
+    <div id="toc-content"></div>
+    <div id="viewer"></div>
+  `;
+}
+
+// FileReader mock to control onload/onerror behavior in openBook()
+class MockFileReader {
+  constructor() {
+    this.onload = null;
+    this.onerror = null;
+  }
+  readAsArrayBuffer(file) {
+    // If test toggled error path, trigger onerror; else trigger onload
+    if (file && file.__causeReadError) {
+      this.onerror && this.onerror({ target: { error: 'boom' } });
+    } else {
+      const buf = new ArrayBuffer(8);
+      this.onload && this.onload({ target: { result: buf } });
+    }
+  }
+}
+
+describe('book module', () => {
+  let bookModule;
+  let ePub;
+  let mainMocks;
+  let libMocks;
+
+  beforeEach(async () => {
+    jest.resetModules();
+    setupDomSkeleton();
+    global.FileReader = MockFileReader;
+
+    // Re-require mocks to access instances
+    ePub = (await import('epubjs')).default;
+    mainMocks = await import('../../src/main');
+    libMocks = await import('../../src/library');
+
+    // Import module under test after DOM/mocks are set
+    bookModule = await import('../../src/book.js');
+  });
+
+  afterEach(() => {
+    jest.clearAllMocks();
+  });
+
+  describe('openBook', () => {
+    test('shows error for non-EPUB file and does not read', () => {
+      const file = new Blob(['not-epub'], { type: 'text/plain' });
+      Object.defineProperty(file, 'name', { value: 'notes.txt' });
+      const evt = { target: { files: [file] } };
+
+      bookModule.openBook(evt);
+
+      expect(mainMocks.showError).toHaveBeenCalledWith('The selected file is not a valid EPUB file.');
+      expect(mainMocks.showLoading).not.toHaveBeenCalled();
+    });
+
+    test('no-op when no file is selected', () => {
+      const evt = { target: { files: [] } };
+      bookModule.openBook(evt);
+      expect(mainMocks.showLoading).not.toHaveBeenCalled();
+      expect(mainMocks.showError).not.toHaveBeenCalled();
+    });
+
+    test('reads EPUB, calls load flow, and hides loading on success', async () => {
+      const file = new Blob([new Uint8Array([1, 2, 3])], { type: 'application/epub+zip' });
+      Object.defineProperty(file, 'name', { value: 'book.epub' });
+      const evt = { target: { files: [file] } };
+
+      bookModule.openBook(evt);
+
+      // showLoading called before reading
+      expect(mainMocks.showLoading).toHaveBeenCalled();
+
+      // Allow microtasks to flush
+      await Promise.resolve();
+      await new Promise(setImmediate);
+
+      // hideLoading called after loadBook resolves
+      expect(mainMocks.hideLoading).toHaveBeenCalled();
+      expect(mainMocks.showError).not.toHaveBeenCalled();
+    });
+
+    test('handles FileReader error path', async () => {
+      const file = new Blob([new Uint8Array([9])], { type: 'application/epub+zip' });
+      Object.defineProperty(file, 'name', { value: 'bad.epub' });
+      // Signal our MockFileReader to emit an error
+      Object.defineProperty(file, '__causeReadError', { value: true });
+      const evt = { target: { files: [file] } };
+
+      bookModule.openBook(evt);
+
+      await Promise.resolve();
+
+      expect(mainMocks.hideLoading).toHaveBeenCalled();
+      expect(mainMocks.showError).toHaveBeenCalledWith(expect.stringContaining('Error reading file:'));
+    });
+  });
+
+  describe('openBookFromEntry', () => {
+    test('closes library, shows loading, loads and hides loading on success', async () => {
+      const fakeFile = new Blob([new Uint8Array([1, 2])], { type: 'application/epub+zip' });
+      fakeFile.arrayBuffer = jest.fn(async () => new ArrayBuffer(4));
+      const entry = { getFile: jest.fn(async () => fakeFile) };
+
+      await bookModule.openBookFromEntry(entry);
+
+      expect(libMocks.toggleLibrary).toHaveBeenCalledWith(false);
+      expect(mainMocks.showLoading).toHaveBeenCalled();
+      expect(entry.getFile).toHaveBeenCalled();
+      expect(fakeFile.arrayBuffer).toHaveBeenCalled();
+      expect(mainMocks.hideLoading).toHaveBeenCalled();
+      expect(libMocks.toggleLibrary).not.toHaveBeenCalledWith(true);
+      expect(mainMocks.showError).not.toHaveBeenCalled();
+    });
+
+    test('reopens library and shows error on failure', async () => {
+      const entry = { getFile: jest.fn(async () => { throw new Error('nope'); }) };
+
+      await bookModule.openBookFromEntry(entry);
+
+      expect(libMocks.toggleLibrary).toHaveBeenCalledWith(false);
+      expect(libMocks.toggleLibrary).toHaveBeenCalledWith(true);
+      expect(mainMocks.showError).toHaveBeenCalledWith(expect.stringContaining('Error opening book:'));
+      expect(mainMocks.hideLoading).toHaveBeenCalled();
+    });
+  });
+
+  describe('navigation controls', () => {
+    test('prevPage and nextPage invoke rendition methods when initialized', async () => {
+      // Trigger a minimal load to set up rendition
+      const file = new Blob([new Uint8Array([1])], { type: 'application/epub+zip' });
+      Object.defineProperty(file, 'name', { value: 'ok.epub' });
+      bookModule.openBook({ target: { files: [file] } });
+      await Promise.resolve();
+      await new Promise(setImmediate);
+
+      const { mockBook } = (await import('epubjs')).default.__mock;
+      const rendition = mockBook.renderTo.mock.results[0].value;
+
+      bookModule.prevPage();
+      bookModule.nextPage();
+
+      expect(rendition.prev).toHaveBeenCalled();
+      expect(rendition.next).toHaveBeenCalled();
+    });
+
+    test('prevPage and nextPage are no-ops without rendition', () => {
+      expect(() => bookModule.prevPage()).not.toThrow();
+      expect(() => bookModule.nextPage()).not.toThrow();
+    });
+  });
+
+  describe('goToPage', () => {
+    test('no-op if no book or no locations', () => {
+      const viewer = document.getElementById('viewer');
+      expect(viewer).toBeTruthy();
+      // Without loading a book, should do nothing
+      expect(() => bookModule.goToPage()).not.toThrow();
+    });
+
+    test('navigates to valid page index and ignores out-of-range/invalid inputs', async () => {
+      // Load book to initialize locations and rendition
+      const file = new Blob([new Uint8Array([1])], { type: 'application/epub+zip' });
+      Object.defineProperty(file, 'name', { value: 'ok.epub' });
+      bookModule.openBook({ target: { files: [file] } });
+      await Promise.resolve();
+      await new Promise(setImmediate);
+
+      const { mockBook } = (await import('epubjs')).default.__mock;
+      const rendition = mockBook.renderTo.mock.results[0].value;
+
+      // Valid page (1-based in input)
+      const input = document.getElementById('current-page');
+      input.value = '4';
+      bookModule.goToPage();
+      expect(mockBook.locations.cfiFromLocation).toHaveBeenCalledWith(3);
+      expect(rendition.display).toHaveBeenCalledWith(expect.stringContaining('epubcfi('));
+
+      // Invalid: non-numeric
+      input.value = 'abc';
+      rendition.display.mockClear();
+      bookModule.goToPage();
+      expect(rendition.display).not.toHaveBeenCalled();
+
+      // Out of range: 0
+      input.value = '0';
+      rendition.display.mockClear();
+      bookModule.goToPage();
+      expect(rendition.display).not.toHaveBeenCalled();
+
+      // Out of range: > length
+      input.value = '999';
+      rendition.display.mockClear();
+      bookModule.goToPage();
+      expect(rendition.display).not.toHaveBeenCalled();
+    });
+  });
+
+  describe('TOC toggles', () => {
+    test('toggleToc toggles open class on container and overlay', () => {
+      const toc = document.getElementById('toc-container');
+      const overlay = document.getElementById('overlay');
+      expect(toc.classList.contains('open')).toBe(false);
+      expect(overlay.classList.contains('open')).toBe(false);
+
+      bookModule.toggleToc();
+
+      expect(toc.classList.contains('open')).toBe(true);
+      expect(overlay.classList.contains('open')).toBe(true);
+
+      bookModule.toggleToc();
+
+      expect(toc.classList.contains('open')).toBe(false);
+      expect(overlay.classList.contains('open')).toBe(false);
+    });
+
+    test('closeToc removes open class', () => {
+      const toc = document.getElementById('toc-container');
+      const overlay = document.getElementById('overlay');
+      toc.classList.add('open');
+      overlay.classList.add('open');
+
+      bookModule.closeToc();
+
+      expect(toc.classList.contains('open')).toBe(false);
+      expect(overlay.classList.contains('open')).toBe(false);
+    });
+  });
+
+  describe('load side-effects', () => {
+    test('enables navigation buttons and sets book title', async () => {
+      const file = new Blob([new Uint8Array([1])], { type: 'application/epub+zip' });
+      Object.defineProperty(file, 'name', { value: 'ok.epub' });
+      bookModule.openBook({ target: { files: [file] } });
+      await Promise.resolve();
+      await new Promise(setImmediate);
+
+      const prev = document.getElementById('prev-button');
+      const next = document.getElementById('next-button');
+      const tocBtn = document.getElementById('toc-button');
+      const title = document.getElementById('book-title');
+      const totalPages = document.getElementById('total-pages');
+
+      expect(prev.disabled).toBe(false);
+      expect(next.disabled).toBe(false);
+      expect(tocBtn.disabled).toBe(false);
+      expect(title.textContent).toBe('Test Title');
+      expect(totalPages.textContent).toBe('42');
+    });
+
+    test('falls back to default titles on metadata errors', async () => {
+      // Reconfigure epubjs mock to reject metadata
+      jest.resetModules();
+      setupDomSkeleton();
+      global.FileReader = MockFileReader;
+
+      jest.doMock('epubjs', () => {
+        const mockLocations = {
+          generate: jest.fn(() => Promise.resolve()),
+          length: jest.fn(() => 1),
+          cfiFromLocation: jest.fn((loc) => `epubcfi(/6/${loc})`),
+          locationFromCfi: jest.fn(() => 0),
+        };
+        const mockBook = {
+          ready: Promise.resolve(),
+          renderTo: jest.fn(() => ({
+            display: jest.fn(() => Promise.resolve()),
+            on: jest.fn(),
+            prev: jest.fn(),
+            next: jest.fn(),
+          })),
+          loaded: { metadata: Promise.reject(new Error('meta fail')) },
+          locations: mockLocations,
+          navigation: { toc: Promise.resolve([]) },
+        };
+        const ePub = jest.fn(() => mockBook);
+        ePub.__mock = { mockBook, mockLocations };
+        return { __esModule: true, default: ePub };
+      });
+
+      const mainMocks2 = await import('../../src/main');
+      await import('../../src/library');
+      const mod = await import('../../src/book.js');
+
+      const file = new Blob([new Uint8Array([1])], { type: 'application/epub+zip' });
+      Object.defineProperty(file, 'name', { value: 'ok.epub' });
+
+      mod.openBook({ target: { files: [file] } });
+      await Promise.resolve();
+      await new Promise(setImmediate);
+
+      const title = document.getElementById('book-title');
+      expect(title.textContent).toBe('EPUB Book');
+      expect(mainMocks2.showLoading).toHaveBeenCalled();
+      expect(mainMocks2.hideLoading).toHaveBeenCalled();
+    });
+  });
+
+  describe('TOC generation click behavior', () => {
+    test('clicking a TOC item displays the href and closes overlay', async () => {
+      // Load to trigger generateToc
+      const file = new Blob([new Uint8Array([1])], { type: 'application/epub+zip' });
+      Object.defineProperty(file, 'name', { value: 'ok.epub' });
+      bookModule.openBook({ target: { files: [file] } });
+      await Promise.resolve();
+      await new Promise(setImmediate);
+
+      const { mockBook } = (await import('epubjs')).default.__mock;
+      const rendition = mockBook.renderTo.mock.results[0].value;
+
+      const tocContent = document.getElementById('toc-content');
+      expect(tocContent.children.length).toBeGreaterThanOrEqual(1);
+
+      // Open overlay then click item to ensure closeToc is called
+      const tocContainer = document.getElementById('toc-container');
+      const overlay = document.getElementById('overlay');
+      tocContainer.classList.add('open');
+      overlay.classList.add('open');
+
+      const first = tocContent.children[0];
+      first.dispatchEvent(new Event('click', { bubbles: true }));
+
+      expect(rendition.display).toHaveBeenCalledWith('ch1.xhtml');
+      expect(tocContainer.classList.contains('open')).toBe(false);
+      expect(overlay.classList.contains('open')).toBe(false);
+    });
+  });
+});