diff --git a/src/app/[lang]/__tests__/card.test.tsx b/src/app/[lang]/__tests__/card.test.tsx
index 3ba6f57e..b0a57475 100644
--- a/src/app/[lang]/__tests__/card.test.tsx
+++ b/src/app/[lang]/__tests__/card.test.tsx
@@ -5,6 +5,7 @@ import Article from '../Article';
 
 describe('Article component', () => {
   it('should render correct element', () => {
+    // Arrange
     const data: DataFrontmatter = {
       id: 'test_id',
       title: 'title test',
@@ -17,13 +18,11 @@ describe('Article component', () => {
       tags: ['tag_A', 'tag_B'],
       description: 'description test',
     };
-
     render(<Article {...data} />);
-
     const article = screen.getByRole('article');
     const image = screen.getByRole('img');
     const heading = screen.getByRole('heading');
-
+    // Assert
     expect(article).toBeInTheDocument();
     expect(image).toHaveAttribute('src', data.image);
     expect(image).toHaveAttribute('alt', `${data.title} cover`);
diff --git a/src/app/[lang]/__tests__/footer.test.tsx b/src/app/[lang]/__tests__/footer.test.tsx
index 089cbbad..f64fe575 100644
--- a/src/app/[lang]/__tests__/footer.test.tsx
+++ b/src/app/[lang]/__tests__/footer.test.tsx
@@ -3,12 +3,11 @@ import Footer from '../Footer';
 
 describe('Footer component', () => {
   it('should render correct element', () => {
+    // Arrange
     const footerCopyright = 'footer copyright';
-
     render(<Footer copyright={footerCopyright} />);
-
     const footer = screen.getByRole('contentinfo');
-
+    // Assert
     expect(footer).toBeInTheDocument();
     expect(footer).toHaveTextContent(footerCopyright);
   });
diff --git a/src/app/[lang]/__tests__/header.test.tsx b/src/app/[lang]/__tests__/header.test.tsx
index fdb2fb49..f17bbe08 100644
--- a/src/app/[lang]/__tests__/header.test.tsx
+++ b/src/app/[lang]/__tests__/header.test.tsx
@@ -1,89 +1,76 @@
 import { act, render, screen, waitFor } from '@testing-library/react';
 import Header, { Avatar } from '../Header';
 
+const scrollDownTo = (to: number) => {
+  act(() => {
+    window.scrollY = to - 1;
+    window.dispatchEvent(new Event('scroll'));
+    window.scrollY = to;
+    window.dispatchEvent(new Event('scroll'));
+  });
+}
+const scrollUpTo = (to: number) => {
+  act(() => {
+    window.scrollY = to + 1;
+    window.dispatchEvent(new Event('scroll'));
+    window.scrollY = to;
+    window.dispatchEvent(new Event('scroll'));
+  });
+}
+
 describe('Header component', () => {
   const avatar = (
     <Avatar src="https://external.com/test.jpg" alt="test avatar image alt" />
   );
 
   it('should render correct element', () => {
+    // Arrange
     render(<Header avatar={avatar} />);
-
     const brandLink = screen.getByRole('img');
-
+    // Assert
     expect(brandLink).toBeInTheDocument();
     expect(brandLink.parentElement).toHaveAttribute('href', '/');
   });
 
   it('should hide header on scroll down and show on scroll up', async () => {
+    // Arrange
     render(<Header avatar={avatar} scrollThreshold={100} />);
-
     const header = screen.getByRole('banner');
-
     expect(header.tagName).toBe('HEADER');
 
-    act(() => {
-      window.scrollY = 19;
-      window.dispatchEvent(new Event('scroll'));
-      window.scrollY = 20;
-      window.dispatchEvent(new Event('scroll'));
-    });
-
+    // Act
+    scrollDownTo(20);
+    // Assert
     await waitFor(() => {
       expect(header).toHaveStyle({ '--header-translate-y': '0px' });
     });
-
-    act(() => {
-      window.scrollY = 98;
-      window.dispatchEvent(new Event('scroll'));
-      window.scrollY = 99;
-      window.dispatchEvent(new Event('scroll'));
-    });
-
+    // Act
+    scrollDownTo(99);
+    // Assert
     await waitFor(() => {
       expect(header).toHaveStyle({ '--header-translate-y': '0px' });
     });
-
-    act(() => {
-      window.scrollY = 149;
-      window.dispatchEvent(new Event('scroll'));
-      window.scrollY = 150;
-      window.dispatchEvent(new Event('scroll'));
-    });
-
+    // Act
+    scrollDownTo(150);
+    // Assert
     await waitFor(() => {
       expect(header).toHaveStyle({ '--header-translate-y': '50px' });
     });
-
-    act(() => {
-      window.scrollY = 299;
-      window.dispatchEvent(new Event('scroll'));
-      window.scrollY = 300;
-      window.dispatchEvent(new Event('scroll'));
-    });
-
+    // Act
+    scrollDownTo(800);
+    // Assert
     await waitFor(() => {
       expect(header).toHaveStyle({ '--header-translate-y': '50px' });
     });
-
-    act(() => {
-      window.scrollY = 501;
-      window.dispatchEvent(new Event('scroll'));
-      window.scrollY = 500;
-      window.dispatchEvent(new Event('scroll'));
-    });
-
+    // Act
+    scrollUpTo(500);
+    // Assert
     await waitFor(() => {
       expect(header).toHaveStyle({ '--header-translate-y': '300px' });
     });
-
-    act(() => {
-      window.scrollY = 1;
-      window.dispatchEvent(new Event('scroll'));
-      window.scrollY = 0;
-      window.dispatchEvent(new Event('scroll'));
-    });
-
+    // Act
+    scrollUpTo(0);
+    // Assert
     await waitFor(() => {
       expect(header).toHaveStyle({ '--header-translate-y': '300px' });
     });
diff --git a/src/app/[lang]/__tests__/layout.test.tsx b/src/app/[lang]/__tests__/layout.test.tsx
index 63ac307a..e4a8c775 100644
--- a/src/app/[lang]/__tests__/layout.test.tsx
+++ b/src/app/[lang]/__tests__/layout.test.tsx
@@ -3,24 +3,21 @@ import { locales } from '~/i18n';
 import mockPathname from '~/tests/navigation';
 import Layout, { generateMetadata, generateStaticParams } from '../layout';
 
-describe('I18n layout component', () => {
+describe('I18n layout', () => {
   it('should render correct element', async () => {
+    // Arrange
     const testText = 'Test layout component';
-
     mockPathname.mockReturnValueOnce('/');
-
     const layout = await Layout({
       children: <h2>{testText}</h2>,
       params: { lang: 'en' }
     });
-
     render(layout);
-
     const testChildren = await screen.findByRole('heading');
     const header = await screen.findByRole('banner');
     const nav = await screen.findByRole('navigation');
     const footer = await screen.findByRole('contentinfo');
-
+    // Assert
     expect(testChildren).toHaveTextContent(testText);
     expect(header).toBeInTheDocument();
     expect(nav).toBeInTheDocument();
@@ -28,17 +25,19 @@ describe('I18n layout component', () => {
   });
 
   it('should generate correct metadata', async () => {
+    // Arrange
     const metadata = await generateMetadata({
       params: { lang: 'en' },
     });
-
+    // Assert
     expect(metadata).toBeTruthy();
   });
 
   it('should generate correct static params', async () => {
+    // Arrange
     const staticParams = await generateStaticParams();
     const expected = locales.map(lang => ({ lang }));
-
+    // Assert
     expect(staticParams).toStrictEqual(expected);
   });
 });
diff --git a/src/app/[lang]/__tests__/menu.test.tsx b/src/app/[lang]/__tests__/menu.test.tsx
index 8e7c0a15..cc487ebb 100644
--- a/src/app/[lang]/__tests__/menu.test.tsx
+++ b/src/app/[lang]/__tests__/menu.test.tsx
@@ -3,53 +3,48 @@ import mockPathname from '~/tests/navigation';
 import Menu, { MenuProps } from '../Menu';
 
 describe('Menu component', () => {
-  const menu: MenuProps['menu'] = [
-    { text: 'Home', href: '/' },
-    { text: 'Post', href: '/posts' },
-  ];
-
   it('should render correct element', () => {
+    // Arrange
+    const menu: MenuProps['menu'] = [
+      { text: 'Home', href: '/' },
+      { text: 'Post', href: '/posts' },
+    ];
     mockPathname.mockReturnValue('/');
-
     render(<Menu menu={menu} />);
-
     const nav = screen.getByRole('navigation');
     const linkA = screen.getByRole('link', { name: menu[0].text });
     const linkB = screen.getByRole('link', { name: menu[1].text });
-
+    // Assert
     expect(nav).toBeInTheDocument();
     expect(nav.tagName).toBe('NAV');
-
     expect(linkA).toHaveTextContent(menu[0].text);
     expect(linkA).toHaveAttribute('href', menu[0].href);
-
     expect(linkB).toHaveTextContent(menu[1].text);
     expect(linkB).toHaveAttribute('href', menu[1].href);
   });
 
   it.each([
-    ['/', menu[0].text],
-    ['/posts', menu[1].text],
-    ['/en', menu[0].text],
-    ['/en/posts', menu[1].text],
-    ['/en/posts/test', menu[1].text],
+    ['Home', 'Post', '/'],
+    ['Post', 'Home', '/posts'],
+    ['Home', 'Post', '/en'],
+    ['Post', 'Home', '/en/posts'],
+    ['Post', 'Home', '/en/posts/test'],
   ])(
     'should render correct active link based on the pathname "%s"',
-    (pathname, activeLinkText) => {
+    (activeLinkText, otherLinkText, pathname) => {
+      // Arrange
+      const menu: MenuProps['menu'] = [
+        { text: 'Home', href: '/' },
+        { text: 'Post', href: '/posts' },
+      ];
       mockPathname.mockReturnValue(pathname);
-
       render(<Menu menu={menu} />);
-
-      const links = screen.getAllByRole('link');
+      const activeLink = screen.getByRole('link', { name: activeLinkText });
+      const otherLink = screen.getByRole('link', { name: otherLinkText });
       const activeClassName = 'neon-text';
-
-      links.forEach((link) => {
-        if (link.textContent === activeLinkText) {
-          expect(link).toHaveClass(activeClassName);
-        } else {
-          expect(link).not.toHaveClass(activeClassName);
-        }
-      });
+      // Assert
+      expect(activeLink).toHaveClass(activeClassName);
+      expect(otherLink).not.toHaveClass(activeClassName);
     }
   );
 });
diff --git a/src/app/[lang]/__tests__/page.test.tsx b/src/app/[lang]/__tests__/page.test.tsx
index 75c058e2..2a6192e6 100644
--- a/src/app/[lang]/__tests__/page.test.tsx
+++ b/src/app/[lang]/__tests__/page.test.tsx
@@ -3,27 +3,25 @@ import en from '~/i18n/locales/en';
 import Page, { generateMetadata } from '../page';
 
 jest.mock('@/utils/mdx', () => ({
-  getAllDataFrontmatter: () => []
+  getAllDataFrontmatter: () => [],
 }));
 
 describe('Root page component', () => {
   it('should render correct element', async () => {
-    const page = await Page({
-      params: { lang: 'en' },
-    });
-
+    // Arrange
+    const page = await Page({ params: { lang: 'en' } });
     render(page);
-
     const heading = await screen.findByRole('heading', { level: 1 });
-
+    // Assert
     expect(heading).toBeInTheDocument();
   });
 
   it('should generate correct metadata', async () => {
+    // Arrange
     const metadata = await generateMetadata({
       params: { lang: 'en' },
     });
-
+    // Assert
     expect(metadata).toStrictEqual({ title: en.common.home });
   });
 });
diff --git a/src/app/[lang]/posts/[postId]/__tests__/page.test.tsx b/src/app/[lang]/posts/[postId]/__tests__/page.test.tsx
index caaee9bd..57e7b75a 100644
--- a/src/app/[lang]/posts/[postId]/__tests__/page.test.tsx
+++ b/src/app/[lang]/posts/[postId]/__tests__/page.test.tsx
@@ -7,7 +7,7 @@ const mockData = jest.fn();
 
 jest.mock('next/navigation', () => ({
   notFound: () => mockNotFound(),
-  usePathname: () => ''
+  usePathname: () => '',
 }));
 
 jest.mock('@/components/TableOfContents', () => () => null);
@@ -17,16 +17,16 @@ jest.mock('@/utils/mdx', () => ({
   getDataById: () => mockData(),
 }));
 
-describe('Post page component', () => {
-  beforeEach(() => {
-    mockNotFound.mockClear();
-    mockDataList.mockClear();
-    mockData.mockClear();
-  });
+beforeEach(() => {
+  mockNotFound.mockClear();
+  mockDataList.mockClear();
+  mockData.mockClear();
+});
 
-  it('should render correct element', async () => {
+describe('[postId] page', () => {
+  it('should render correct page', async () => {
+    // Arrange
     const testText = 'test content';
-
     mockData.mockReturnValueOnce({
       id: 'test-id',
       content: <h2>{testText}</h2>,
@@ -36,63 +36,57 @@ describe('Post page component', () => {
         title: 'test title',
       },
     });
-
     const page = await Page({
       params: { postId: 'test-id' },
     });
-
     render(page);
-
     const heading = await screen.findByRole('heading', { level: 1 });
-
+    // Assert
     expect(heading).toBeInTheDocument();
   });
 
-  it('should generate correct metadata', async () => {
-    const expected = {
-      date: '2023/10/28',
-      title: 'test title',
-    };
-
-    mockData.mockReturnValueOnce({ frontmatter: expected });
-
-    const metadata = await generateMetadata({
-      params: { postId: 'test-id' },
-    });
-
-    expect(metadata).toStrictEqual(expected);
+  it('should call notFound when post data is null', async () => {
+    // Arrange
+    mockData.mockReturnValue(null);
+    await Page({ params: { postId: 'test-id' } });
+    // Assert
+    expect(mockNotFound).toBeCalled();
   });
+});
+
+describe('generate static params', () => {
 
   it('should generate correct static params', async () => {
-    const source = [
-      {
-        id: 'test-id-1',
-      },
-      {
-        id: 'test-id-2',
-      },
-    ];
+    // Arrange
+    const source = [{ id: 'test-id-1' }, { id: 'test-id-2' }];
     mockDataList.mockReturnValueOnce(source);
     const staticParams = await generateStaticParams();
     const expected = source.map(({ id }) => ({ postId: id }));
-
+    // Assert
     expect(staticParams).toStrictEqual(expected);
   });
+});
 
-  it('should call notFound when post data is null', async () => {
-    mockData.mockReturnValue(null);
+describe('generate metadata', () => {
 
-    await Page({
+  it('should generate correct metadata', async () => {
+    // Arrange
+    const expected = {
+      date: '2023/10/28',
+      title: 'test title',
+    };
+    mockData.mockReturnValueOnce({ frontmatter: expected });
+    const metadata = await generateMetadata({
       params: { postId: 'test-id' },
     });
+    // Assert
+    expect(metadata).toStrictEqual(expected);
+  });
 
+  it('should call notFound when post data is null', async () => {
+    // Arrange
+    await generateMetadata({ params: { postId: 'test-id' } });
+    // Assert
     expect(mockNotFound).toBeCalled();
-    expect(mockNotFound).toBeCalledTimes(1);
-
-    await generateMetadata({
-      params: { postId: 'test-id' },
-    });
-
-    expect(mockNotFound).toBeCalledTimes(2);
   });
 });
diff --git a/src/app/[lang]/posts/__tests__/page.test.tsx b/src/app/[lang]/posts/__tests__/page.test.tsx
index fc60ef1a..0cb9d111 100644
--- a/src/app/[lang]/posts/__tests__/page.test.tsx
+++ b/src/app/[lang]/posts/__tests__/page.test.tsx
@@ -3,27 +3,25 @@ import en from '~/i18n/locales/en';
 import Page, { generateMetadata } from '../page';
 
 jest.mock('@/utils/mdx', () => ({
-  getAllDataFrontmatter: () => []
+  getAllDataFrontmatter: () => [],
 }));
 
-describe('Posts page component', () => {
+describe('Posts page', () => {
   it('should render correct element', async () => {
-    const page = await Page({
-      params: { lang: 'en' },
-    });
-
+    // Arrange
+    const page = await Page({ params: { lang: 'en' } });
     render(page);
-
     const heading = await screen.findByRole('heading', { level: 1 });
-
+    // Assert
     expect(heading).toBeInTheDocument();
   });
 
   it('should generate correct metadata', async () => {
+    // Arrange
     const metadata = await generateMetadata({
       params: { lang: 'en' },
     });
-
+    // Assert
     expect(metadata).toStrictEqual({ title: en.common.posts });
   });
 });
diff --git a/src/app/layout.tsx b/src/app/layout.tsx
index 225bf3b6..f4afae7c 100644
--- a/src/app/layout.tsx
+++ b/src/app/layout.tsx
@@ -23,7 +23,7 @@ function HtmlLayout({ children }: React.PropsWithChildren) {
   return (
     <Html>
       <body>
-        <div className="lattice fixed inset-x-0 top-0 -z-50 h-screen">
+        <div className="bg-lattice fixed inset-x-0 top-0 -z-50 h-screen">
           <Container className="h-screen bg-zinc-50/70 shadow shadow-zinc-500/50 dark:bg-zinc-950/70" />
         </div>
         <Providers>{children}</Providers>
diff --git a/src/app/not-found.tsx b/src/app/not-found.tsx
index c9795ef4..99678784 100644
--- a/src/app/not-found.tsx
+++ b/src/app/not-found.tsx
@@ -1,12 +1,17 @@
 import type { Metadata } from 'next';
-import NotFound from '@/components/NotFound';
+import { H2 } from '@/components/Heading';
 
 export const metadata: Metadata = {
   title: 'Page not found',
 };
 
 function NotFoundPage() {
-  return <NotFound />;
+  return (
+    <div className="flex h-screen items-center justify-center">
+      <H2>Page not found</H2>
+      <p>Sorry, the page you are looking for does not exist.</p>
+    </div>
+  );
 }
 
 export default NotFoundPage;
diff --git a/src/components/CodeBox/codeBox.test.tsx b/src/components/CodeBox/codeBox.test.tsx
index d20eed8c..88e57268 100644
--- a/src/components/CodeBox/codeBox.test.tsx
+++ b/src/components/CodeBox/codeBox.test.tsx
@@ -5,13 +5,12 @@ import CodeBox from '.';
 
 describe('CodeBox component', () => {
   it('should render correct element', () => {
-    const code = 'Hello world!';
-
+    // Arrange
+    const code = 'should render correct element';
     render(<CodeBox>{code}</CodeBox>);
-
     const copyButton = screen.getByRole('button');
     const codeBox = screen.getByText(code);
-
+    // Assert
     expect(copyButton).toBeInTheDocument();
     expect(codeBox).toBeInTheDocument();
     expect(codeBox).toHaveTextContent(code);
@@ -19,27 +18,23 @@ describe('CodeBox component', () => {
   });
 
   it('should correctly copy the text when clicked', async () => {
+    // Arrange
     Object.assign(navigator, {
       clipboard: {
         writeText: jest.fn().mockImplementation(() => Promise.resolve()),
       },
     });
-
-    const code = 'Hello world!';
-
+    const code = 'should correctly copy the text when clicked';
     render(<CodeBox>{code}</CodeBox>);
-
     const copyButton = screen.getByRole('button');
-
     expect(screen.queryByText('複製成功！')).toHaveClass('opacity-0');
-
+    // Act
     await userEvent.click(copyButton);
     await userEvent.click(copyButton);
-
+    // Assert
     expect(screen.queryByText('複製成功！')).not.toHaveClass('opacity-0');
     expect(navigator.clipboard.writeText).toBeCalledTimes(2);
     expect(navigator.clipboard.writeText).toHaveBeenCalledWith(code);
-
     await waitFor(
       () => {
         expect(screen.queryByText('複製成功！')).toHaveClass('opacity-0');
diff --git a/src/components/Comment/comment.test.tsx b/src/components/Comment/comment.test.tsx
index d8d5559e..a586c67c 100644
--- a/src/components/Comment/comment.test.tsx
+++ b/src/components/Comment/comment.test.tsx
@@ -17,15 +17,13 @@ jest.mock('next-themes', () => ({
 
 describe('Comment component', () => {
   it.each(['light', 'dark'])('should render correct element', async (theme) => {
+    // Arrange
     mockUseTheme.mockReturnValue({ resolvedTheme: theme });
-
     render(<Comment />);
-
     const comment = screen.getByTestId('comment');
     const expectedProps: GiscusProps = JSON.parse(JSON.stringify(giscusConfigs));
-
     expectedProps.theme = `noborder_${theme}`;
-
+    // Assert
     expect(comment).toBeInTheDocument();
     expect(getGiscusProps).toHaveBeenCalledWith(expectedProps);
   });
diff --git a/src/components/Container/container.test.tsx b/src/components/Container/container.test.tsx
index a6da061d..99c05f43 100644
--- a/src/components/Container/container.test.tsx
+++ b/src/components/Container/container.test.tsx
@@ -7,10 +7,10 @@ describe('Container component', () => {
     [undefined, 'DIV'],
     ['main', 'MAIN'],
   ] as const)('should render correct element', async (as, expectedTagName) => {
+    // Arrange
     render(<Container as={as} data-testid="container" />);
-
     const container = screen.getByTestId('container');
-
+    // Assert
     expect(container).toBeInTheDocument();
     expect(container.tagName).toBe(expectedTagName);
   });
diff --git a/src/components/Heading/heading.test.tsx b/src/components/Heading/heading.test.tsx
index 22db7928..76f3150f 100644
--- a/src/components/Heading/heading.test.tsx
+++ b/src/components/Heading/heading.test.tsx
@@ -4,12 +4,11 @@ import Heading, { H1, H2, H3, H4, H5, H6 } from '.';
 
 describe('Heading component', () => {
   it('should render correct element', () => {
+    // Arrange
     const name = 'The heading text';
-
     render(<Heading as="h2">{name}</Heading>);
-
     const heading = screen.getByRole('heading');
-
+    // Assert
     expect(heading).toBeInTheDocument();
     expect(heading).toHaveTextContent(name);
     expect(heading.tagName).toBe('H2');
@@ -23,12 +22,11 @@ describe('Heading component', () => {
     [H5, 'H5'],
     [H6, 'H6'],
   ])('should render correct tag name', (Component, expected) => {
+    // Arrange
     const name = `The ${expected} tag`;
-
     render(<Component>{name}</Component>);
-
     const heading = screen.getByRole('heading');
-
+    // Assert
     expect(heading).toHaveTextContent(name);
     expect(heading.tagName).toBe(expected);
   });
diff --git a/src/components/Image/image.test.tsx b/src/components/Image/image.test.tsx
index 80c52b88..a6b356c2 100644
--- a/src/components/Image/image.test.tsx
+++ b/src/components/Image/image.test.tsx
@@ -6,29 +6,28 @@ describe('Image component', () => {
   it.each([
     {
       alt: 'Test image without specific dimensions',
+      parentTagName: 'PICTURE',
     },
     {
       width: 100,
       height: 100,
       alt: 'Test image with specific dimensions',
+      parentTagName: 'DIV',
     },
     {
       width: 100,
       height: 100,
       alt: 'Test image with base64',
+      parentTagName: 'DIV',
       base64:
         'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mP87wMAAlABTQluYBcAAAAASUVORK5CYII=',
     },
-  ])('should render correct element', ({ alt, ...props }) => {
-    render(<Image src="https://external.com/test.jpg" alt={alt} {...props} style={{ background: '#000' }}/>);
-
-    const checkParentElement = props.width === undefined;
-
+  ])('should render correct element', ({ alt, parentTagName, ...props }) => {
+    // Arrange
+    render(<Image src="https://external.com/test.jpg" alt={alt} {...props} />);
     const image = screen.getByAltText(alt);
+    // Assert
     expect(image.tagName).toBe('IMG');
-
-    if (checkParentElement) {
-      expect(image.parentElement?.tagName).toBe('PICTURE');
-    }
+    expect(image.parentElement?.tagName).toBe(parentTagName);
   });
 });
diff --git a/src/components/Link/link.test.tsx b/src/components/Link/link.test.tsx
index e54b3d80..19787270 100644
--- a/src/components/Link/link.test.tsx
+++ b/src/components/Link/link.test.tsx
@@ -11,10 +11,10 @@ describe('Link component', () => {
     ['https://external.com', 'The external link text', 'https://external.com'],
     [{ pathname: '/internal' }, 'The object href text', '/internal'],
   ])('should render correct element', (href, name, expectedHref) => {
+    // Arrange
     render(<Link href={href as Route}>{name}</Link>);
-
     const link = screen.getByRole('link', { name });
-
+    // Assert
     expect(link).toBeInTheDocument();
     expect(link).toHaveTextContent(name);
     expect(link).toHaveAttribute('href', expectedHref);
@@ -29,15 +29,13 @@ describe('Link component', () => {
   ])(
     'should render correct link element with pathname %s',
     (pathname, expected) => {
+      // Arrange
       const name = 'internal link';
       const href = '/internal';
-
       mockPathname.mockReturnValueOnce(pathname);
-
       render(<Link href={href}>{name}</Link>);
-
       const link = screen.getByRole('link', { name });
-
+      // Assert
       expect(link).toHaveAttribute('href', expected);
     }
   );
diff --git a/src/components/List/list.test.tsx b/src/components/List/list.test.tsx
index 9e43ec0c..21cf6a2e 100644
--- a/src/components/List/list.test.tsx
+++ b/src/components/List/list.test.tsx
@@ -3,17 +3,14 @@ import List from '.';
 
 describe('List component', () => {
   it('should render correct element', () => {
+    // Arrange
     const items = [
       { id: 'id_1', text: 'text_1' },
       { id: 'id_2', text: 'text_2' },
     ];
-
-    const Component = (data: (typeof items)[number]) => <div>{data.text}</div>;
-
-    render(<List Item={Component} items={items} />);
-
+    render(<List Item={(data) => data.text} items={items} />);
     const list = screen.getByRole('list');
-
+    // Assert
     expect(list).toBeInTheDocument();
     expect(list.childNodes.length).toBe(items.length);
     expect(list).toHaveTextContent(items[0].text);
diff --git a/src/components/NotFound/NotFound.tsx b/src/components/NotFound/NotFound.tsx
deleted file mode 100644
index 396a927a..00000000
--- a/src/components/NotFound/NotFound.tsx
+++ /dev/null
@@ -1,25 +0,0 @@
-'use client';
-
-import { Dictionary, getDictionary } from '~/i18n';
-import useI18n from '@/hooks/useI18n';
-import { H1 } from '../Heading';
-import { useEffect, useState } from 'react';
-
-function NotFound() {
-  const { lang } = useI18n();
-  const [dictionary, setDictionary] = useState<Dictionary | null>(null);
-
-  useEffect(() => {
-    getDictionary(lang).then(setDictionary);
-  }, [lang]);
-
-  if (!dictionary) return null;
-
-  return (
-    <div className="flex h-screen items-center justify-center">
-      <H1>{dictionary.notFound.message}</H1>
-    </div>
-  );
-}
-
-export default NotFound;
diff --git a/src/components/NotFound/index.tsx b/src/components/NotFound/index.tsx
deleted file mode 100644
index 2d0c4855..00000000
--- a/src/components/NotFound/index.tsx
+++ /dev/null
@@ -1,3 +0,0 @@
-import NotFound from './NotFound';
-
-export default NotFound;
diff --git a/src/components/NotFound/notFound.test.tsx b/src/components/NotFound/notFound.test.tsx
deleted file mode 100644
index ecd411f9..00000000
--- a/src/components/NotFound/notFound.test.tsx
+++ /dev/null
@@ -1,18 +0,0 @@
-import { render, screen } from '@testing-library/react';
-
-import mockPathname from '~/tests/navigation';
-import en from '~/i18n/locales/en';
-import NotFound from '.';
-
-describe('NotFound component', () => {
-  it('should render correct element', async () => {
-    mockPathname.mockReturnValueOnce('/en/test/path');
-
-    render(<NotFound />);
-
-    const heading = await screen.findByRole('heading');
-
-    expect(heading).toBeInTheDocument();
-    expect(heading).toHaveTextContent(en.notFound.message);
-  });
-});
diff --git a/src/components/TableOfContents/tableOfContents.test.tsx b/src/components/TableOfContents/tableOfContents.test.tsx
index 1f494d56..45512d01 100644
--- a/src/components/TableOfContents/tableOfContents.test.tsx
+++ b/src/components/TableOfContents/tableOfContents.test.tsx
@@ -27,8 +27,8 @@ describe('TableOfContents component', () => {
   });
 
   it('should render correct element', () => {
+    // Arrange
     const source = '# H1\n## H2_1\n### H3_1-1\n## H2_2\n### H3_2-1\n';
-
     mockObserverCallback.mockReturnValueOnce([
       {
         isIntersecting: false,
@@ -39,12 +39,10 @@ describe('TableOfContents component', () => {
         target: { id: 'H3_2-1' },
       },
     ])
-
     render(<TableOfContents source={source} />);
-
     const toc = screen.getByRole('navigation');
     const anchorLinks = screen.getAllByRole('link');
-
+    // Assert
     expect(toc).toBeInTheDocument();
     expect(anchorLinks.length).toBe(4);
     expect(anchorLinks[0]).toHaveAttribute('href', '#H2_1');
diff --git a/src/components/ThemeSwitcher/index.tsx b/src/components/ThemeSwitcher/index.tsx
index 4cc3324c..ab35c909 100644
--- a/src/components/ThemeSwitcher/index.tsx
+++ b/src/components/ThemeSwitcher/index.tsx
@@ -1,3 +1,3 @@
-import ThemeSwitcherProps from './ThemeSwitcher';
+import ThemeSwitcher from './ThemeSwitcher';
 
-export default ThemeSwitcherProps;
+export default ThemeSwitcher;
diff --git a/src/components/ThemeSwitcher/themeSwitcher.test.tsx b/src/components/ThemeSwitcher/themeSwitcher.test.tsx
index 75c59f85..087f5d87 100644
--- a/src/components/ThemeSwitcher/themeSwitcher.test.tsx
+++ b/src/components/ThemeSwitcher/themeSwitcher.test.tsx
@@ -17,30 +17,28 @@ function TestThemeComponent({ children }: PropsWithChildren) {
 
 describe('ThemeSwitch component', () => {
   it('should render correct element', async () => {
+    // Arrange
     setDeviceTheme('light');
-
     render(<TestThemeComponent />);
-
     const button = screen.getByRole('button');
-
+    // Assert
     expect(button).toBeInTheDocument();
   });
 
   it('should correctly switch the theme when clicked', async () => {
+    // Arrange
     setDeviceTheme('dark');
-
     render(<TestThemeComponent />);
-
     const button = screen.getByRole('button');
-
+    // Act
     await userEvent.click(button);
-
+    // Assert
     expect(document.documentElement.getAttribute('style')).toBe(
       'color-scheme: light;'
     );
-
+    // Act
     await userEvent.click(button);
-
+    // Assert
     expect(document.documentElement.getAttribute('style')).toBe(
       'color-scheme: dark;'
     );
diff --git a/src/hooks/__tests__/useAutoReset.test.ts b/src/hooks/__tests__/useAutoReset.test.ts
index d1095835..f12c92b6 100644
--- a/src/hooks/__tests__/useAutoReset.test.ts
+++ b/src/hooks/__tests__/useAutoReset.test.ts
@@ -3,16 +3,16 @@ import useAutoReset from '../useAutoReset';
 
 describe('useAutoReset hook', () => {
   it('should reset state to initial value after a specified delay', async () => {
+    // Arrange
     const initialValue = false;
     const newValue = true;
     const { result } = renderHook(() => useAutoReset(initialValue));
-
+    // Assert
     expect(result.current[0]).toBe(initialValue);
-
+    // Act
     act(() => result.current[1](newValue));
-
+    // Assert
     expect(result.current[0]).toBe(newValue);
-
     await waitFor(
       () => expect(result.current[0]).toBe(initialValue),
       { timeout: 2000 }
diff --git a/src/hooks/__tests__/useI18n.test.ts b/src/hooks/__tests__/useI18n.test.ts
index c2119fdb..2cc02924 100644
--- a/src/hooks/__tests__/useI18n.test.ts
+++ b/src/hooks/__tests__/useI18n.test.ts
@@ -11,10 +11,10 @@ describe('useI18n hook', () => {
   ])(
     'should return the correct language code and dictionary',
     (pathname, expected) => {
+      // Arrange
       mockPathname.mockReturnValueOnce(pathname);
-
       const { result } = renderHook(() => useI18n());
-
+      // Assert
       expect(result.current.lang).toBe(expected);
     }
   );
diff --git a/src/hooks/__tests__/useIntersectionObserver.test.ts b/src/hooks/__tests__/useIntersectionObserver.test.ts
index a7756535..5ebcf5da 100644
--- a/src/hooks/__tests__/useIntersectionObserver.test.ts
+++ b/src/hooks/__tests__/useIntersectionObserver.test.ts
@@ -21,15 +21,15 @@ describe('useIntersectionObserver hook', () => {
   });
 
   it('should observe elements when elementRef is provided', () => {
+    // Arrange
     const elementRef = {
       current: [
         document.createElement('h2'),
         document.createElement('h2')
       ]
     }
-
     renderHook(() => useIntersectionObserver({ elementRef }));
-
+    // Assert
     expect(mockIntersectionObserver).toBeCalledTimes(1);
     expect(mockObserve).toBeCalledTimes(2);
     expect(mockObserve).toBeCalledWith(elementRef.current[0]);
@@ -37,27 +37,27 @@ describe('useIntersectionObserver hook', () => {
   });
 
   it('should observe and disconnect elements when setElementRef is called', () => {
+    // Arrange
     const elementRef = {
       current: [
         document.createElement('h2'),
         document.createElement('h2')
       ]
     }
-
     const { result } = renderHook(() => useIntersectionObserver());
-
+    // Assert
     expect(mockIntersectionObserver).toBeCalledTimes(1);
     expect(mockObserve).toBeCalledTimes(0);
-
+    // Act
     act(() => result.current[1](elementRef.current));
-
+    // Assert
     expect(mockDisconnect).toBeCalledTimes(0);
     expect(mockObserve).toBeCalledTimes(2);
     expect(mockObserve).toBeCalledWith(elementRef.current[0]);
     expect(mockObserve).toHaveBeenLastCalledWith(elementRef.current[1]);
-
+    // Act
     act(() => result.current[1](elementRef.current[0]));
-
+    // Assert
     expect(mockDisconnect).toBeCalledTimes(1);
     expect(mockObserve).toBeCalledTimes(3);
     expect(mockObserve).toHaveBeenLastCalledWith(elementRef.current[0]);
diff --git a/src/hooks/__tests__/useMounted.test.ts b/src/hooks/__tests__/useMounted.test.ts
index 549852e9..82743822 100644
--- a/src/hooks/__tests__/useMounted.test.ts
+++ b/src/hooks/__tests__/useMounted.test.ts
@@ -3,8 +3,9 @@ import useIsMounted from '../useIsMounted';
 
 describe('useIsMounted hook', () => {
   it('should return true if component is mounted', () => {
+    // Arrange
     const { result } = renderHook(() => useIsMounted());
-
+    // Assert
     expect(result.current).toBeTruthy();
   });
 });
diff --git a/src/hooks/__tests__/useScroll.test.ts b/src/hooks/__tests__/useScroll.test.ts
index 3f204d2a..ff81679d 100644
--- a/src/hooks/__tests__/useScroll.test.ts
+++ b/src/hooks/__tests__/useScroll.test.ts
@@ -10,17 +10,23 @@ describe('useScroll hook', () => {
     scrollHandler.mockClear();
   });
 
-  it('should call the scroll handler when window is scrolled', async () => {
+  it('should not call the scroll handler initially', () => {
+    // Arrange
     renderHook(() => useScroll({ handler: scrollHandler }));
-
+    // Assert
     expect(scrollHandler).not.toBeCalled();
+  });
 
+  it('should call the scroll handler when window is scrolled', async () => {
+    // Arrange
+    renderHook(() => useScroll({ handler: scrollHandler }));
+    // Act
     act(() => {
       window.scrollX = 100;
       window.scrollY = 200;
       window.dispatchEvent(new Event('scroll'));
     });
-
+    // Assert
     await waitFor(() => {
       expect(scrollHandler).toBeCalled();
       expect(scrollHandler).toBeCalledTimes(1);
@@ -29,23 +35,21 @@ describe('useScroll hook', () => {
   });
 
   it('should call the scroll handler when a specified element is scrolled', async () => {
+    // Arrange
     const element = document.createElement('div');
-
     renderHook(() =>
       useScroll({
         ref: { current: element },
         handler: scrollHandler,
       })
     );
-
-    expect(scrollHandler).not.toBeCalled();
-
+    // Act
     act(() => {
       element.scrollLeft = 150;
       element.scrollTop = 250;
       element.dispatchEvent(new Event('scroll'));
     });
-
+    // Assert
     await waitFor(() => {
       expect(scrollHandler).toBeCalled();
       expect(scrollHandler).toBeCalledTimes(1);
@@ -54,90 +58,91 @@ describe('useScroll hook', () => {
   });
 
   it('should switch the element being listened to for scrolling when using register', async () => {
+    // Arrange
     const element = document.createElement('main');
     const { result } = renderHook(() =>
       useScroll({
         handler: scrollHandler,
       })
     );
-
+    // Act
     act(() => {
       window.scrollX = 0;
       window.scrollY = 80;
       window.dispatchEvent(new Event('scroll'));
     });
-
+    // Assert
     await waitFor(() => {
       expect(scrollHandler).toBeCalled();
       expect(scrollHandler).toBeCalledTimes(1);
-      expect(scrollHandler).toBeCalledWith({ x: 0, y: 80 }, window);
+      expect(scrollHandler).toHaveBeenLastCalledWith({ x: 0, y: 80 }, window);
     });
-
+    // Act
     act(() => {
       result.current.register(element);
       element.scrollLeft = 180;
       element.scrollTop = 280;
       element.dispatchEvent(new Event('scroll'));
     });
-
+    // Assert
     await waitFor(() => {
-      expect(scrollHandler).toBeCalled();
       expect(scrollHandler).toBeCalledTimes(2);
-      expect(scrollHandler).toBeCalledWith({ x: 180, y: 280 }, element);
+      expect(scrollHandler).toHaveBeenLastCalledWith(
+        { x: 180, y: 280 },
+        element
+      );
     });
   });
 
   it('should stop listening to scroll events when remove is called', async () => {
+    // Arrange
     const { result } = renderHook(() =>
       useScroll({
         handler: scrollHandler,
       })
     );
-
-    expect(scrollHandler).not.toBeCalled();
-
+    // Act
     act(() => {
       result.current.remove();
       window.scrollX = 100;
       window.scrollY = 0;
       window.dispatchEvent(new Event('scroll'));
     });
-
+    // Assert
     await waitFor(() => {
       expect(scrollHandler).not.toBeCalled();
     });
   });
 
   it('should stop listening to scroll events when the component is unmounted', async () => {
+    // Arrange
     const { unmount } = renderHook(() =>
       useScroll({
         handler: scrollHandler,
       })
     );
-
-    expect(scrollHandler).not.toBeCalled();
-
+    // Act
     unmount();
-
     act(() => {
       window.scrollX = 100;
       window.scrollY = 0;
       window.dispatchEvent(new Event('scroll'));
     });
-
+    // Assert
     await waitFor(() => {
       expect(scrollHandler).not.toBeCalled();
     });
   });
 
   it('should trigger the scroll handler on initial render', async () => {
+    // Arrange
     renderHook(() =>
       useScroll({
         handler: scrollHandler,
         initial: true,
       })
     );
-
+    // Assert
     await waitFor(() => {
       expect(scrollHandler).toBeCalled();
       expect(scrollHandler).toBeCalledTimes(1);
diff --git a/src/plugins/__tests__/rehypeImageMetadata.test.ts b/src/plugins/__tests__/rehypeImageMetadata.test.ts
index 9742d2d3..84f2de97 100644
--- a/src/plugins/__tests__/rehypeImageMetadata.test.ts
+++ b/src/plugins/__tests__/rehypeImageMetadata.test.ts
@@ -32,6 +32,7 @@ describe('Rehype image metadata function', () => {
   });
 
   it('should format paragraph with image element to a div', async () => {
+    // Arrange
     const testImageNode: ImageNode = {
       type: 'element',
       tagName: 'img',
@@ -44,15 +45,17 @@ describe('Rehype image metadata function', () => {
       tagName: 'p',
       children: [testImageNode],
     };
+    // Act
     const transformer = rehypeImageMetadata();
     const result = await transformer(testTree);
-
+    // Assert
     expect(result.tagName).toBe('div');
   });
 
   it.each(['/test.jpeg', '/public/test.jpeg'])(
     'should set image properties for src: %s',
     async (src) => {
+      // Arrange
       const width = 2;
       const height = 1;
       const fileType = 'png';
@@ -67,16 +70,20 @@ describe('Rehype image metadata function', () => {
         info: { format: fileType },
         data: base64,
       });
+      // Act
       const transformer = rehypeImageMetadata();
       const result = await transformer(testImageNode);
-
-      expect(result.tagName).toBe(testImageNode.tagName);
-      expect(result.properties.src).toBe(testImageNode.properties.src);
-      expect(result.properties.width).toBe(width);
-      expect(result.properties.height).toBe(height);
-      expect(result.properties.base64).toBe(
-        `data:image/${fileType};base64,${base64}`
-      );
+      // Assert
+      expect(result).toStrictEqual({
+        type: 'element',
+        tagName: testImageNode.tagName,
+        properties: {
+          src: testImageNode.properties.src,
+          width,
+          height,
+          base64: `data:image/${fileType};base64,${base64}`,
+        },
+      });
     }
   );
 });
diff --git a/src/utils/__tests__/clipboard.test.ts b/src/utils/__tests__/clipboard.test.ts
index dfbce4e4..ac493e89 100644
--- a/src/utils/__tests__/clipboard.test.ts
+++ b/src/utils/__tests__/clipboard.test.ts
@@ -26,26 +26,30 @@ describe('Copy to clipboard function', () => {
   });
 
   it('should return error with reject', async () => {
+    // Arrange
     expect.assertions(1);
-
-    await expect(copyToClipboard('test')).rejects.toStrictEqual(
-      TypeError('document.execCommand is not a function')
-    );
+    const expected = TypeError('document.execCommand is not a function');
+    // Act
+    const result = copyToClipboard('test');
+    // Assert
+    await expect(result).rejects.toStrictEqual(expected);
   });
 
   it('should call document execCommand', () => {
+    // Arrange
     setDeviceClipboard('old');
-
+    // Act
     copyToClipboard('test');
-
+    // Assert
     expect(document.execCommand).toBeCalled();
   });
 
   it('should call navigator clipboard writeText', () => {
+    // Arrange
     setDeviceClipboard('new');
-
+    // Act
     copyToClipboard('test');
-
+    // Assert
     expect(navigator.clipboard.writeText).toHaveBeenCalledWith('test');
   });
 });
diff --git a/src/utils/__tests__/cn.test.ts b/src/utils/__tests__/cn.test.ts
index db64d979..c4647f00 100644
--- a/src/utils/__tests__/cn.test.ts
+++ b/src/utils/__tests__/cn.test.ts
@@ -2,8 +2,13 @@ import cn from '../cn';
 
 describe('TailwindCSS className merge function', () => {
   it('should return current className', () => {
-    const className = cn('bg-blue-500 text-white/90', { 'bg-red-500': true });
-
-    expect(className).toBe('text-white/90 bg-red-500');
+    // Arrange
+    const baseClassName = 'bg-blue-500 text-white/90';
+    const mergeClassName = { 'bg-red-500': true };
+    const expected = 'text-white/90 bg-red-500';
+    // Act
+    const className = cn(baseClassName, mergeClassName);
+    // Assert
+    expect(className).toBe(expected);
   });
 });
diff --git a/src/utils/__tests__/date.test.ts b/src/utils/__tests__/date.test.ts
index 931b6b93..3d5b4497 100644
--- a/src/utils/__tests__/date.test.ts
+++ b/src/utils/__tests__/date.test.ts
@@ -2,26 +2,29 @@ import { compareDates, formatDate } from '../date';
 
 describe('Format date function', () => {
   it('should display the date format in Taiwan', () => {
-    const date = formatDate(new Date('2023/7/8'));
-
-    expect(date).toBe('2023年7月8日');
+    // Arrange
+    const date = new Date('2023/7/8');
+    const expected = '2023年7月8日';
+    // Act
+    const result = formatDate(date);
+    // Assert
+    expect(result).toBe(expected);
   });
 
   it('should display the date format in American', () => {
-    const date = formatDate('2023/7/8', 'en-us');
-
-    expect(date).toBe('July 8, 2023');
+    // Arrange
+    const date = '2023/7/8';
+    const expected = 'July 8, 2023';
+    // Act
+    const result = formatDate(date, 'en-us');
+    // Assert
+    expect(result).toBe(expected);
   });
 });
 
 describe('Compare dates function', () => {
-  it('should return correct relative order', () => {
-    expect(compareDates('2023/12/25', '2023/1/1')).toBe(-1);
-    expect(compareDates('2023/10/10', '2023/12/31')).toBe(1);
-    expect(compareDates('2023/2/28', '2023/2/28')).toBe(1);
-  });
-
-  it('should sort dates in ascending and descending order', () => {
+  it('should sort dates in descending order', () => {
+    // Arrange
     const dates: DateOrDateString[] = [
       '2023/2/2',
       '2023/11/1',
@@ -29,17 +32,39 @@ describe('Compare dates function', () => {
       '2023/10/1',
       '2023/1/1',
     ];
-    const descendingExpected = [
+    const expected = [
       '2023/11/1',
       '2023/10/1',
       '2023/2/2',
       '2023/2/1',
       '2023/1/1',
     ];
-
-    expect(dates.sort(compareDates)).toStrictEqual(descendingExpected);
-    expect(
-      dates.sort((date1, date2) => compareDates(date1, date2, true))
-    ).toStrictEqual(descendingExpected.concat().reverse());
+    // Act
+    const result = dates.sort(compareDates);
+    // Assert
+    expect(result).toStrictEqual(expected);
+  });
+  it('should sort dates in ascending order', () => {
+    // Arrange
+    const dates: DateOrDateString[] = [
+      '2023/2/2',
+      '2023/11/1',
+      '2023/2/1',
+      '2023/10/1',
+      '2023/1/1',
+    ];
+    const expected = [
+      '2023/1/1',
+      '2023/2/1',
+      '2023/2/2',
+      '2023/10/1',
+      '2023/11/1',
+    ];
+    // Act
+    const result = dates.sort((date1, date2) =>
+      compareDates(date1, date2, true)
+    );
+    // Assert
+    expect(result).toStrictEqual(expected);
   });
 });
diff --git a/src/utils/__tests__/generateRSS.test.ts b/src/utils/__tests__/generateRSS.test.ts
index 54dde271..17eb2063 100644
--- a/src/utils/__tests__/generateRSS.test.ts
+++ b/src/utils/__tests__/generateRSS.test.ts
@@ -4,6 +4,7 @@ import { defaultLocale } from '~/i18n';
 import generateRSS, { PUBLIC_FEED_PATH } from '../generateRSS';
 
 const mockWriteFile = jest.fn();
+const mockAtom1 = (options: unknown) => `atom1 - ${JSON.stringify(options)}`;
 
 jest.mock('feed', () => ({
   Feed: class MockFeed {
@@ -11,7 +12,7 @@ jest.mock('feed', () => ({
     constructor(options: FeedOptions) {
       this._options = options;
     }
-    atom1 = () => `atom1 - ${JSON.stringify(this._options)}`;
+    atom1 = () => mockAtom1(this._options);
   },
 }));
 
@@ -27,35 +28,41 @@ describe('Generate RSS function', () => {
   });
 
   it('should generate the rss for the specified language', () => {
+    // Arrange
     const testFeedOptions: FeedOptions = {
       id: 'http://test.generate.rss',
       title: 'test generate RSS',
       copyright: `Copyright © ${new Date().getFullYear()}`,
       language: 'en',
     };
-
+    const expectedFileName = 'atom.en.xml';
+    const expectedFileContent = mockAtom1(testFeedOptions);
+    // Act
     generateRSS(testFeedOptions);
-
+    // Assert
     expect(mockWriteFile).toBeCalledTimes(1);
     expect(mockWriteFile).toBeCalledWith(
-      path.join(PUBLIC_FEED_PATH, 'atom.en.xml'),
-      `atom1 - ${JSON.stringify(testFeedOptions)}`
+      path.join(PUBLIC_FEED_PATH, expectedFileName),
+      expectedFileContent
     );
   });
 
   it('should generate the rss for the default language', () => {
+    // Arrange
     const testFeedOptions: FeedOptions = {
       id: 'http://test.generate.rss',
       title: 'test generate RSS',
       copyright: `Copyright © ${new Date().getFullYear()}`,
     };
-
+    const expectedFileName = `atom.${defaultLocale}.xml`;
+    const expectedFileContent = mockAtom1(testFeedOptions);
+    // Act
     generateRSS(testFeedOptions);
-
+    // Assert
     expect(mockWriteFile).toBeCalledTimes(1);
     expect(mockWriteFile).toBeCalledWith(
-      path.join(PUBLIC_FEED_PATH, `atom.${defaultLocale}.xml`),
-      `atom1 - ${JSON.stringify(testFeedOptions)}`
+      path.join(PUBLIC_FEED_PATH, expectedFileName),
+      expectedFileContent
     );
   });
 });
diff --git a/src/utils/__tests__/getLocale.test.ts b/src/utils/__tests__/getLocale.test.ts
index 5539d41c..43ff71aa 100644
--- a/src/utils/__tests__/getLocale.test.ts
+++ b/src/utils/__tests__/getLocale.test.ts
@@ -2,10 +2,15 @@ import { defaultLocale } from '~/i18n';
 import getLocale from '../getLocale';
 
 describe('get locale function', () => {
-  it('should return undefined when acceptLanguage does not match and defaultLocale is not provided', () => {
-    expect(getLocale()).toBe(undefined);
-    expect(getLocale('/not/match/locale')).toBe(undefined);
-  });
+  it.each([undefined, '/not/match/locale'])(
+    'should return undefined when acceptLanguage does not match and defaultLocale is not provided',
+    (param) => {
+      // Act
+      const result = getLocale(param);
+      // Assert
+      expect(result).toBe(undefined);
+    }
+  );
 
   it.each([
     ['zh-TW,zh;q=0.9,en-US;q=0.8,en;q=0.7', 'zh'],
@@ -14,7 +19,10 @@ describe('get locale function', () => {
   ])(
     'should extract the preferred language code from the Accept-Language header',
     (acceptLanguage, expected) => {
-      expect(getLocale(acceptLanguage, defaultLocale)).toBe(expected);
+      // Act
+      const result = getLocale(acceptLanguage, defaultLocale);
+      // Assert
+      expect(result).toBe(expected);
     }
   );
 
@@ -26,7 +34,10 @@ describe('get locale function', () => {
   ])(
     'should extract the language code from the path string',
     (pathname, expected) => {
-      expect(getLocale(pathname, defaultLocale)).toBe(expected);
+      // Act
+      const result = getLocale(pathname, defaultLocale);
+      // Assert
+      expect(result).toBe(expected);
     }
   );
 });
diff --git a/src/utils/__tests__/math.test.ts b/src/utils/__tests__/math.test.ts
index ffa613a0..b4bfe1a0 100644
--- a/src/utils/__tests__/math.test.ts
+++ b/src/utils/__tests__/math.test.ts
@@ -1,11 +1,20 @@
 import { toFixedNumber } from '../math';
 
 describe('math function', () => {
-  it('should round a number to the specified number of decimal places', () => {
-    const input = 1.3456;
-    expect(toFixedNumber(0)(input)).toBe(1);
-    expect(toFixedNumber(1)(input)).toBe(1.3);
-    expect(toFixedNumber(2)(input)).toBe(1.35);
-    expect(toFixedNumber(3)(input)).toBe(1.346);
-  });
+  it.each([
+    [0, 1],
+    [1, 1.3],
+    [2, 1.35],
+    [3, 1.346],
+  ])(
+    'should round a number to the specified number of decimal places',
+    (digits, expected) => {
+      // Arrange
+      const input = 1.3456;
+      // Act
+      const result = toFixedNumber(digits)(input);
+      // Assert
+      expect(result).toBe(expected);
+    }
+  );
 });
diff --git a/src/utils/__tests__/mdx.test.ts b/src/utils/__tests__/mdx.test.ts
index 1602f0c8..22826c5a 100644
--- a/src/utils/__tests__/mdx.test.ts
+++ b/src/utils/__tests__/mdx.test.ts
@@ -30,13 +30,14 @@ describe('Get post list function', () => {
   });
 
   it('should get post list descending by date', async () => {
+    // Arrange
     mockReaddir.mockReturnValueOnce(['test_A.md', 'test_B.mdx', 'test_C.md']);
     mockReadFile.mockReturnValueOnce(mockFileA);
     mockReadFile.mockReturnValueOnce(mockFileB);
     mockReadFile.mockReturnValueOnce(mockFileC);
-
+    // Act
     const postList = await getAllDataFrontmatter('posts');
-
+    // Assert
     expect(postList).toStrictEqual([
       { id: 'test_C', date: '2023/07/09' },
       { id: 'test_A', date: '2023/07/08' },
@@ -45,15 +46,15 @@ describe('Get post list function', () => {
   });
 
   it('should return same id error with reject', async () => {
+    // Arrange
+    const expected = Error('Duplicate id "test_A" found in "test_A.mdx"');
     mockReaddir.mockReturnValueOnce(['test_A.md', 'test_A.mdx']);
     mockReadFile.mockReturnValue('');
     expect.assertions(1);
-
-    await expect(
-      getAllDataFrontmatter('posts')
-    ).rejects.toStrictEqual(
-      Error('Duplicate id "test_A" found in "test_A.mdx"')
-    );
+    // Act
+    const result = getAllDataFrontmatter('posts');
+    // Assert
+    await expect(result).rejects.toStrictEqual(expected);
   });
 });
 
@@ -65,11 +66,12 @@ describe('Get post data function', () => {
   });
 
   it('should get post data by mdx file', async () => {
+    // Arrange
     mockExists.mockReturnValueOnce(true);
     mockReadFile.mockReturnValueOnce(mockFileB);
-
+    // Act
     const postData = await getDataById('posts', 'test_B');
-
+    // Assert
     expect(postData).toStrictEqual({
       content: '測試文章B',
       frontmatter: { date: '2023/07/07' },
@@ -79,11 +81,12 @@ describe('Get post data function', () => {
   });
 
   it('should get post data by md file', async () => {
+    // Arrange
     mockExists.mockReturnValueOnce(false);
     mockReadFile.mockReturnValueOnce(mockFileC);
-
+    // Act
     const postData = await getDataById('posts', 'test_C');
-
+    // Assert
     expect(postData).toStrictEqual({
       content: '測試文章C',
       frontmatter: { date: '2023/07/09' },
@@ -93,13 +96,14 @@ describe('Get post data function', () => {
   });
 
   it('should return null when trying to get post data for a non-existing file', async () => {
+    // Arrange
     mockExists.mockReturnValueOnce(false);
     mockReadFile.mockImplementation(() => {
       throw new Error('File not found');
     });
-
+    // Act
     const postData = await getDataById('posts', 'not_found');
-
+    // Assert
     expect(postData).toBe(null);
   });
 });
diff --git a/tailwind.config.js b/tailwind.config.js
index 1c9bec6b..9a7f9981 100644
--- a/tailwind.config.js
+++ b/tailwind.config.js
@@ -57,7 +57,7 @@ const tailwindcssConfig = {
         },
       });
       addComponents({
-        '.lattice': {
+        '.bg-lattice': {
           '--lattice-base-color': theme('colors.stone.50'),
           '--lattice-line-color': 'rgba(0, 0, 0, 0.04)',
           '--lattice-ratio': '10%',
@@ -80,7 +80,7 @@ const tailwindcssConfig = {
             var(--lattice-base-color);`,
           backgroundSize: 'var(--lattice-size);',
         },
-        '.dark .lattice': {
+        '.dark .bg-lattice': {
           '--lattice-base-color': theme('colors.stone.950'),
           '--lattice-line-color': 'rgba(255, 255, 255, 0.04)',
         },
@@ -112,19 +112,19 @@ const tailwindcssConfig = {
       });
       addUtilities({
         '.multiline-ellipsis': {
+          overflow: 'hidden',
           display: '-webkit-box',
           '-webkit-box-orient': 'vertical',
           '-webkit-line-clamp': 'var(--webkit-line-clamp, 2)',
-          overflow: 'hidden',
-        }
+        },
       });
-      [3, 4, 5].forEach(number => {
+      [3, 4, 5].forEach((number) => {
         addUtilities({
           [`.multiline-ellipsis-${number}`]: {
             '--webkit-line-clamp': String(number),
-          }
+          },
         });
-      })
+      });
     }),
   ],
 };