diff --git a/package.json b/package.json
index 89d9182..cdb2d1f 100644
--- a/package.json
+++ b/package.json
@@ -33,6 +33,10 @@
   },
   "devDependencies": {
     "@eslint/js": "^10.0.1",
+    "@testing-library/jest-dom": "^6.9.1",
+    "@testing-library/react": "^16.3.2",
+    "@testing-library/user-event": "^14.6.1",
+    "@types/jsdom": "^21.1.7",
     "@types/react": "^19.2.14",
     "@types/react-dom": "^19.2.3",
     "eslint": "^10.2.1",
@@ -40,6 +44,7 @@
     "eslint-plugin-react-refresh": "^0.5.2",
     "globals": "^17.5.0",
     "husky": "^9.1.7",
+    "jsdom": "^26.0.0",
     "lint-staged": "^16.4.0",
     "prettier": "^3.8.3",
     "typescript-eslint": "^8.58.2",
diff --git a/src/components/terminal/TerminalInput.test.tsx b/src/components/terminal/TerminalInput.test.tsx
index e69de29..7fa17b1 100644
--- a/src/components/terminal/TerminalInput.test.tsx
+++ b/src/components/terminal/TerminalInput.test.tsx
@@ -0,0 +1,40 @@
+import { render, screen, fireEvent } from '@testing-library/react';
+import { TerminalInput } from './TerminalInput';
+import { describe, it, expect, vi } from 'vitest';
+import React from 'react';
+
+describe('TerminalInput component', () => {
+  it('renders correctly', () => {
+    const onChange = vi.fn();
+    const onSubmit = vi.fn();
+    render(<TerminalInput value="" onChange={onChange} onSubmit={onSubmit} />);
+    expect(screen.getByPlaceholderText('Type here...')).toBeInTheDocument();
+  });
+
+  it('calls onChange when typing', () => {
+    const onChange = vi.fn();
+    const onSubmit = vi.fn();
+    render(<TerminalInput value="" onChange={onChange} onSubmit={onSubmit} />);
+    const input = screen.getByPlaceholderText('Type here...');
+    fireEvent.change(input, { target: { value: 'hello' } });
+    expect(onChange).toHaveBeenCalledWith('hello');
+  });
+
+  it('calls onSubmit when Enter is pressed', () => {
+    const onChange = vi.fn();
+    const onSubmit = vi.fn();
+    render(<TerminalInput value="test" onChange={onChange} onSubmit={onSubmit} />);
+    const input = screen.getByPlaceholderText('Type here...');
+    fireEvent.keyDown(input, { key: 'Enter', code: 'Enter' });
+    expect(onSubmit).toHaveBeenCalled();
+  });
+
+  it('clears input when Escape is pressed', () => {
+    const onChange = vi.fn();
+    const onSubmit = vi.fn();
+    render(<TerminalInput value="test" onChange={onChange} onSubmit={onSubmit} />);
+    const input = screen.getByPlaceholderText('Type here...');
+    fireEvent.keyDown(input, { key: 'Escape', code: 'Escape' });
+    expect(onChange).toHaveBeenCalledWith('');
+  });
+});
diff --git a/src/components/ui/Button.test.tsx b/src/components/ui/Button.test.tsx
new file mode 100644
index 0000000..f536318
--- /dev/null
+++ b/src/components/ui/Button.test.tsx
@@ -0,0 +1,16 @@
+import { render, screen } from '@testing-library/react';
+import { Button } from './Button';
+import { describe, it, expect } from 'vitest';
+
+describe('Button component', () => {
+  it('renders children correctly', () => {
+    render(<Button>Click Me</Button>);
+    expect(screen.getByText('Click Me')).toBeInTheDocument();
+  });
+
+  it('shows loading state when loading prop is true', () => {
+    render(<Button loading>Submit</Button>);
+    expect(screen.getByText('⏳')).toBeInTheDocument();
+    expect(screen.getByRole('button')).toBeDisabled();
+  });
+});
diff --git a/src/components/ui/Input.test.tsx b/src/components/ui/Input.test.tsx
new file mode 100644
index 0000000..9447760
--- /dev/null
+++ b/src/components/ui/Input.test.tsx
@@ -0,0 +1,23 @@
+import { render, screen } from '@testing-library/react';
+import { Input } from './Input';
+import { describe, it, expect } from 'vitest';
+import React from 'react';
+
+describe('Input component', () => {
+  it('renders correctly', () => {
+    render(<Input placeholder="Enter text" />);
+    expect(screen.getByPlaceholderText('Enter text')).toBeInTheDocument();
+  });
+
+  it('passes ref correctly', () => {
+    const ref = React.createRef<HTMLInputElement>();
+    render(<Input ref={ref} />);
+    expect(ref.current).toBeInstanceOf(HTMLInputElement);
+  });
+
+  it('applies error styles when hasError is true', () => {
+    render(<Input hasError data-testid="error-input" />);
+    const input = screen.getByTestId('error-input');
+    expect(input.style.border).toContain('var(--status-error)');
+  });
+});
diff --git a/src/components/ui/MarkdownRenderer.test.tsx b/src/components/ui/MarkdownRenderer.test.tsx
new file mode 100644
index 0000000..dc2469e
--- /dev/null
+++ b/src/components/ui/MarkdownRenderer.test.tsx
@@ -0,0 +1,25 @@
+import { render, screen } from '@testing-library/react';
+import { MarkdownRenderer } from './MarkdownRenderer';
+import { describe, it, expect } from 'vitest';
+import React from 'react';
+
+describe('MarkdownRenderer component', () => {
+  it('renders markdown content correctly', () => {
+    render(<MarkdownRenderer content="# Hello World" />);
+    // Testing specific output depends on react-markdown, we just test if the component renders the text
+    expect(screen.getByText('Hello World')).toBeInTheDocument();
+  });
+
+  it('renders code blocks correctly', () => {
+    render(<MarkdownRenderer content="`inline code`" />);
+    expect(screen.getByText('inline code')).toBeInTheDocument();
+    expect(screen.getByText('inline code').tagName).toBe('CODE');
+  });
+
+  it('renders links correctly', () => {
+    render(<MarkdownRenderer content="[GitHub](https://github.com)" />);
+    const link = screen.getByRole('link', { name: 'GitHub' });
+    expect(link).toBeInTheDocument();
+    expect(link).toHaveAttribute('href', 'https://github.com');
+  });
+});
diff --git a/src/components/ui/Panel.test.tsx b/src/components/ui/Panel.test.tsx
new file mode 100644
index 0000000..9ac0af9
--- /dev/null
+++ b/src/components/ui/Panel.test.tsx
@@ -0,0 +1,25 @@
+import { render, screen } from '@testing-library/react';
+import { Panel } from './Panel';
+import { describe, it, expect } from 'vitest';
+import React from 'react';
+
+describe('Panel component', () => {
+  it('renders children correctly', () => {
+    render(<Panel>Panel Content</Panel>);
+    expect(screen.getByText('Panel Content')).toBeInTheDocument();
+  });
+
+  it('renders title when provided', () => {
+    render(<Panel title="Test Title">Content</Panel>);
+    expect(screen.getByText('[ Test Title ]')).toBeInTheDocument();
+  });
+
+  it('renders headerRight when provided', () => {
+    render(
+      <Panel title="Title" headerRight={<button>Action</button>}>
+        Content
+      </Panel>,
+    );
+    expect(screen.getByRole('button', { name: 'Action' })).toBeInTheDocument();
+  });
+});
diff --git a/src/components/ui/ProgressBar.test.tsx b/src/components/ui/ProgressBar.test.tsx
new file mode 100644
index 0000000..824f1be
--- /dev/null
+++ b/src/components/ui/ProgressBar.test.tsx
@@ -0,0 +1,35 @@
+import { render, screen } from '@testing-library/react';
+import { ProgressBar } from './ProgressBar';
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
+import React from 'react';
+
+describe('ProgressBar component', () => {
+  beforeEach(() => {
+    vi.useFakeTimers();
+  });
+
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
+  it('renders correctly with current and total', () => {
+    render(<ProgressBar current={5} total={10} />);
+    expect(screen.getByText(/5\/10 \(50%\)/)).toBeInTheDocument();
+  });
+
+  it('renders label when provided', () => {
+    render(<ProgressBar current={5} total={10} label="Processing" />);
+    expect(screen.getByText('Processing')).toBeInTheDocument();
+  });
+
+  it('hides count when showCount is false', () => {
+    render(<ProgressBar current={5} total={10} showCount={false} />);
+    expect(screen.queryByText(/5\/10 \(50%\)/)).not.toBeInTheDocument();
+  });
+
+  it('shows ETA when startTime is provided', () => {
+    const startTime = Date.now();
+    render(<ProgressBar current={5} total={10} startTime={startTime} />);
+    expect(screen.getByText(/ETA:/)).toBeInTheDocument();
+  });
+});
diff --git a/src/components/ui/ScrollArea.test.tsx b/src/components/ui/ScrollArea.test.tsx
new file mode 100644
index 0000000..8079ef4
--- /dev/null
+++ b/src/components/ui/ScrollArea.test.tsx
@@ -0,0 +1,23 @@
+import { render, screen } from '@testing-library/react';
+import { ScrollArea } from './ScrollArea';
+import { describe, it, expect } from 'vitest';
+import React from 'react';
+
+describe('ScrollArea component', () => {
+  it('renders children correctly', () => {
+    render(<ScrollArea>Scrollable Content</ScrollArea>);
+    expect(screen.getByText('Scrollable Content')).toBeInTheDocument();
+  });
+
+  it('applies maxHeight when provided', () => {
+    render(<ScrollArea maxHeight="200px">Scroll Area Content</ScrollArea>);
+    const element = screen.getByText('Scroll Area Content');
+    expect(element.style.maxHeight).toBe('200px');
+  });
+
+  it('passes innerRef correctly', () => {
+    const ref = React.createRef<HTMLDivElement>();
+    render(<ScrollArea innerRef={ref}>Content</ScrollArea>);
+    expect(ref.current).toBeInstanceOf(HTMLDivElement);
+  });
+});
diff --git a/src/test/setup.ts b/src/test/setup.ts
new file mode 100644
index 0000000..7b0828b
--- /dev/null
+++ b/src/test/setup.ts
@@ -0,0 +1 @@
+import '@testing-library/jest-dom';
diff --git a/vite-env.d.ts b/vite-env.d.ts
index e92b4bd..6560e54 100644
--- a/vite-env.d.ts
+++ b/vite-env.d.ts
@@ -1,4 +1,5 @@
 /// <reference types="vite/client" />
+/// <reference types="@testing-library/jest-dom" />
 
 interface ImportMetaEnv {
   readonly VITE_GITHUB_TOKEN: string;
diff --git a/vite.config.ts b/vite.config.ts
index 0e77097..80a6bac 100644
--- a/vite.config.ts
+++ b/vite.config.ts
@@ -1,4 +1,4 @@
-import { defineConfig } from 'vite';
+import { defineConfig } from 'vitest/config';
 import react from '@vitejs/plugin-react';
 import tailwindcss from '@tailwindcss/vite';
 import path from 'path';
@@ -14,4 +14,9 @@ export default defineConfig({
     port: 5173,
     open: true,
   },
+  test: {
+    environment: 'jsdom',
+    setupFiles: ['./src/test/setup.ts'],
+    globals: true,
+  },
 });