diff --git a/src/components/user/theme-picker.cy.tsx b/src/components/user/theme-picker.cy.tsx
new file mode 100644
index 0000000..23dc01b
--- /dev/null
+++ b/src/components/user/theme-picker.cy.tsx
@@ -0,0 +1,41 @@
+import React from 'react';
+import { ThemePicker } from '@/components/user/theme-picker';
+import { ThemeProvider } from '../theme-provider';
+
+describe('<ThemePicker />', () => {
+  it('renders', () => {
+    cy.mount(<ThemePicker />);
+  });
+
+  it('toggle open and close', () => {
+    cy.mount(<ThemePicker />);
+    cy.getBySel('theme-picker').click();
+    cy.getBySel('theme-picker-content').should('exist');
+    cy.get('html').click();
+    cy.getBySel('theme-picker-content').should('not.exist');
+  });
+
+  it('enable dark mode', () => {
+    cy.mount(
+      <ThemeProvider>
+        <ThemePicker />
+      </ThemeProvider>,
+    );
+
+    cy.getBySel('theme-picker').click();
+    cy.getBySel('dark-theme').click();
+    cy.get('html').should('have.attr', 'data-theme', 'dark');
+  });
+
+  it('enable light mode', () => {
+    cy.mount(
+      <ThemeProvider>
+        <ThemePicker />
+      </ThemeProvider>,
+    );
+
+    cy.getBySel('theme-picker').click();
+    cy.getBySel('light-theme').click();
+    cy.get('html').should('have.attr', 'data-theme', 'light');
+  });
+});
diff --git a/src/components/user/theme-picker.tsx b/src/components/user/theme-picker.tsx
index 5341c3c..3ceca4c 100644
--- a/src/components/user/theme-picker.tsx
+++ b/src/components/user/theme-picker.tsx
@@ -18,20 +18,26 @@ export function ThemePicker() {
   return (
     <DropdownMenu>
       <DropdownMenuTrigger asChild>
-        <Button variant='outline' size='icon'>
+        <Button variant='outline' size='icon' data-cy='theme-picker'>
           <Sun className='h-[1.2rem] w-[1.2rem] rotate-0 scale-100 transition-all dark:-rotate-90 dark:scale-0' />
           <Moon className='absolute h-[1.2rem] w-[1.2rem] rotate-90 scale-0 transition-all dark:rotate-0 dark:scale-100' />
           <span className='sr-only'>Toggle theme</span>
         </Button>
       </DropdownMenuTrigger>
-      <DropdownMenuContent align='end'>
-        <DropdownMenuItem onClick={() => setTheme('light')}>
+      <DropdownMenuContent align='end' data-cy='theme-picker-content'>
+        <DropdownMenuItem
+          onClick={() => setTheme('light')}
+          data-cy='light-theme'
+        >
           Light
         </DropdownMenuItem>
-        <DropdownMenuItem onClick={() => setTheme('dark')}>
+        <DropdownMenuItem onClick={() => setTheme('dark')} data-cy='dark-theme'>
           Dark
         </DropdownMenuItem>
-        <DropdownMenuItem onClick={() => setTheme('system')}>
+        <DropdownMenuItem
+          onClick={() => setTheme('system')}
+          data-cy='system-theme'
+        >
           System
         </DropdownMenuItem>
       </DropdownMenuContent>