test(auth): add unit and e2e tests for auto-redirect

- Unit tests for redirect URL construction and preservation
- E2E tests for unauthenticated redirect flow and authenticated redirect

Amp-Thread-ID: https://ampcode.com/threads/T-019c17af-6967-74be-8e42-6191059b8d63
Co-authored-by: Amp <amp@ampcode.com>

Author: zainfathoni

app/services/__tests__/auth.server.test.ts

@@ -0,0 +1,79 @@
+import { describe, it, expect } from 'vitest'
+
+describe('Auth redirect URL construction', () => {
+  it('should construct correct login URL with redirectTo param from pathname', () => {
+    const request = new Request('http://localhost:3000/dashboard/courses')
+    const redirectTo = new URL(request.url).pathname
+
+    const searchParams = new URLSearchParams([['redirectTo', redirectTo]])
+    const loginUrl = `/login?${searchParams}`
+
+    expect(loginUrl).toBe('/login?redirectTo=%2Fdashboard%2Fcourses')
+  })
+
+  it('should use custom redirectTo when provided', () => {
+    const redirectTo = '/custom/path'
+
+    const searchParams = new URLSearchParams([['redirectTo', redirectTo]])
+    const loginUrl = `/login?${searchParams}`
+
+    expect(loginUrl).toBe('/login?redirectTo=%2Fcustom%2Fpath')
+  })
+
+  it('should handle root path', () => {
+    const request = new Request('http://localhost:3000/')
+    const redirectTo = new URL(request.url).pathname
+
+    const searchParams = new URLSearchParams([['redirectTo', redirectTo]])
+    const loginUrl = `/login?${searchParams}`
+
+    expect(loginUrl).toBe('/login?redirectTo=%2F')
+  })
+
+  it('should handle paths with query parameters', () => {
+    const redirectTo = '/dashboard/courses?filter=active'
+
+    const searchParams = new URLSearchParams([['redirectTo', redirectTo]])
+    const loginUrl = `/login?${searchParams}`
+
+    expect(loginUrl).toContain('redirectTo=')
+    expect(decodeURIComponent(loginUrl)).toContain(
+      '/dashboard/courses?filter=active'
+    )
+  })
+})
+
+describe('Login redirect URL preservation', () => {
+  it('should extract redirectTo from URL search params', () => {
+    const url = new URL(
+      'http://localhost:3000/login?redirectTo=/dashboard/profile'
+    )
+    const redirectTo = url.searchParams.get('redirectTo') ?? '/dashboard'
+
+    expect(redirectTo).toBe('/dashboard/profile')
+  })
+
+  it('should default to /dashboard when redirectTo is not provided', () => {
+    const url = new URL('http://localhost:3000/login')
+    const redirectTo = url.searchParams.get('redirectTo') ?? '/dashboard'
+
+    expect(redirectTo).toBe('/dashboard')
+  })
+
+  it('should preserve redirectTo in success/failure redirects', () => {
+    const redirectTo = '/dashboard/transactions'
+    const successRedirect = `/login?redirectTo=${encodeURIComponent(
+      redirectTo
+    )}`
+    const failureRedirect = `/login?redirectTo=${encodeURIComponent(
+      redirectTo
+    )}`
+
+    expect(successRedirect).toBe(
+      '/login?redirectTo=%2Fdashboard%2Ftransactions'
+    )
+    expect(failureRedirect).toBe(
+      '/login?redirectTo=%2Fdashboard%2Ftransactions'
+    )
+  })
+})

e2e/auth-redirect.spec.ts

@@ -0,0 +1,58 @@
+import { test, expect } from './base-test'
+import { authFixtures } from './fixtures'
+
+test.describe('Auto-redirect after authentication', () => {
+  test.describe('Unauthenticated user', () => {
+    test.use({
+      storageState: authFixtures.public,
+    })
+
+    test('redirects to login with redirectTo param when accessing protected route', async ({
+      page,
+    }) => {
+      await page.goto('/dashboard/profile/edit')
+
+      await page.waitForURL('**/login**')
+      const url = new URL(page.url())
+      expect(url.pathname).toBe('/login')
+      expect(url.searchParams.get('redirectTo')).toBe('/dashboard/profile/edit')
+    })
+
+    test('login page preserves redirectTo in form action URL', async ({
+      page,
+    }) => {
+      await page.goto('/login?redirectTo=/dashboard/transactions')
+
+      await expect(page.getByText('Masuk ke akun Anda')).toBeVisible()
+
+      const currentUrl = new URL(page.url())
+      expect(currentUrl.searchParams.get('redirectTo')).toBe(
+        '/dashboard/transactions'
+      )
+    })
+  })
+
+  test.describe('Authenticated user', () => {
+    test.use({
+      storageState: authFixtures.member,
+    })
+
+    test('login page redirects to redirectTo param if already authenticated', async ({
+      page,
+    }) => {
+      await page.goto('/login?redirectTo=/dashboard/profile/edit')
+
+      await page.waitForURL('**/dashboard/profile/edit')
+      expect(page.url()).toContain('/dashboard/profile/edit')
+    })
+
+    test('login page redirects to dashboard by default if already authenticated', async ({
+      page,
+    }) => {
+      await page.goto('/login')
+
+      await page.waitForURL('**/dashboard')
+      expect(page.url()).toContain('/dashboard')
+    })
+  })
+})