List scenarios which we cannot automate using Selenium WebDriver.

Selenium WebDriver, despite being a powerful browser automation tool, has specific limitations:

1. Bitmap/Image Comparison Selenium cannot compare screenshots pixel-by-pixel or validate visual appearance.

Cannot check: "Does this button look exactly like in the design spec?"
Workaround: Applitools Eyes, Percy.io, Sikuli for visual testing

2. CAPTCHA (Completely Automated Public Turing Test) CAPTCHA is specifically designed to prevent bots — Selenium cannot solve it.

Cannot automate: reCAPTCHA, image CAPTCHAs, puzzle CAPTCHAs
Workaround: Disable in test environment, use test bypass tokens

3. Barcode Reading Selenium cannot decode barcodes or QR codes from images on the page.

Cannot read: Product barcodes, QR codes displayed in browser
Workaround: Zxing library for standalone barcode decoding

4. Windows OS-Level Pop-ups Native Windows dialogs (file upload/download, Windows Security) are outside browser control.

Cannot handle: Windows file dialog, Windows Security popup
Workaround: AutoIT, Sikuli, Robot class (Java), browser profile settings

5. Third-Party Calendar / Date Picker Widgets Flash-based or JS widgets that are heavily obfuscated.

Cannot interact with: Flash datepickers, some JavaScript calendar libraries
Workaround: JavascriptExecutor to set date field value directly

6. Image Files Reading text from images, verifying visual content of images.

Cannot verify: Image content, OCR on images
Workaround: Tesseract OCR for image text recognition

7. Word Documents and PDFs Browser displays them as embedded viewers — content not accessible via DOM.

Cannot read: Text in PDF/Word files embedded in browser
Workaround: Apache POI (Word), Apache PDFBox (PDF), download and parse

8. Biometric Authentication Fingerprint, Face ID, Touch ID — requires physical hardware interaction.

Complete list:

1. ✓Bitmap comparison — not possible with Selenium WebDriver
2. ✓CAPTCHA — not possible with Selenium WebDriver
3. ✓Barcode reading — not possible with Selenium WebDriver
4. ✓Windows OS-based pop-ups — requires AutoIT/Sikuli
5. ✓Third-party calendars/elements — use JS workaround
6. ✓Image content reading — requires OCR tools
7. ✓Word/PDF processing — requires Apache POI/PDFBox

Best practice: For each limitation, identify a complementary tool:

• ✓Visual testing → Applitools
• ✓Native dialogs → AutoIT
• ✓Document reading → Apache POI / PDFBox
• ✓CAPTCHA bypass → Test environment configuration