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Compatibility Testing

Compatibility Testing is the process of verifying that a software application works correctly across different environments, such as browsers, operating systems, devices, screen resolutions, and configurations.

Compatibility testing answers: “Does the application behave consistently in different environments?”

1. Definition

Compatibility Testing is the process of verifying that a software application works correctly across different environments, such as browsers, operating systems, devices, screen resolutions, and configurations.

Compatibility testing answers: “Does the application behave consistently in different environments?”

2. Purpose of Compatibility Testing

  • Ensure consistent user experience across platforms
  • Identify environment-specific defects
  • Reduce customer complaints due to environment issues
  • Validate broader user reach

3. Types of Compatibility Testing (Manual Focus)

3.1 Browser Compatibility Testing

  • Chrome, Firefox, Edge, Safari
  • UI rendering consistency
  • JavaScript and CSS behavior

3.2 Operating System Compatibility Testing

  • Windows, macOS, Linux
  • OS-specific behavior and permissions

3.3 Device Compatibility Testing

  • Desktop, tablet, mobile
  • Different screen sizes and resolutions

3.4 Resolution Compatibility Testing

  • Different screen resolutions
  • Responsive layout behavior
  • Text and image alignment

3.5 Network Compatibility Testing

  • Different network speeds
  • Wi-Fi vs mobile data
  • Offline/poor network handling

4. Manual Tester’s Role

  • Identify target environments
  • Execute key scenarios across environments
  • Validate UI, functionality, and performance perception
  • Report environment-specific issues

5. Compatibility Testing Scope

Includes:

  • Layout and alignment
  • Font and color consistency
  • Navigation behavior
  • File downloads/uploads
  • Error handling differences

6. Compatibility Testing vs Cross-Browser Testing

Aspect Compatibility Testing Cross-Browser Testing
Scope Multiple environments Browsers only
Focus Overall behavior Browser behavior
Coverage Wide Narrow

7. Real-Time Example

An application works fine on Chrome but:

  • Button overlaps text on Safari
  • Dropdown doesn’t open on Firefox

Compatibility testing detects these issues.

8. Entry & Exit Criteria

Entry Criteria

  • Stable build available
  • Supported environments defined

Exit Criteria

  • Critical environment issues resolved
  • Known limitations documented

9. Common Compatibility Defects

  • UI distortion
  • Broken functionality on specific browsers
  • Font rendering issues
  • Device-specific crashes

10. Common Mistakes

  • Testing only on one browser
  • Ignoring resolution differences
  • Assuming “works on my machine”

11. Interview-Ready Answers

Short answer:

Compatibility testing ensures that a software application works correctly across different browsers, devices, operating systems, and environments.

Detailed answer:

Compatibility testing validates consistent behavior and user experience of an application across multiple environments to ensure broad usability.

12. Key Takeaway

Compatibility Testing ensures all users get a consistent and reliable experience, regardless of their environment.