57 lines
1.4 KiB
Markdown
57 lines
1.4 KiB
Markdown
# Service Fallback & Graceful Degradation Tests
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Tests EU-Utility's ability to handle service unavailability gracefully.
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## Test Categories
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### Network Failures
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- DNS resolution failures
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- Connection refused
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- Network unreachable
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- Service timeouts
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### Missing Dependencies
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- OCR engines not installed
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- requests library missing
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- paho-mqtt not available
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- Optional libraries
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### API Errors
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- Rate limiting (429)
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- Authentication failures (401/403)
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- Server errors (500/503)
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- Invalid responses
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### Timeout Handling
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- Request timeouts
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- Slow responses
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- Hanging connections
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- Retry logic
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## Expected Graceful Degradation
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### When Network Fails
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- Show cached data if available
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- Display clear error message
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- Retry with exponential backoff
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- Never block UI indefinitely
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### When Dependencies Missing
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- Disable affected features
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- Show informative messages
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- Provide alternatives
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- Continue with reduced functionality
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### When API Errors
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- Handle specific error codes
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- Implement appropriate retry logic
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- Show user-friendly messages
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- Log for debugging
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## Recovery Mechanisms
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1. **Automatic Retry**: Exponential backoff for transient failures
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2. **Cached Data**: Use stale cache when fresh data unavailable
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3. **Feature Degradation**: Disable features that depend on unavailable services
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4. **User Notification**: Clear messages about service status
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5. **Reconnection**: Detect when service returns and resume normal operation |