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System design patterns

Sharding, load balancing, CAP tradeoffs, and scaling patterns — interview and production ready.

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How to Mock a Timeout per Dependency Call in Python

This code demonstrates how to simulate and test per-call timeouts for external dependencies using Python's unittest.mock and a simple timing wrapper.

mock timeout unittest
Python 
```python
import time
from unittest.mock import Mock, patch

def call_dependency(dependency, timeout):
    start = time.time()
    result = dependency.call()
    elapsed = time.time() - start
    if elapsed > timeout:
        raise TimeoutError(f"Dependency call took {elapsed:.2f}s, exceeding timeout {timeout}s")
    …
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