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System design patterns

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

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System design patterns easy

How to Mock Hexagonal Architecture Ports and Adapters in Python

Mock an email adapter in a hexagonal architecture with unittest.mock to test business logic in isolation.

hexagonal-architecture unittest-mock dependency-injection
Python 
from unittest.mock import Mock

class EmailService:
    def send(self, recipient, message):
        raise NotImplementedError

class OrderProcessor:
    def __init__(self, email_service):
        self.email_service = email_service
    
    def process_order(self, order_id, customer_email):
        # Business logic
   …
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