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Testing & modern typing

pytest basics, mocks, type hints, TypedDict, Protocol, and static-checking patterns.

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Testing & modern typing easy

Interface Segregation with Fake Test Implementations in Python

Defines segregated abstract interfaces (Printer, Scanner) and uses a FakePrinter to record calls for unit testing without real resources.

abc interface-segregation testing
Python 
from abc import ABC, abstractmethod


class Printer(ABC):
    @abstractmethod
    def print_document(self, doc: str) -> str:
        pass


class Scanner(ABC):
    @abstractmethod
    def scan_document(self) -> str:
        pass


class MultiFunctionPrinter(Printer, Scanner):
    def print_document(self, doc: str) -> …
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