Python Testing with pytest, Second Edition: Typing mistake (page 13)

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In the Card class definition, the type hints for the summary, owner, and id attributes are currently specified as str, str, and int respectively, with default values of None.

@dataclass class Card: owner: str = None summary: str = None state: str = "todo" id: int = field(default=None, compare=False)

This is a minor mistake. To accurately reflect that these fields are optional and can be None, they should be defined using Optional from the typing module. The corrected type hints are:

  • owner should be Optional[str]
  • summary should be Optional[str]
  • id should be Optional[int]

The corrected class definition would appear as follows (assuming from typing import Optional is present):

from typing import Optional @dataclass class Card: owner: Optional[str] = None summary: Optional[str] = None state: str = "todo" id: Optional[int] = field(default=None, compare=False)