techaiprojectpython

name	TechAIProjectPython
description	Create or modify Python application components using DDD boundaries, early returns, and deterministic pytest coverage.

Python Project Skill

When to use

• Services, use cases, adapters, repositories, and domain modules in Python applications.
• Refactoring or extending existing Python application components.
• Non-script Python code that contains domain behavior.

Mandatory rules

• Apply DDD boundaries: domain, application, and infrastructure concerns must be separated.
• Keep business rules in domain entities/value objects/domain services.
• Keep I/O and SDK clients in infrastructure adapters.
• Use ubiquitous language in domain classes, methods, and exceptions.
• Prefer early return and guard clauses.
• Keep code explicit and readability-first.
• Add unit tests for testable logic.

Testing

• Use pytest.
• Keep tests deterministic and isolated.
• Prefer BDD-like names in the given_when_then style.
• For modify tasks with existing tests: edit implementation first, run existing tests, then update tests only for intentional behavior changes.

Minimal module example

"""Purpose: Resolve account status based on domain rules."""

from dataclasses import dataclass


@dataclass(frozen=True)
class AccountId:
    value: str

    def __post_init__(self) -> None:
        if not self.value.strip():
            raise ValueError("account id is required")


def resolve_account_state(account_id: AccountId, is_locked: bool) -> str:
    if is_locked:
        return "locked"
    return f"active:{account_id.value}"

Minimal test example

import pytest


def test_given_blank_account_id_when_creating_then_raises_value_error() -> None:
    with pytest.raises(ValueError):
        AccountId(" ")