post_clear_check/code/post_clear_check/tests/fakes.py

"""不连数据库的连接替身。"""


class FakeCursor:
    """记录语句，并按连接上的标志返回只读探针结果。"""

    def __init__(self, connection: "FakeConnection") -> None:
        self._connection = connection

    async def __aenter__(self) -> "FakeCursor":
        return self

    async def __aexit__(self, exc_type: object, exc: object, tb: object) -> bool:
        return False

    async def execute(self, query: str, args: object = None) -> None:
        self._connection.statements.append(query)

    async def fetchall(self) -> list[tuple[object, ...]]:
        return [(self._connection.readonly_flag,)]

    @property
    def description(self) -> tuple[tuple[str], ...]:
        return (("value",),)


class FakeConnection:
    """业务连接或自有库连接的替身。"""

    def __init__(self, readonly_flag: object = 1) -> None:
        self.readonly_flag = readonly_flag
        self.statements: list[str] = []
        self.cursor_calls = 0
        self.closed = False

    def cursor(self) -> FakeCursor:
        self.cursor_calls += 1
        return FakeCursor(self)

    async def ensure_closed(self) -> None:
        self.closed = True


class RejectingConnection:
    """游标一旦创建就失败，用来证明语句没有发给驱动。"""

    def __init__(self) -> None:
        self.cursor_calls = 0

    def cursor(self) -> FakeCursor:
        self.cursor_calls += 1
        raise AssertionError("不应向数据库发送语句")