python config_error ai_generated true

ScopeMismatch: 你尝试用 session 作用域的请求对象访问 function 作用域的 fixture db

ScopeMismatch: You tried to access the function scoped fixture db with a session scoped request object

ID: python/pytest-scope-mismatch-function-vs-session

其他格式: JSON · Markdown 中文 · English
80%修复率
88%置信度
0证据数
2024-04-22首次发现

版本兼容性

版本状态引入弃用备注
7.x active — — —
8.x active — — —

根因分析

session 作用域的 fixture 依赖了 function 作用域的 fixture，这是不允许的，因为 function 作用域的 fixture 在每个测试后就会销毁，而 session fixture 存活更久。

English

A session-scoped fixture depends on a function-scoped fixture, which is not allowed because the function-scoped fixture is torn down after each test while the session fixture lives longer.

generic

解决方案

  1. 90% 成功率 
    @pytest.fixture(scope='session')
def db():
    conn = connect()
    yield conn
    conn.close()

@pytest.fixture(scope='session')
def seeded_db(db):
    seed(db)
    return db
  2. 92% 成功率 
    @pytest.fixture(scope='session')
def db():
    conn = connect()
    yield conn
    conn.close()

@pytest.fixture
def user(db):
    u = create_user(db)
    yield u
    db.delete(u)

无效尝试

常见但无效的做法:

  1. 30% 失败

    Fixes the error but destroys the performance benefit; the expensive setup runs for every test.

  2. 50% 失败

    Defaults to function scope, same performance regression, and may not match other fixtures that already use session.