python data_error ai_generated true

sqlalchemy.exc.IntegrityError: (psycopg2.errors.UniqueViolation) duplicate key value violates unique constraint "users_email_key"

ID: python/pytest-sqlalchemy-fixture-rollback

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80%Fix Rate
85%Confidence
0Evidence
2025-11-10First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
3.x active — — —

Root Cause

The database fixture does not roll back transactions between tests, causing data from previous tests to persist.

generic

中文

数据库 fixture 未在测试之间回滚事务，导致先前测试的数据持久化。

Workarounds

  1. 95% success 
    @pytest.fixture(scope='function')
def db_session():
    connection = engine.connect()
    transaction = connection.begin()
    session = Session(bind=connection)
    yield session
    session.close()
    transaction.rollback()
    connection.close()
  2. 90% success 
    Use pytest-sqlalchemy's fixtures or factory_boy with a session that rolls back after each test.

Dead Ends

Common approaches that don't work:

  1. 70% fail

    This is a workaround that does not fix the underlying state leakage and may lead to other issues.

  2. 80% fail

    This is slow and may not be feasible for large test suites.