assertRaises not catching IntegrityError , Flask SQLAlchemy

Question

My test is not catching psycopg2.IntegrityError with assertRaises. I am using Flask-SQLAlchemy.

def test_insert_cash_flow(self):
    cf = CashFlow()
    db.session.add(cf)
    self.assertRaises(psycopg2.IntegrityError, db.session.commit)

My CashFlow SQLAlchemy model has several nullable=False fields. It says my tests failed and IntegrityError is printed to the screen but my assertRaises does not catch this. Does anyone have any suspicion why?

Answer 1

SQLAlchemy raises sqlalchemy.exc.IntegrityError, which wraps the underlying exception, not the exception from the database driver.

sqlalchemy.exc.IntegrityError: (sqlite3.IntegrityError) NOT NULL constraint failed: user.name [SQL: 'INSERT INTO user (name) VALUES (?)'] [parameters: (None,)]

Test for the correct exception.

from sqlalchemy.exc import IntegrityError
self.assertRaises(IntegrityError, db.session.commit)