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?

Strange ... indeed. Have you try to use self.assertRaises within a with statement, has outlined in the documentation? https://docs.python.org/2/library/unittest.html — ohe, Dec 21 '15 at 21:31
Are you sure you have `db.session.commit` and not `db.session.commit()`? — alecxe, Dec 21 '15 at 21:32
Related or duplicate: http://stackoverflow.com/q/19289291/771848. — alecxe, Dec 21 '15 at 21:32
Yes I have tried using the with statement, with the same failure. And yes I am sure I have db.session.commit without () — allenlin1992, Dec 21 '15 at 21:35

score 8 · Accepted Answer · answered Dec 21 '15 at 21:46

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)

assertRaises not catching IntegrityError , Flask SQLAlchemy

1 Answers1