team-tryouts/tests/test_role_change.py

"""Changing a user's role — ARCH-008.

`role` is the polymorphic discriminator, and SQLAlchemy fixes an instance's
class at load time. edit_user therefore writes the column with a
statement-level UPDATE and re-reads the row, which is correct. What it did
next was not: it called db.session.remove(), throwing away the whole
session, and it committed the role on its own before the rest of the edit
had been applied.

The two consequences these tests pin down:

  - everything the request still held became detached, current_user
    included. The route only survived because it had copied the actor's
    name and id into locals beforehand — a workaround, in place of the fix.
  - the role change was already committed when the rest of the edit ran, so
    a failure afterwards left the account promoted and nothing else
    applied.
"""

import pytest

from app.extensions import db
from app.models import Coach, Player, User


def _edit(client, user_id, **overrides):
    payload = {
        'full_name': 'Promoted Person',
        'email': '[email protected]',
        'role': 'coach',
        'is_active_account': 'on',
    }
    payload.update(overrides)
    return client.post(f'/users/{user_id}/edit', data=payload, follow_redirects=True)


class TestPolymorphicIdentity:
    def test_the_account_takes_its_new_class(self, app, client, as_role, make_user):
        target_id = make_user('player')
        as_role('admin')

        _edit(client, target_id)

        with app.app_context():
            assert isinstance(db.session.get(User, target_id), Coach)

    def test_the_new_role_grants_its_pages_right_away(
        self, app, client, as_role, make_user, login
    ):
        """isinstance() is how this application authorises; a stale class in
        the identity map is a stale permission set."""
        target_id = make_user('player')
        as_role('admin')
        _edit(client, target_id)

        with app.app_context():
            username = db.session.get(User, target_id).username
        client.post('/auth/logout')
        login(username)

        # Coach-only, and it is a coach's own page rather than a redirect.
        assert client.get('/users/notes-dashboard').status_code == 200

    def test_the_other_fields_of_the_edit_land_too(
        self, app, client, as_role, make_user
    ):
        target_id = make_user('player')
        as_role('admin')

        _edit(client, target_id, full_name='Renamed Too', phone='555-0100')

        with app.app_context():
            user = db.session.get(User, target_id)
            assert user.full_name == 'Renamed Too'
            assert user.phone == '555-0100'


class TestTheActingPresident:
    """db.session.remove() detached current_user mid-request."""

    def test_the_president_keeps_their_session(self, client, as_role, make_user):
        target_id = make_user('player')
        as_role('admin')

        _edit(client, target_id)

        assert client.get('/users').status_code == 200

    def test_the_response_renders(self, client, as_role, make_user):
        target_id = make_user('player')
        as_role('admin')

        response = _edit(client, target_id)

        assert response.status_code == 200


class TestAtomicity:
    def test_a_failure_after_the_update_leaves_the_role_alone(
        self, app, client, as_role, make_user, monkeypatch
    ):
        """The role used to be committed on its own, before the rest of the
        edit ran. A failure afterwards left an account promoted, and no
        interface reported it."""
        target_id = make_user('player')
        as_role('admin')

        def _explode(user, selected_games):
            raise RuntimeError('storage unavailable')

        monkeypatch.setattr('app.routes.users.update_user_gamertags', _explode)

        with pytest.raises(RuntimeError):
            _edit(client, target_id)

        with app.app_context():
            user = db.session.get(User, target_id)
            assert isinstance(user, Player)
            assert user.role == 'player'