# This file is part of Tryton.  The COPYRIGHT file at the top level of
# this repository contains the full copyright notices and license terms.
import unittest
from trytond.tests.test_tryton import DB_NAME, USER, CONTEXT, install_module
from trytond.transaction import Transaction


def empty_transaction(*args, **kwargs):
    '''
    Just starts a transaction in the context manager and returns `True`
    and stops transaction for the given arguments.

    All positional arguments are passed to `start` method of transaction
    '''
    with Transaction().start(*args, **kwargs):
        return True


class TransactionTestCase(unittest.TestCase):
    'Test the Transaction Context manager'

    @classmethod
    def setUpClass(cls):
        install_module('tests')

    def test_nonexistdb(self):
        '''Attempt opening a transaction with a non existant DB
        and ensure that it stops cleanly and allows starting of next
        transaction'''
        self.assertRaises(
            Exception, empty_transaction, "Non existant DB", USER,
            context=CONTEXT)
        self.assertTrue(empty_transaction(DB_NAME, USER, context=CONTEXT))

    def test_set_user(self):
        'Test set_user'
        with Transaction().start(DB_NAME, USER, context=CONTEXT) \
                as transaction:
            self.assertEqual(transaction.user, USER)
            self.assertEqual(transaction.context.get('user'), None)

            with Transaction().set_user(0):
                self.assertEqual(transaction.user, 0)
                self.assertEqual(transaction.context.get('user'), None)

            with Transaction().set_user(0, set_context=True):
                self.assertEqual(transaction.user, 0)
                self.assertEqual(transaction.context.get('user'), USER)

                # Nested same set_user should keep original context user
                with Transaction().set_user(0, set_context=True):
                    self.assertEqual(transaction.user, 0)
                    self.assertEqual(transaction.context.get('user'), USER)

                # Unset user context
                with Transaction().set_user(0, set_context=False):
                    self.assertEqual(transaction.user, 0)
                    self.assertEqual(transaction.context.get('user'), None)

            # set context for non root
            self.assertRaises(ValueError,
                Transaction().set_user, 2, set_context=True)

            # not set context for non root
            with Transaction().set_user(2):
                self.assertEqual(transaction.user, 2)

    def test_stacked_transactions(self):
        'Test that transactions are stacked / unstacked correctly'
        with Transaction().start(DB_NAME, USER, context=CONTEXT) \
                as transaction:
            with transaction.new_transaction() as new_transaction:
                self.assertIsNot(new_transaction, transaction)
                self.assertIsNot(Transaction(), transaction)
                self.assertIs(Transaction(), new_transaction)
            self.assertIs(Transaction(), transaction)


def suite():
    return unittest.TestLoader().loadTestsFromTestCase(TransactionTestCase)