"""Unit tests for the Mongo backend"""
from __future__ import absolute_import

from unittest import TestCase
from mock import patch
from mock import sentinel

from pymongo.errors import PyMongoError
from bson.errors import BSONError

from eventtracking.backends.mongodb import MongoBackend


class TestMongoBackend(TestCase):
    """Unit tests for the Mongo backend"""

    def setUp(self):
        super(TestMongoBackend, self).setUp()
        self.mongo_patcher = patch('eventtracking.backends.mongodb.MongoClient')
        self.addCleanup(self.mongo_patcher.stop)
        self.mongo_patcher.start()

        self.backend = MongoBackend()

    def test_mongo_backend(self):
        events = [{'test': 1}, {'test': 2}]

        self.backend.send(events[0])
        self.backend.send(events[1])

        # Check if we inserted events into the database

        calls = self.backend.collection.insert.mock_calls

        self.assertEqual(len(calls), 2)

        # Unpack the arguments and check if the events were used
        # as the first argument to collection.insert

        def first_argument(call):
            """Extract the first argument from a `mock.call`"""
            _, args, _ = call
            return args[0]

        self.assertEqual(events[0], first_argument(calls[0]))
        self.assertEqual(events[1], first_argument(calls[1]))

    def test_authentication_settings(self):
        backend = MongoBackend(user=sentinel.user, password=sentinel.password)
        backend.database.authenticate.assert_called_once_with(sentinel.user, sentinel.password)

    def test_mongo_pymongo_insertion_error(self):
        self.backend.collection.insert.side_effect = PyMongoError

        self.backend.send({'test': 1})
        # Ensure this error is caught

    def test_mongo_bson_insertion_error(self):
        self.backend.collection.insert.side_effect = BSONError

        self.backend.send({'test': 1})
        # Ensure this error is caught
