import unittest2 as unittest

from celery import backends
from celery.backends.amqp import AMQPBackend
from celery.backends.pyredis import RedisBackend


class TestBackends(unittest.TestCase):

    def test_get_backend_aliases(self):
        expects = [("amqp", AMQPBackend),
                   ("redis", RedisBackend)]
        for expect_name, expect_cls in expects:
            self.assertIsInstance(backends.get_backend_cls(expect_name)(),
                                  expect_cls)

    def test_get_backend_cahe(self):
        backends._backend_cache = {}
        backends.get_backend_cls("amqp")
        self.assertIn("amqp", backends._backend_cache)
        amqp_backend = backends.get_backend_cls("amqp")
        self.assertIs(amqp_backend, backends._backend_cache["amqp"])

import unittest2 as unittest

from celery import backends
from celery.backends.amqp import AMQPBackend
from celery.backends.database import DatabaseBackend


class TestBackends(unittest.TestCase):

    def test_get_backend_aliases(self):
        expects = [("amqp", AMQPBackend),
                   ("database", DatabaseBackend)]
        for expect_name, expect_cls in expects:
            self.assertIsInstance(backends.get_backend_cls(expect_name)(),
                                  expect_cls)

    def test_get_backend_cahe(self):
        backends._backend_cache = {}
        backends.get_backend_cls("amqp")
        self.assertIn("amqp", backends._backend_cache)
        amqp_backend = backends.get_backend_cls("amqp")
        self.assertIs(amqp_backend, backends._backend_cache["amqp"])

Test using DatabaseBackend instead of RedisBackend, as the latter requires the redis module to be installed.
tests.backends: Test using DatabaseBackend instead of RedisBackend, as the latter requires the redis module to be installed.

  import unittest2 as unittest
  
  from celery import backends
  from celery.backends.amqp import AMQPBackend
- from celery.backends.pyredis import RedisBackend
+ from celery.backends.database import DatabaseBackend
  
  
  class TestBackends(unittest.TestCase):
  
      def test_get_backend_aliases(self):
          expects = [("amqp", AMQPBackend),
-                    ("redis", RedisBackend)]
+                    ("database", DatabaseBackend)]
          for expect_name, expect_cls in expects:
              self.assertIsInstance(backends.get_backend_cls(expect_name)(),
                                    expect_cls)
  
      def test_get_backend_cahe(self):
          backends._backend_cache = {}
          backends.get_backend_cls("amqp")
          self.assertIn("amqp", backends._backend_cache)
          amqp_backend = backends.get_backend_cls("amqp")
          self.assertIs(amqp_backend, backends._backend_cache["amqp"])
  
Test using DatabaseBackend instead of RedisBackend, as the latter requires the redis module to be installed.
## Code Before:
import unittest2 as unittest

from celery import backends
from celery.backends.amqp import AMQPBackend
from celery.backends.pyredis import RedisBackend


class TestBackends(unittest.TestCase):

    def test_get_backend_aliases(self):
        expects = [("amqp", AMQPBackend),
                   ("redis", RedisBackend)]
        for expect_name, expect_cls in expects:
            self.assertIsInstance(backends.get_backend_cls(expect_name)(),
                                  expect_cls)

    def test_get_backend_cahe(self):
        backends._backend_cache = {}
        backends.get_backend_cls("amqp")
        self.assertIn("amqp", backends._backend_cache)
        amqp_backend = backends.get_backend_cls("amqp")
        self.assertIs(amqp_backend, backends._backend_cache["amqp"])

## Instruction:
Test using DatabaseBackend instead of RedisBackend, as the latter requires the redis module to be installed.
## Code After:
import unittest2 as unittest

from celery import backends
from celery.backends.amqp import AMQPBackend
from celery.backends.database import DatabaseBackend


class TestBackends(unittest.TestCase):

    def test_get_backend_aliases(self):
        expects = [("amqp", AMQPBackend),
                   ("database", DatabaseBackend)]
        for expect_name, expect_cls in expects:
            self.assertIsInstance(backends.get_backend_cls(expect_name)(),
                                  expect_cls)

    def test_get_backend_cahe(self):
        backends._backend_cache = {}
        backends.get_backend_cls("amqp")
        self.assertIn("amqp", backends._backend_cache)
        amqp_backend = backends.get_backend_cls("amqp")
        self.assertIs(amqp_backend, backends._backend_cache["amqp"])
