new_contents: import unittest
  from cla_public.apps.base.views import set_locale
  
  from cla_public.app import create_app
  from flask import request
  
  class LocaleTest(unittest.TestCase):
  
    def setUp(self):
      self.app = create_app('config/testing.py')
      ctx = self.app.test_request_context()
      ctx.push()
      self.client = self.app.test_client()
  
    def test_locale_cookie_is_set(self):
      with self.app.test_client() as client:
        response = client.get('/?locale=en_GB')
        self.check_cookie(response, 'locale', 'en_GB')
        
    def check_cookie(self, response, name, value):
      # Checks for existence of a cookie and verifies the value of it.
      from werkzeug.http import parse_cookie
      cookies = response.headers.getlist('Set-Cookie')
      for cookie in cookies:
          c_key, c_value = parse_cookie(cookie).items()[0]
          if c_key == name:
              assert c_value == value
              return
      # Cookie not found
      assert False
  
subject: Test locale is set based on query param