Fix #21 Set chrome accept_languages in headless mode

In #21 i found a bug in chrome driver:
https://bugs.chromium.org/p/chromedriver/issues/detail?id=3358

Add a work-a-round for this, by set LANG/LANGUAGE environment variables.
btw. `env` argument has a wrong type annotation in upstream, see:
SeleniumHQ/selenium#10072

.github/workflows/pythonapp.yml

@@ -29,7 +29,9 @@ jobs:
 
     - name: Install Selenium requirements
       run: |
-        sudo apt install google-chrome-stable firefox
+        sudo apt install google-chrome-stable chromium-chromedriver firefox firefox-geckodriver
+        chromedriver -version
+        geckodriver --version
 
     - name: 'Install package'
       run: |

README.creole

@@ -745,7 +745,7 @@ Using the old place {{{django_tools.unittest_utils.selenium_utils}}} still works
 == Django compatibility
 
 |= django-tools    |= django version |= python         |
-| >= v0.49.0.rc1   | 2.2, 3.1, 3.2   | 3.7, 3.8, 3.9   |
+| >= v0.49.0.rc2   | 2.2, 3.1, 3.2   | 3.7, 3.8, 3.9   |
 | >= v0.47.0       | 2.2, 3.0, 3.1   | >= 3.6, pypy3   |
 | >= v0.39         | 1.11, 2.0       | 3.5, 3.6, pypy3 |
 | >= v0.38.1       | 1.8, 1.11       | 3.5, 3.6, pypy3 |
@@ -765,10 +765,10 @@ Using the old place {{{django_tools.unittest_utils.selenium_utils}}} still works
 
 * *dev* - [[https://github.com/jedie/django-tools/compare/v0.49.0..master|compare v0.49.0...master]]
 ** TBC
-* v0.49.0.rc1 - 21.11.2021 - [[https://github.com/jedie/django-tools/compare/v0.48.3...v0.49.0.rc1|compare v0.48.3...v0.49.0.rc1]]
+* v0.49.0.rc2 - 21.11.2021 - [[https://github.com/jedie/django-tools/compare/v0.48.3...v0.49.0.rc2|compare v0.48.3...v0.49.0.rc2]]
 ** NEW: {{{VersionProtectBaseModel}}} - Protect a model against overwriting a newer entry with an older one, by adding a auto increment version number.
 ** NEW: {{{AlwaysLoggedInAsSuperUserMiddleware}}} useful for local dev server run to auto login into Django Admin
-** Enhance Selenium test helpers
+** Enhance Selenium test helpers and [[https://github.com/jedie/django-tools/issues/21|fix #21: Set chrome accept_languages in headless mode]]
 ** Update project: Tests, code-style etc.
 * v0.48.3 - 20.12.2020 - [[https://github.com/jedie/django-tools/compare/v0.47.2...v0.48.3|compare v0.47.2...v0.48.3]]
 ** NEW: {{{ImageDummy().in_memory_image_file()}}} useful for e.g.: POST a image upload via Django's test client

django_tools/__init__.py

@@ -1 +1 @@
-__version__ = '0.49.0.rc1'
+__version__ = '0.49.0.rc2'

django_tools/selenium/base.py

@@ -78,11 +78,10 @@ def __repr__(self):
         return self.items().__str__()
 
 
-def assert_browser_language(driver: RemoteWebDriver, languages: [list, tuple]):
+def assert_browser_language(driver: RemoteWebDriver, language: str):
     browser_languages = driver.execute_script('return window.navigator.languages')
-    browser_language = browser_languages[0]
-    assert browser_language in languages, (
-        f'Browser language "{browser_language}" is not in {languages}'
+    assert browser_languages == [language], (
+        f'Browser language "{browser_languages}" is not in {[language]}'
     )
 
 
@@ -235,5 +234,5 @@ def assert_local_storage_key_value(self, *, key, value):
         is_value = self.local_storage[key]
         self.assertEqual(value, is_value)
 
-    def assert_browser_language(self, languages: [list, tuple]):
-        assert_browser_language(driver=self.driver, languages=languages)
+    def assert_browser_language(self, language: str):
+        assert_browser_language(driver=self.driver, language=language)

django_tools/selenium/chromedriver.py

@@ -11,7 +11,7 @@
 from selenium import webdriver
 from selenium.webdriver.chrome.service import Service
 
-from django_tools.selenium.base import LocalStorage, SeleniumBaseTestCase, assert_browser_language
+from django_tools.selenium.base import LocalStorage, SeleniumBaseTestCase
 
 
 log = logging.getLogger(__name__)
@@ -49,7 +49,6 @@ def test_admin_login_page(self):
         '--incognito',
         '--disable-gpu',
         '--disable-dev-shm-usage',  # https://bugs.chromium.org/p/chromedriver/issues/detail?id=2473
-        '--lang=en-US'
     )
     desired_capabilities = {
         'loggingPrefs': {
@@ -58,7 +57,7 @@ def test_admin_login_page(self):
             'performance': 'ALL',
         }
     }
-    accept_languages = 'en-US,en;q=0.8'
+    accept_languages = 'en-US'
 
     @classmethod
     def setUpClass(cls):
@@ -71,8 +70,11 @@ def setUpClass(cls):
         else:
             options = webdriver.ChromeOptions()
             options.add_experimental_option('w3c', False)  # needed to get browser logs
+
+            # Note: accept_languages will be ignored in headless mode!
+            # See: https://github.com/jedie/django-tools/issues/21
+            # Work-a-round: set via "env" in Service() below
             options.add_experimental_option('prefs', {'intl.accept_languages': cls.accept_languages})
-            options.add_argument(f'--accept-language="{cls.accept_languages}"')
 
             for argument in cls.options:
                 options.add_argument(argument)
@@ -83,17 +85,20 @@ def setUpClass(cls):
             log.debug('Browser options:\n%s', pprint.pformat(options.to_capabilities()))
             service = Service(
                 executable_path=str(executable),
-                log_path=f'{cls.filename}.log'
+                log_path=f'{cls.filename}.log',
+
+                # accept_languages doesn't work in headless mode
+                # Set browser language via environment:
+                env={  # noqa -> https://github.com/SeleniumHQ/selenium/pull/10072
+                    'LANG': 'en_US',
+                    'LANGUAGE': 'en_US',
+                }
             )
             cls.driver = webdriver.Chrome(
                 options=options,
                 service=service,
             )
 
-            # Test may fail, if a other language is activated.
-            # So check this after startup:
-            assert_browser_language(driver=cls.driver, languages=('en', 'en-US'))
-
             cls.local_storage = LocalStorage(cls.driver)
 
     def get_browser_log(self):

django_tools_test_project/tests/test_unittest_selenium.py

@@ -13,6 +13,7 @@
 from selenium.common.exceptions import NoSuchElementException
 
 # https://github.com/jedie/django-tools
+from django_tools.selenium.base import assert_browser_language
 from django_tools.selenium.chromedriver import SeleniumChromiumTestCase, chromium_available
 from django_tools.selenium.django import (
     SeleniumChromiumStaticLiveServerTestCase,
@@ -29,13 +30,15 @@ class ExampleChromiumTests(SeleniumChromiumStaticLiveServerTestCase):
     def test_admin_login_page(self):
         self.driver.get(self.live_server_url + "/admin/login/")
 
-        # FIXME: Depends on version?!?
-        languages = self.driver.execute_script('return window.navigator.languages')
-        language = languages[0]
-        assert language in ('en', 'en-US')
+        # We can't check the page content, if the browser send wrong accept languages to server.
+        # Check this:
+        assert_browser_language(driver=self.driver, language='en-US')
 
+        # Following tests will fail if server response with other translations:
         self.assert_equal_page_title("Log in | Django site admin")
+        self.assert_in_page_source(f' lang="en"')
         self.assert_in_page_source('<form action="/admin/login/" method="post" id="login-form">')
+
         self.assert_no_javascript_alert()
 
 
@@ -44,8 +47,15 @@ class ExampleFirefoxTests(SeleniumFirefoxStaticLiveServerTestCase):
     def test_admin_login_page(self):
         self.driver.get(self.live_server_url + "/admin/login/")
 
+        # We can't check the page content, if the browser send wrong accept languages to server.
+        # Check this:
+        assert_browser_language(driver=self.driver, language='en-US')
+
+        # Following tests will fail if server response with other translations:
         self.assert_equal_page_title("Log in | Django site admin")
+        self.assert_in_page_source(f' lang="en"')
         self.assert_in_page_source('<form action="/admin/login/" method="post" id="login-form">')
+
         self.assert_no_javascript_alert()
 
 

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "django-tools"
-version = "0.49.0.rc1"
+version = "0.49.0.rc2"
 description = "miscellaneous tools for Django based projects"
 license = "GPL-3.0-or-later"
 authors = ["Jens Diemer <django-tools@jensdiemer.de>"]