Tor Browser overrides the Accept-Languages header in the page-layout tests

[cfm]

Description

Tor Browser's anti-fingerprinting protections prevent both profile-based and options-based configuration from overriding the Accept-Language header used to test localization in the Source Interface's page-layout tests.

Steps to Reproduce

1. Run LOCALES="de_DE" make translation-test.
2. Examine the contents of securedrop/tests/functional/pageslayout/screenshots.

Expected Behavior

All screenshots are in German.

Actual Behavior

Journalist Interface screenshots are in German. Source Interface screenshots are in English.

Comments

I tried using Selenium Wire to override the Accept-Language header on the wire, but it conflicts with tbselenium.¹²

tor-browser-accept-languages.txt

Footnotes

1. https://gist.github.com/woswos/38b921f0b82de009c12c6494db3f50c5?permalink_comment_id=4455252#gistcomment-4455252 ↩

2. https://github.com/webfp/tor-browser-selenium/discussions/175 ↩

[legoktm]

Is this something we should file upstream with https://github.com/webfp/tor-browser-selenium ?

[cfm]

Good idea, but I should come up with a minimal reproduction based on:

--- a/securedrop/tests/functional/web_drivers.py
+++ b/securedrop/tests/functional/web_drivers.py
@@ -50,12 +50,13 @@ def _create_torbrowser_driver(
     # we use session cookies in SD anyway (in private browsing mode all
     # cookies are set as session cookies), this should not affect session
     # lifetime.
-    pref_dict = {
-        "network.proxy.no_proxies_on": "127.0.0.1",
-        "browser.privatebrowsing.autostart": False,
-    }
+    torbrowser_options = webdriver.FirefoxOptions()
+    torbrowser_options.set_preference("network.proxy.no_proxies_on", "127.0.0.1")
+    torbrowser_options.set_preference("browser.privatebrowsing.autostart", False)
+    torbrowser_options.set_preference("privacy.resistFingerprinting", False)
     if accept_languages is not None:
-        pref_dict["intl.accept_languages"] = accept_languages
+        torbrowser_options.set_preference("privacy.spoof_english", False)
+        torbrowser_options.set_preference("intl.accept_languages", accept_languages)
 
     Path(_TBB_PATH).mkdir(parents=True, exist_ok=True)
     torbrowser_driver = None
@@ -63,8 +64,8 @@ def _create_torbrowser_driver(
         try:
             torbrowser_driver = TorBrowserDriver(
                 _TBB_PATH,
+                options=torbrowser_options,
                 tor_cfg=cm.USE_RUNNING_TOR,
-                pref_dict=pref_dict,
                 tbb_logfile_path=_LOGFILE_PATH,
             )
             logging.info("Created Tor Browser web driver")

[cfm]

I've filed this upstream in webfp/tor-browser-selenium#217. At this point, given the complexity of Tor Browser's handling of these preferences, the next step would to have translation tests use Firefox across the board and use Tor Browser only for true functional testing.