[py][bidi]: add emulation command - set_locale_override

[navin772]

User description

🔗 Related Issues

💥 What does this PR do?

Adds support for set_locale_override commands from the Emulation module - https://w3c.github.io/webdriver-bidi/#command-emulation-setLocaleOverride

🔧 Implementation Notes

Usage:

1. User context

   driver.emulation.set_locale_override(locale="en-US", user_contexts=[user_context])

2. Browsing contexts

   driver.emulation.set_locale_override(locale="zh-Hans-CN", contexts=[context_id])

💡 Additional Considerations

Initially, I thought of adding validation of locale but it added a new dep - langcodes which is not good. Since validation is done on the remote end, it is not required and any error coming from validation from remote end will be propagated by selenium as WebdriverException to the user's terminal.

🔄 Types of changes

• New feature (non-breaking change which adds functionality and tests!)

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PR Type

Enhancement

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Description

• Add set_locale_override command to emulation module

• Support both browsing contexts and user contexts

• Include comprehensive parametrized tests for various locales

• Validate mutually exclusive context parameters

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Diagram Walkthrough

flowchart LR
  A["Emulation Module"] -->|"add method"| B["set_locale_override"]
  B -->|"accepts"| C["locale parameter"]
  B -->|"accepts"| D["contexts or user_contexts"]
  D -->|"validates"| E["mutual exclusivity"]
  B -->|"executes"| F["emulation.setLocaleOverride command"]
  G["Test Suite"] -->|"parametrized tests"| H["Multiple locale formats"]
  G -->|"tests"| I["Browsing contexts"]
  G -->|"tests"| J["User contexts"]

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File Walkthrough

	Relevant files
Enhancement	emulation.py Implement set_locale_override emulation command                    py/selenium/webdriver/common/bidi/emulation.py Add new set_locale_override method to the Emulation class Accept optional locale parameter (BCP 47 format or None to clear) Support both contexts and user_contexts parameters Validate that only one of contexts or user_contexts is provided Execute the emulation.setLocaleOverride command via BiDi +34/-0
Tests	bidi_emulation_tests.py Add comprehensive tests for locale override functionality py/test/selenium/webdriver/common/bidi_emulation_tests.py Add helper function get_browser_locale to retrieve current browser locale Add parametrized test for locale override with browsing contexts (5 locale variants) Add parametrized test for locale override with user contexts (4 locale variants) Test locale normalization and various BCP 47 format combinations +68/-0

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[qodo-merge-pro]

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Below is a summary of compliance checks for this PR:

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🟢	No security concerns identified No security vulnerabilities detected by AI analysis. Human verification advised for critical code.
Ticket Compliance
🟡	🎫 #5678 🔴 Investigate and resolve repeated "Error: ConnectFailure (Connection refused)" when instantiating multiple ChromeDriver instances on Ubuntu 16.04.4 with Chrome 65/Chromedriver 2.35 using Selenium 3.9.0. Provide guidance or a fix so subsequent ChromeDriver instantiations do not log connection failure errors. Ensure any solution is validated against the specified environment and versions or document limitations.
🟡	🎫 #1234 🔴 Ensure WebDriver click() triggers JavaScript in link href for Firefox (reported regression from 2.47.1 to 2.48.x on Firefox 42). Provide a fix or regression test guaranteeing JS href execution on click in affected versions.
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[qodo-merge-pro]

PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Impact
Possible issue	Allow global locale override by default Remove the check that raises a ValueError when both contexts and user_contexts are None to align with the BiDi specification for a global locale override. py/selenium/webdriver/common/bidi/emulation.py [276-277] -if contexts is None and user_contexts is None: - raise ValueError("Must specify either contexts or userContexts") +# This block should be removed. Apply / Chat Suggestion importance[1-10]: 8 __ Why: The suggestion correctly identifies that the implementation deviates from the BiDi specification, which states that omitting both contexts and userContexts should apply a global override, not raise an error.	Medium
Learned best practice	✅ Add robust test cleanup Suggestion Impact: The test was refactored to wrap creation and use of the tab and user context in nested try/finally blocks, ensuring driver.browsing_context.close and driver.browser.remove_user_context are always executed. code diff: + try: + context_id = driver.browsing_context.create(type=WindowTypes.TAB, user_context=user_context) + try: + driver.switch_to.window(context_id) + + driver.emulation.set_locale_override(locale=value, user_contexts=[user_context]) + + driver.browsing_context.navigate(context_id, pages.url("formPage.html"), wait="complete") + + current_locale = get_browser_locale(driver) + assert current_locale == value, f"Expected locale {value}, got {current_locale}" + finally: + driver.browsing_context.close(context_id) + finally: + driver.browser.remove_user_context(user_context) Ensure the tab and user context are cleaned up even if assertions fail by wrapping them in try/finally blocks. py/test/selenium/webdriver/common/bidi_emulation_tests.py [347-363] def test_set_locale_override_with_user_contexts(driver, pages, value): """Test setting locale override with user contexts.""" user_context = driver.browser.create_user_context() + try: + context_id = driver.browsing_context.create(type=WindowTypes.TAB, user_context=user_context) + try: + driver.switch_to.window(context_id) + driver.emulation.set_locale_override(locale=value, user_contexts=[user_context]) + driver.browsing_context.navigate(context_id, pages.url("formPage.html"), wait="complete") + current_locale = get_browser_locale(driver) + assert current_locale == value, f"Expected locale {value}, got {current_locale}" + finally: + driver.browsing_context.close(context_id) + finally: + driver.browser.remove_user_context(user_context) - context_id = driver.browsing_context.create(type=WindowTypes.TAB, user_context=user_context) - - driver.switch_to.window(context_id) - - driver.emulation.set_locale_override(locale=value, user_contexts=[user_context]) - - driver.browsing_context.navigate(context_id, pages.url("formPage.html"), wait="complete") - - current_locale = get_browser_locale(driver) - assert current_locale == value, f"Expected locale {value}, got {current_locale}" - - driver.browsing_context.close(context_id) - driver.browser.remove_user_context(user_context) - [Suggestion processed] Suggestion importance[1-10]: 6 __ Why: Relevant best practice - Enforce deterministic cleanup of created resources in tests to avoid leaks and cross-test interference.	Low
Update

[cgoldberg]

LGTM.
The 2nd AI suggestion (test cleanup) might be worth doing.

Nice use of parametrize in the tests!

[navin772]

Leaving a note here for future reference:

The BiDi emulation command set_locale_override should also override the location retrieved from navigator.language/s, but as of now it's not doing that.
There is a bug for it - https://bugzilla.mozilla.org/show_bug.cgi?id=1994396 and a corresponding PR.

So, when its merged and released, one should be able to override navigator.language too.
Currently, in the tests we are using the Intl API - Intl.DateTimeFormat().resolvedOptions().locale to retrieve locale, which works fine.

Related work and PR:

1. Add hook to emulate navigator.language/s w3c/webdriver-bidi#1017
2. Add checks for "navigator.language/s" to tests for "emulation.setLocaleOverride" command. web-platform-tests/wpt#55453