[py][bidi]: add set_timezone_override command in emulation

py/selenium/webdriver/common/bidi/emulation.py

@@ -215,3 +215,38 @@ def set_geolocation_override(
             params["userContexts"] = user_contexts
 
         self.conn.execute(command_builder("emulation.setGeolocationOverride", params))
+
+    def set_timezone_override(
+        self,
+        timezone: Optional[str] = None,
+        contexts: Optional[list[str]] = None,
+        user_contexts: Optional[list[str]] = None,
+    ) -> None:
+        """Set timezone override for the given contexts or user contexts.
+
+        Parameters:
+        -----------
+            timezone: Timezone identifier (IANA timezone name or offset string like '+01:00'),
+                     or None to clear the override.
+            contexts: List of browsing context IDs to apply the override to.
+            user_contexts: List of user context IDs to apply the override to.
+
+        Raises:
+        ------
+            ValueError: If both contexts and user_contexts are provided, or if neither
+                       contexts nor user_contexts are provided.
+        """
+        if contexts is not None and user_contexts is not None:
+            raise ValueError("Cannot specify both contexts and user_contexts")
+
+        if contexts is None and user_contexts is None:
+            raise ValueError("Must specify either contexts or user_contexts")
+
+        params: dict[str, Any] = {"timezone": timezone}
+
+        if contexts is not None:
+            params["contexts"] = contexts
+        elif user_contexts is not None:
+            params["userContexts"] = user_contexts
+
+        self.conn.execute(command_builder("emulation.setTimezoneOverride", params))

py/test/selenium/webdriver/common/bidi_emulation_tests.py

@@ -21,6 +21,22 @@
 from selenium.webdriver.common.window import WindowTypes
 
 
+def get_browser_timezone_string(driver):
+    result = driver.script._evaluate(
+        "Intl.DateTimeFormat().resolvedOptions().timeZone",
+        {"context": driver.current_window_handle},
+        await_promise=False,
+    )
+    return result.result["value"]
+
+
+def get_browser_timezone_offset(driver):
+    result = driver.script._evaluate(
+        "new Date().getTimezoneOffset()", {"context": driver.current_window_handle}, await_promise=False
+    )
+    return result.result["value"]
+
+
 def get_browser_geolocation(driver, user_context=None):
     origin = driver.execute_script("return window.location.origin;")
     driver.permissions.set_permission("geolocation", PermissionState.GRANTED, origin, user_context=user_context)
@@ -214,3 +230,66 @@ def test_set_geolocation_override_with_error(driver, pages):
 
     result = get_browser_geolocation(driver)
     assert "error" in result, f"Expected geolocation error, got: {result}"
+
+
+def test_set_timezone_override_with_context(driver, pages):
+    """Test setting timezone override with a browsing context."""
+    context_id = driver.current_window_handle
+    pages.load("blank.html")
+
+    initial_timezone_string = get_browser_timezone_string(driver)
+
+    # Set timezone to Tokyo (UTC+9)
+    driver.emulation.set_timezone_override(timezone="Asia/Tokyo", contexts=[context_id])
+
+    timezone_offset = get_browser_timezone_offset(driver)
+    timezone_string = get_browser_timezone_string(driver)
+
+    # Tokyo is UTC+9, so the offset should be -540 minutes (negative because it's ahead of UTC)
+    assert timezone_offset == -540, f"Expected timezone offset -540, got: {timezone_offset}"
+    assert timezone_string == "Asia/Tokyo", f"Expected timezone 'Asia/Tokyo', got: {timezone_string}"
+
+    # Clear the timezone override
+    driver.emulation.set_timezone_override(timezone=None, contexts=[context_id])
+
+    # verify setting timezone to None clears the timezone override
+    timezone_after_clear_with_none = get_browser_timezone_string(driver)
+    assert timezone_after_clear_with_none == initial_timezone_string
+
+
+def test_set_timezone_override_with_user_context(driver, pages):
+    """Test setting timezone override with a user context."""
+    user_context = driver.browser.create_user_context()
+    context_id = driver.browsing_context.create(type=WindowTypes.TAB, user_context=user_context)
+
+    driver.switch_to.window(context_id)
+    pages.load("blank.html")
+
+    driver.emulation.set_timezone_override(timezone="America/New_York", user_contexts=[user_context])
+
+    timezone_string = get_browser_timezone_string(driver)
+    assert timezone_string == "America/New_York", f"Expected timezone 'America/New_York', got: {timezone_string}"
+
+    driver.emulation.set_timezone_override(timezone=None, user_contexts=[user_context])
+
+    driver.browsing_context.close(context_id)
+    driver.browser.remove_user_context(user_context)
+
+
+@pytest.mark.xfail_firefox(reason="Firefox returns UTC as timezone string in case of offset.")
+def test_set_timezone_override_using_offset(driver, pages):
+    """Test setting timezone override using offset."""
+    context_id = driver.current_window_handle
+    pages.load("blank.html")
+
+    # set timezone to India (UTC+05:30) using offset
+    driver.emulation.set_timezone_override(timezone="+05:30", contexts=[context_id])
+
+    timezone_offset = get_browser_timezone_offset(driver)
+    timezone_string = get_browser_timezone_string(driver)
+
+    # India is UTC+05:30, so the offset should be -330 minutes (negative because it's ahead of UTC)
+    assert timezone_offset == -330, f"Expected timezone offset -540, got: {timezone_offset}"
+    assert timezone_string == "+05:30", f"Expected timezone '+05:30', got: {timezone_string}"
+
+    driver.emulation.set_timezone_override(timezone=None, contexts=[context_id])