Bug 1978027 - [wdspec] Update "test_timezone_offset" to assert timezone offset instead of timezone id. r=webdriver-reviewers,jdescottes

Differential Revision: https://phabricator.services.mozilla.com/D259031

Author: lutien

testing/web-platform/tests/webdriver/tests/bidi/emulation/set_timezone_override/conftest.py

@@ -55,3 +55,16 @@ def another_timezone(default_timezone, some_timezone):
 
     raise Exception(
         f"Unexpectedly could not find timezone different from the default {default_timezone}")
+
+
+@pytest_asyncio.fixture
+async def get_timezone_offset(bidi_session):
+    async def get_timezone_offset(timestamp, context):
+        result = await bidi_session.script.evaluate(
+            expression=f"(new Date({timestamp})).getTimezoneOffset()",
+            target=ContextTarget(context["context"]),
+            await_promise=False,
+        )
+        return result["value"]
+
+    return get_timezone_offset

testing/web-platform/tests/webdriver/tests/bidi/emulation/set_timezone_override/timezone.py

@@ -33,15 +33,15 @@ async def test_timezone_set_override_and_reset(bidi_session, top_context,
     assert await get_current_timezone(top_context) == default_timezone
 
 
-@pytest.mark.parametrize("timezone_offset", ["+10:00"])
-async def test_timezone_offset(bidi_session, top_context, get_current_timezone,
-        default_timezone, timezone_offset):
-    assert await get_current_timezone(top_context) == default_timezone
-
+@pytest.mark.parametrize("timezone_offset", ["+10", "-10"])
+async def test_timezone_offset(
+    bidi_session, new_tab, get_timezone_offset, timezone_offset
+):
     # Set timezone override.
     await bidi_session.emulation.set_timezone_override(
-        contexts=[top_context["context"]],
-        timezone=timezone_offset
+        contexts=[new_tab["context"]], timezone=f"{timezone_offset}:00"
     )
 
-    assert await get_current_timezone(top_context) == timezone_offset
+    assert await get_timezone_offset(1753453789196, new_tab) == int(
+        timezone_offset
+    ) * (-60)