Test if alternative stylesheet is blocking scripts

Description

<link rel="alternate stylesheet" title="x" href="foo.css?pipe=trickle(d2)">
<script>
assert_equals(document.querySelector('link').sheet.cssRules[0].zIndex, 10);
</script>

Contributor guide

Tech stack

htmlcssjavascript

Domain

testing

Issue type

test

DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.

2

Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.

under 1 hour

Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.

stale

ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.

clear

Prerequisites

web platform tests setupHTML spec knowledge

Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.

70

Research direction

Create a test file in the wpt repository (likely under html/semantics/scripting 1/) that verifies that an alternate stylesheet does not block script execution. Use the provided HTML snippet with a trickle delay on the stylesheet and an assertion that the script runs before the stylesheet loads. Refer to the linked PR #4828 and the spec section on interactions of styling and scripting for guidance. Ensure the test follows testharness.js conventions and check for existing similar tests.