chromium/third_party/blink/web_tests/external/wpt/css/css-grid/grid-definition/grid-limits-001.html

<!DOCTYPE html>
<link rel="help" href="https://drafts.csswg.org/css-grid/#overlarge-grids">
<link rel="author" title="Tab Atkins-Bittner" href="https://xanthir.com/contact">
<link rel="author" title="Elika J Etemad" href="http://inkedblade.net/contact">
<meta name="flags" content="should">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="../../support/computed-testcommon.js"></script>
<div id=target>
    <div id=child1></div>
    <div id=child2></div>
</div>
<style>
    #target {
        display: grid;
        position: absolute;
    }
</style>
<script>
const target = document.querySelector("#target");
const child1 = document.querySelector("#child1");
const child2 = document.querySelector("#child2");

test(()=>{
    target.style.gridTemplateRows = "repeat(9999, 1px)";
    target.style.gridTemplateColumns = "repeat(9999, 1px)";

    const height = getComputedStyle(target).height;
    const width = getComputedStyle(target).width;

    assert_equals(height, "9999px", "repeat(9999, 1px) should make grid height 9999px");
    assert_equals(width, "9999px", "repeat(9999, 1px) should make grid width 9999px");

    target.removeAttribute('style');
}, "repeat(9999) should be supported in both axises");

test(()=>{
    // Start from no explicit grid, so only implicit tracks happen
    target.style.gridAutoRows = "1px";
    target.style.gridAutoColumns = "1px";

    child1.style.gridRowEnd = "10000";
    child1.style.gridColumnEnd = "10000";

    child2.style.gridRowStart = "-10000";
    child2.style.gridColumnStart = "-10000";

    const height = getComputedStyle(target).height;
    const width = getComputedStyle(target).width;

    assert_equals(height, "19998px", "Positioning children at lines -10k and 10k should generate 19998 implicit 1px tracks.");
    assert_equals(width, "19998px", "Positioning children at lines -10k and 10k should generate 19998 implicit 1px tracks.");

    target.removeAttribute('style');
    child1.removeAttribute('style');
    child2.removeAttribute('style');
}, "Implicit grid should support lines [-10k, 10k].");
</script>