urlpattern/resources/urlpattern-compare-tests.js

function runTests(data) {
  for (let entry of data) {
    test(function() {
      const left = new URLPattern(entry.left);
      const right = new URLPattern(entry.right);

      assert_equals(URLPattern.compareComponent(entry.component, left, right), entry.expected);

      // We have to coerce to an integer here in order to avoid asserting
      // that `+0` is `-0`.
      const reverse_expected = ~~(entry.expected * -1);
      assert_equals(URLPattern.compareComponent(entry.component, right, left), reverse_expected, "reverse order");

      assert_equals(URLPattern.compareComponent(entry.component, left, left), 0, "left equality");
      assert_equals(URLPattern.compareComponent(entry.component, right, right), 0, "right equality");
    }, `Component: ${entry.component} ` +
       `Left: ${JSON.stringify(entry.left)} ` +
       `Right: ${JSON.stringify(entry.right)}`);
  }
}

promise_test(async function() {
  const response = await fetch('resources/urlpattern-compare-test-data.json');
  const data = await response.json();
  runTests(data);
}, 'Loading data...');