text: 'use strict';
  
  // Tests below are not from WPT.
  
  require('../common');
  const assert = require('assert');
  
  {
    const params = new URLSearchParams();
    assert.throws(() => {
      params.toString.call(undefined);
    }, {
      code: 'ERR_INVALID_THIS',
      name: 'TypeError',
      message: 'Value of "this" must be of type URLSearchParams'
    });
  }
  
  // The URLSearchParams stringifier mutates the base URL using
  // different percent-encoding rules than the URL itself.
  {
    const myUrl = new URL('https://example.org?foo=~bar');
    assert.strictEqual(myUrl.search, '?foo=~bar');
    myUrl.searchParams.sort();
    assert.strictEqual(myUrl.search, '?foo=%7Ebar');
  }
  