old_contents: 'use strict';
  
  var assert = require('assert');
  var Response = require('../');
  
  var res = new Response(200, {
    'Foo-Bar': 'baz-Bosh',
    'bar-foo': 'bish-Bosh'
  }, 'foo bar baz');
  assert(res.statusCode = 200);
  assert(res.headers['foo-bar'] === 'baz-Bosh');
  assert(res.headers['bar-foo'] === 'bish-Bosh');
  assert(res.body === 'foo bar baz');
  assert(res.getBody() === 'foo bar baz');
  
  res = new Response(404, {
    'Foo-Bar': 'baz-Bosh'
  }, 'Could not find page');
  assert(res.statusCode = 404);
  assert(res.headers['foo-bar'] === 'baz-Bosh');
  assert(res.body === 'Could not find page');
  var errored = false;
  try {
    res.getBody();
  } catch (ex) {
    assert(ex.statusCode === 404);
    assert(ex.headers['foo-bar'] === 'baz-Bosh');
    assert(res.body === 'Could not find page');
    errored = true;
  }
  if (!errored) {
    throw new Error('res.getBody() should throw an error when the status code is 404');
  }
  console.log('tests passed');
  
new_contents: 'use strict';
  
  var assert = require('assert');
  var Response = require('../');
  
  var res = new Response(200, {
    'Foo-Bar': 'baz-Bosh',
    'bar-foo': 'bish-Bosh'
  }, 'foo bar baz', 'http://example.com');
  assert(res.statusCode = 200);
  assert(res.headers['foo-bar'] === 'baz-Bosh');
  assert(res.headers['bar-foo'] === 'bish-Bosh');
  assert(res.body === 'foo bar baz');
  assert(res.url === 'http://example.com');
  assert(res.getBody() === 'foo bar baz');
  
  res = new Response(404, {
    'Foo-Bar': 'baz-Bosh'
  }, 'Could not find page', 'http://example.com');
  assert(res.statusCode = 404);
  assert(res.headers['foo-bar'] === 'baz-Bosh');
  assert(res.body === 'Could not find page');
  assert(res.url === 'http://example.com');
  var errored = false;
  try {
    res.getBody();
  } catch (ex) {
    assert(ex.statusCode === 404);
    assert(ex.headers['foo-bar'] === 'baz-Bosh');
    assert(ex.body === 'Could not find page');
    assert(ex.url === 'http://example.com');
    errored = true;
  }
  if (!errored) {
    throw new Error('res.getBody() should throw an error when the status code is 404');
  }
  console.log('tests passed');
  
subject: Update tests for `res.url` and `err.url`