The test runner also launches an HTTP server.

The server runs on port 9180 and serves the content from test/www
directory. Any tests can use this base URL to load test content and
to exercise certain PhantomJS API.

https://github.com/ariya/phantomjs/issues/12439
Port loading tests of web page.

https://github.com/ariya/phantomjs/issues/12439
Port custom headers testing of web page.

The HTTP server launched by the test runner has a new endpoint called
/echo. This simply echoes back some information (current on the made
request, in the future it will be expanded to further information)
formatted as JSON. This echo system facilitates easy testing for request
header manipulation feature.

https://github.com/ariya/phantomjs/issues/12439
Speed-up the tests: default auto-exit timeout is set to 1 second.

This reduces the total test duration from 72 seconds to 54 seconds.

https://github.com/ariya/phantomjs/issues/12439
Port the test for resource request error handling.

https://github.com/ariya/phantomjs/issues/12439