add tests for corner cases

[remusao]

There are a few resources we might be able to leverage to test more corner cases for the parsing logic.

• https://github.com/cweb/url-testing/blob/master/urls.json
• https://webkit.org/blog/7086/url-parsing-in-webkit/
• https://www.lookout.net/test/url/
• https://www.lookout.net/test/url/url-runner.html