Digging into the test code base I've found out that some of the tests for `LoadHTML*` methods are not reliable and efficient. They use timeouts to be sure that goroutine with the server has started. And even more, in old implementation, the server started only once – all the new instances silently failed due to the occupied network port.
Here is a short overview of the proposed changes:
- it's not necessary to rely on timeouts, the server starts listening synchronously and returns control when it is ready
- once the server is run, it's stopped after a test passes
- dry out http server setup
- magic with empty closure return is eliminated
- preserve router.RunTLS coverage with integration tests
