Makes the test more realistic by issuing an HTTP request.
Reduces coupling between test and the code under test.
The `http_server` helper was factored out into a new tests.utils module.
Trailing whitespace do not have impact on the result, they are just
unused bytes. Most text editors are configured to strip trailing
whitespaces. Remove them all in one go.
Update a handful of files to use the UNIX line ending.
François Freitag