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.
* TST: linkcheck: make tests more flexible
* CLN: linkcheck: flake8, mypy
* REF: linkcheck: docpath->filename, write_jsonline->write_linkstat
* REF: linkcheck: remove redundant call to doc2path
* TST: linkcheck: show JSON obj structure in test
* REF: linkcheck: remove docname from JSON obj because it's redundant (use path2doc(filename) if necessary)
* TST: linkcheck: don't test row[info] output (see comments for examples)
In Python 3, the default encoding of source files is utf-8. The encoding
cookie is now unnecessary and redundant so remove it. For more details,
see the docs:
https://docs.python.org/3/howto/unicode.html#the-string-type
> The default encoding for Python source code is UTF-8, so you can
> simply include a Unicode character in a string literal ...
Includes a fix for the flake8 header checks to stop expecting an
encoding cookie.
To avoid needing to turn off anchor checking across the entire
documentation allow skipping based on matching the anchor against a
regex.
Some sites/pages use JavaScript to perform anchor assignment in a
webpage, which would require rendering the page to determine whether
the anchor exists. Allow fine grain control of whether the anchor is
checked based on pattern matching, until such stage as the retrieved
URLs can be passed through an engine for deeper checking on the HTML
doctree.
