Test for click, of somewhat abusive dynamic subcommand creation and argument passing.

clicktest.py

import re
import click


# This is obviously a placeholder for testing purposes, and would actually use Site.matches
sites = {}
for site in ('archiveofourown', 'fanfiction', 'spacebattles'):
    @click.command()
    @click.argument('url')
    def cmd(url, *args, **kwargs):
        print(url, kwargs)

    if site == 'spacebattles':
        cmd = click.option('--include-index/--no-include-index', default=False)(cmd)

    sites[site] = cmd


@click.group()
def cli():
    pass


@cli.command(context_settings=dict(ignore_unknown_options=True, allow_extra_args=True))
@click.pass_context
def download(ctx):
    # Could have a 'url' parameter, but this setup lets interleaved arguments
    # work, since allow_extra_args *doesn't* uninterleave unknown arguments,
    # so `download --include-index http://...` would consider `--include-
    # index` to be the URL.
    leftover = []
    handler = None
    for arg in ctx.args:
        if not handler:
            site = re.match(r'https?://(?:[^\.]+?\.)?([^\.]+?)\..+', arg)
            if site:
                handler = sites.get(site.group(1))
                # All subcommands get given a 'url' parameter, so set this up first
                leftover.insert(0, arg)
                continue
        leftover.append(arg)

    if handler:
        subctx = handler.make_context(ctx.info_name, leftover, ctx)
        handler.invoke(subctx)
    else:
        click.echo(download.get_help(ctx))


if __name__ == '__main__':
    # Run as: python clicktest.py download --include-index https://forums.spacebattles.com/threads/miracles-of-ancient-wonder-rwby-exalted.389319/page-131#post-40743772 --include-index
    cli()