Rework fetch_bytes and _fetch_pypi_json patches to make testing easier. Various improvements to test_micropip. The main feature is a new fixture
'mock_fetch' with an add_pkg method that takes a package name, a map
from version to requirements, and a choice of platform. This should
hopefully make writing more tests a lot easier (which is good because
we could use more micropip test coverage but we are limited by the
difficulty of writing good tests).

This also adds a fixture to create distinct dummy package names and
enables @pytest.mark.asyncio to handle the async calls rather than
using `asyncio.get_event_loop.run_until_complete`.
#!/bin/sh
#
# An example hook script to check the commit log message taken by
# applypatch from an e-mail message.
#
# The hook should exit with non-zero status after issuing an
# appropriate message if it wants to stop the commit.  The hook is
# allowed to edit the commit message file.
#
# To enable this hook, rename this file to "applypatch-msg".

. git-sh-setup
commitmsg="$(git rev-parse --git-path hooks/commit-msg)"
test -x "$commitmsg" && exec "$commitmsg" ${1+"$@"}
:

#!/bin/sh
#
# An example hook script to check the commit log message taken by
# applypatch from an e-mail message.
#
# The hook should exit with non-zero status after issuing an
# appropriate message if it wants to stop the commit.  The hook is
# allowed to edit the commit message file.
#
# To enable this hook, rename this file to "applypatch-msg".

. git-sh-setup
commitmsg="$(git rev-parse --git-path hooks/commit-msg)"
test -x "$commitmsg" && exec "$commitmsg" ${1+"$@"}
:
