The with_wheel fixture doesn't have a value and isn't ever referenced
within a test function.

To avoid typing it every test function, change tests to use
pytest.mark.usefixture. It will no longer appear as an argument.

https://docs.pytest.org/en/latest/how-to/fixtures.html#use-fixtures-in-classes-and-modules-with-usefixtures

It was very hard for me to figure out what this test was designed
to test. It turns out that when this test was promoted from unit
to functional someone forgot to copy the docstring

9faa9aef

Use pyupgrade to convert simple string formatting to use f-string
syntax. pyupgrade is intentionally timid and will not create an f-string
if it would make the expression longer or if the substitution parameters
are anything but simple names or dotted names.

Unnecessary since dropping Python 2 support. In Python 3, all classes
are new style classes.

Downloading is done at the end of the download command
just like any other requirement. This is necessary to avoid
archiving editable requirements to a zip file when running
pip wheel.

Previously we were copying an existing wheel to a file with a
different distribution name. When using stricter metadata parsing this
would fail, so now we use a more conformant dummy wheel function.

Reduces coupling between tests and code.

Reduces coupling between tests and code.

Reduces coupling between tests and code.

This and the next several changes will uncouple the tests from the
current implementation, allowing us to factor the actual file download
out of `unpack_file_url` and `unpack_http_url`.

As mentioned in https://snarky.ca/the-challenges-in-designing-a-library-for-pep-425/
this tag doesn't make much sense + it impedes our usage of
packaging.tags.

In terms of backwards-compatibility, we attest to try to match
compatible wheels as best as possible, and this tag doesn't represent
that.

Per PEP 599:
https://www.python.org/dev/peps/pep-0599/

As spelled on https://pypi.org/.

This reflects the change in the tag name in PEP 571.

The flag makes pip prefer an older but valid binary distributions over a newer source distributions.

Fixes #3785.

This essentially allows me to do an overall check general check by running the tests using pytest's `-k basic` syntax. Given that I like running tests often and that, in general, I make typos more often than changes that break core functionality, I think this will reduce cycle times for me.