fix(plugins/forks): Make fork_covariant_parametrize into a marker

[marioevz]

🗒️ Description

Convert fork_covariant_parametrize into a marker pytest.mark.fork_parametrize in order to not have to import the function.

🔗 Related Issues

None

✅ Checklist

• All: Set appropriate labels for the changes.
• All: Considered squashing commits to improve commit history.
• All: Added an entry to CHANGELOG.md.
• All: Considered updating the online docs in the ./docs/ directory.
• Tests: All converted JSON/YML tests from ethereum/tests have been added to converted-ethereum-tests.txt.
• Tests: A PR with removal of converted JSON/YML tests from ethereum/tests have been opened.
• Tests: Included the type and version of evm t8n tool used to locally execute test cases: e.g., ref with commit hash or geth 1.13.1-stable-3f40e65.
• Tests: Ran mkdocs serve locally and verified the auto-generated docs for new tests in the Test Case Reference are correctly formatted.

[danceratopz]

Nice! I've warmed up this approach 🙂 Although it is possible to achieve the same functionality by adding a parametrized fixture that uses the fork fixture, I find parameterizing the test function much cleaner, explicit and easier to read.

I also prefer a pytest marker over a decorator, even if they achieve the same thing. It feels pytestic 🙂

To keep syntax more consistent with pytest.mark.parametrize(), I would suggest to:

1. Rename the marker pytest.mark.parametrize_by_fork().
2. Change the parameter_names list and fn keyword arguments to str positional arguments to be more consistent with pytest.mark.parametrize's syntax (for argnames and argvalues).

Then you have, for example,

@pytest.mark.parametrize_by_fork(
    "header_excess_blobs_delta", lambda fork: range(1, fork.max_blobs_per_block())
)
@pytest.mark.parametrize_by_fork(
    "parent_blobs", lambda fork: range(0, fork.target_blobs_per_block() + 1)
)
@pytest.mark.parametrize("parent_excess_blobs", [0])  # Start at 0
@pytest.mark.parametrize("new_blobs", [1])
def test_invalid_excess_blob_gas_target_blobs_increase_from_zero(
...

What do you think?

[marioevz]

@danceratopz great suggestions, I'll apply them in a bit!