use rstest to refactor unit tests

[ftupas]

Describe the feature

In #12379, the rstest framework is used to refactor unit tests.

It would be beneficial to apply this across the codebase for DRY and maintainable code without needing to create helper test utility functions like this.

reth/crates/chainspec/src/spec.rs

Lines 931 to 942 in 7209622

	/// Verifies [`ChainSpec`] configuration against expected data in given cases.
	#[cfg(any(test, feature = "test-utils"))]
	pub fn test_fork_ids(spec: &ChainSpec, cases: &[(Head, ForkId)]) {
	for (block, expected_id) in cases {
	let computed_id = spec.fork_id(block);
	assert_eq!(
	expected_id, &computed_id,
	"Expected fork ID {:?}, computed fork ID {:?} at block {}",
	expected_id, computed_id, block.number
	);
	}
	}

Moreover, fixtures can be useful to remove boiler plate code

reth/crates/net/downloaders/src/headers/reverse_headers.rs

Lines 1282 to 1285 in d47904f

	fn test_sync_target_update() {
	let client = Arc::new(TestHeadersClient::default());
	let genesis = SealedHeader::default();

reth/crates/net/downloaders/src/headers/reverse_headers.rs

Lines 1310 to 1313 in d47904f

	fn test_head_update() {
	let client = Arc::new(TestHeadersClient::default());
	let header = SealedHeader::default();

Additional context

No response

[ftupas]

@emhane issue created as per #12379 (review)_

[github-actions]

This issue is stale because it has been open for 21 days with no activity.

[github-actions]

This issue was closed because it has been inactive for 7 days since being marked as stale.