simulators/ethereum/engine/cancun: Maintain devp2p client peering

[spencer-tb]

Description

• Fixes the engine-cancun devp2p test: Request Blob Pooled Transactions for geth.
• After the following PR: core/txpool, eth, miner: retrieve plain and blob txs separately go-ethereum#29026, to obtain a NewPooledTransactionHashes devp2p msg for blob txs, we must now peer first before sending blob txs.
• Adds an additional test where we send multiple blob txs instead of a single blob tx.

[marioevz]

Some comments, thanks!

[marioevz]

Could we take this opportunity to rename this to something more generic, like TestContext.

And also create a func NewTestContext() *TestContext { that performs all init operations required such as the t.DevP2PConnections = make(map[uint64]*devp2p.Conn) that we do in line 782.

[marioevz]

We could also create a func (t *TestContext) Close() error { that we could defer t.Close() after we call NewTestContext() when creating the context to do some proper cleanup such as the closing of the connections that are still open in t.DevP2PConnections.

[spencer-tb]

Very happy to extend to this!

My only rebutle is that we'd be adding the extra initialization steps for all the CancunBaseSpec tests, where its only required for 2 of them.

Maybe we have a generic TestContext and additionally a specific DevP2PTestContext, the latter having the init steps you mentioned. Where we only init these steps for the DevP2P tests?

(edited) What I wrote above didn't make sense, will implement your suggestions.

[spencer-tb]

I added your suggestions in: 25ffdf9

Let me know what you think :)