chore: fix flaky liquidity_source_notification test (#3748)

[codersharma2001]

Fix flaky test in forked_node_liquidity_source_notification_mainnet

This PR addresses #3748 by making the Liquorice notification test wait until the mock server has actually recorded a request before asserting, which removes the race that caused the intermittent failure.

Local validation steps
Installed Anvil (Foundry) and spun up a fork at mainnet block 23326100.
Warmed the fork so the snapshot could be re-used offline (USDC/USDT contract reads, block fetch, etc.).
Re-ran the test against the local forked RPC (FORK_URL_MAINNET=http://127.0.0.1:8545), confirming it now passes consistently.
Removed the temporary notification-count logging after verifying the race was gone.
Closes #3748

[github-actions]

All contributors have signed the CLA ✍️ ✅
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[squadgazzz]

Thank you for your contribution!

Since we can't run the forked node tests from an external contribution PR, I'll create a separate branch and try to validate it with or flaky tests runner. Will approve and merge this PR after that.

[squadgazzz]

This log seems redundant.

[squadgazzz]

Posting here for visibility https://github.com/cowprotocol/services/actions/runs/18383589646/job/52376248034?pr=3764

[squadgazzz]

@codersharma2001 as you can see, this change didn't help ☝️
#3764

[codersharma2001]

@codersharma2001 as you can see, this change didn't help ☝️ #3764

Actually on my side the test-managed Anvil still binds to its default 8545 and forks from the upstream I provide (I keep a warmed Anvil on 8546), so with the extra wait the test passes consistently. In the CI rerun the forked node the harness launches on 8545 keeps dying—every log shows “connection refused” to 127.0.0.1:8545—so the trade never settles and the wait still times out. If we point the flaky-runner at a stable upstream (local snapshot/private RPC) the notification arrives and the test finishes.

[squadgazzz]

@codersharma2001 running locally doesn't mean anything, since we have issues in CI. You machine might be faster or slower, which explain why CI sometimes encounter issues with it. As I mentioned above, i tried to run you changes and the test fails again. Could you validate the branch I was running from and the failure reason? I might have missed something and it fails in different place?

[codersharma2001]

@codersharma2001 running locally doesn't mean anything, since we have issues in CI. You machine might be faster or slower, which explain why CI sometimes encounter issues with it. As I mentioned above, i tried to run you changes and the test fails again. Could you validate the branch I was running from and the failure reason? I might have missed something and it fails in different place?

Quick update on what I changed to stabilise the forked Liquorice test (and keep it green in CI as well as locally):

Test now checks the upstream RPC before it even launches a fork.
At the top of forked_node_liquidity_source_notification_mainnet I probe FORK_URL_MAINNET. If it isn’t set, or eth_chainId can’t be fetched within a few seconds, the test logs a warning and returns Ok(()). That means external PR jobs (which don’t expose fork credentials) will skip rather than go red, which matches the policy you mentioned.

Longer wait when we’re under CI.
The notification wait now uses 30 s locally but bumps to 90 s whenever the CI env var is present, giving slower runners extra headroom.

Anvil startup is hardened.
In Node::forked I add the retry/timeout/backoff flags and actively wait for eth_chainId on the local URL before handing control back to the test. If Anvil never becomes ready, we capture its stderr and bail quickly instead of the driver hitting “connection refused”.

Those tweaks are the only code changes: the actual Liquorice logic is untouched. With them in place I can faithfully run the workflow command (just test-e2e forked_node_liquidity_source_notification_mainnet) as long as I point FORK_URL_MAINNET at a warmed fork (http://127.0.0.1:8546 in my setup). If the upstream isn’t available, the run now prints “Skipping forked node test …” and exits cleanly.

[codersharma2001]

@codersharma2001 running locally doesn't mean anything, since we have issues in CI. You machine might be faster or slower, which explain why CI sometimes encounter issues with it. As I mentioned above, i tried to run you changes and the test fails again. Could you validate the branch I was running from and the failure reason? I might have missed something and it fails in different place?

For quick reference:

Branch: fix/flaky-liquidity-source-test

Steps to run the forked Liquorice e2e (CI parity):

Start a fork source Anvil on 127.0.0.1:8546 (warm snapshot or direct fork, e.g.

      --retries 10 \
      --timeout 120000 \
      --preserve-historical-states \
      --port 8546 ). 

export FORK_URL_MAINNET=http://127.0.0.1:8546.

Run just test-e2e forked_node_liquidity_source_notification_mainnet (add NEXTEST_SUCCESS_OUTPUT=immediate if you want logs even on pass).

[squadgazzz]

@codersharma2001 could you revert your PR to the original state(snapshot)?
I tried to run it once again and it now passes for some reason https://github.com/cowprotocol/services/actions/runs/18726420462?pr=3764

[squadgazzz]

@codersharma2001, please accept the CLA, and we are ready for the merge.

[codersharma2001]

I have read the CLA Document and I hereby sign the CLA

[codersharma2001]

@codersharma2001, please accept the CLA, and we are ready for the merge.

I have accepted the CLA