feat: bouncer can observe past events

[j4m1ef0rd]

Pull Request

Closes: PRO-1550

Checklist

Please conduct a thorough self-review before opening the PR.

• [x] I am confident that the code works.
• [ ] I have written sufficient tests.
• [ ] I have written and tested required migrations.
• [ ] I have updated documentation where appropriate.

Summary

@acdibble or someone from product, can you please check substrate.ts. @albert-llimos can you please check I didn't screw up your GasLimitCCM test.

• Added a utility that gets the past events from x blocks ago.
• A class that caches events so its fast for later historical lookups.
  • cache can handle reorgs
  • cache tracks the latest finalised block number and tracks pending requests so it will do the minimum rpc calls as possible (ie. No duplicate lookups).
• New observeEvents function that is able to find matches from past events and return a list.
  • if no event it found it will continue to look at new events as usual.
• Changed observeEvent to use the new observeEvents function and just take the first match.
  • Also extended observeEvents to be able to look at past events. If no historicCheckBlocks is provided, then the behaviour is the same as before.
• Refactored the FoK test and the GasLimitCCM test to use the new functions.

Out of scope: Caching the historic events. Each observeEvents call will retrieve the events for each block from the api each time. Could be a problem if running the test on a real network or if we start to use this a lot in tests. Supporting reorgs on the event cache. Seems we are only using it on the StateChain for now. who cares about scopes anyways.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 71%. Comparing base (a49451d) to head (1855518). Report is 1 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #5136 +/- ## ====================================== - Coverage 71% 71% -0% ====================================== Files 458 458 Lines 82125 81981 -144 Branches 82125 81981 -144 ====================================== - Hits 58138 57939 -199 - Misses 20917 20970 +53 - Partials 3070 3072 +2 ```

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[martin-chainflip]

cool feature!

[albert-llimos]

Very happy to get rid of the gas limit test's spaghetti code to handle that edge case, good stuff!

[acdibble]

We could probably set up an indexer docker container and then you could run SQL queries against the blocks instead

[msgmaxim]

We could probably set up an indexer docker container and then you could run SQL queries against the blocks instead

I like the idea, but what will happen when the protocol makes changes to the evens (or adds new ones?). Presumably we won't be able to run bouncer tests until the indexer is updated too? I'm not 100% sure how this works, but I think currently it is maintained by the product team? Of course one solution would be to make it the protocol's team responsibility to update it 🤷. Not sure, but maybe something to consider.