testfix(transaction-controller): Refactor provider setup to provide correct providers and tracker

[legobeat]

Explanation

Refactors tests so that providers are injected appropriately in the MockMultichainTransaction.

The error is interacting with a separate bug in @metamask/eth-block-tracker < v9.0.3 (@metamask/nonce-tracker < 6.0.0), which is why we don't see them failing until #4329 / #4327

References

• fix(transaction-controller): Return global ethQuery when !isMultichainEnabled #4390
• deps(transaction-controller): @metamask/nonce-tracker@^5.0.0->^6.0.0 #4327
• chore(deps): bump @metamask/nonce-tracker from 5.0.0 to 6.0.0 #4329

Changelog

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've highlighted breaking changes using the "BREAKING" category above as appropriate

[legobeat]

Note: Mismatching provider here (e.g. supplying HTTPS_PROVIDERS.mainnet) did not cause tests to fail. This suggests that some further coverage could be desired, to catch situations were blockTracker and provider inadvertently are on different chains/networks?

[legobeat]

(lint fix due to rebase on top of #4382)

[mcmire]

Ideally we shouldn't need to create specific providers for specific use cases. We shouldn't be hitting the network at all, so if we do need a provider we should be able to make a fake version using FakeProvider. But, as a fix this PR makes sense.

[mcmire]

The problem this solves is a good example of why sharing variables among tests by initializing them outside of all tests can lead to misleading and difficult to debug behavior (since a variable may have state that's changed in one test and then bleeds over into another test). This fix makes sense, but if we really need specific block trackers and providers it would be better to create them on the fly in tests, using a helper function to assist. See here for more: https://github.com/MetaMask/contributor-docs/blob/main/docs/unit-testing.md#reset-shared-variables (expand the triangle for an example)

[legobeat]

Fully agreed! The end state here is still not as I'd like it either but had to draw the line somewhere ;^^