End-to-end tests for transfers from Ethereum to Namada using the fake events endpoint

[james-chf]

We should have end-to-end tests testing submission of fake Ethereum events to a Namada validator. These tests should be able to be run in CI. They should cover (at least) what the shell script test does in https://github.com/anoma/namada/pull/430 - i.e. sending wDAI to an established address on a Namada chain - but this issue is open ended, we need to come up with more test cases. Examples of things we need to cover:

• Namada chains with different numbers of validators (one, more than one) and different fractional voting powers
• transfers sent around the time of epoch transitions and validator set changes, when fractional voting powers may change

As a separate later issue - we will have equivalent end-to-end tests that use the fully deployed Ethereum smart contracts rather than the direct events submission endpoint.

To scope/plan out this issue for the moment (though perhaps this issue should become a tracking issue for individual issues for individual e2e tests)

• [ ] e2e test that sends an ERC20 transfer to an address on a Namada chain (e.g. similar to the test at https://github.com/anoma/ethereum-bridge-e2e-tests/commit/2746512b6afb32c70f768da22ea1252d6f9556ba)
  • [ ] implicit receiver address
  • [ ] established receiver address
• [ ] extend the above e2e tests to work with chains with more than one validator (depends on https://github.com/anoma/namada/issues/1055)

[cwgoes]

@james-chf Is this status up to date?

[james-chf]

I've updated the checklist in the body of this issue - the previous second task (e2e tests relating to multitoken transfers with namadac transfer) has its own issue now so have removed it (https://github.com/anoma/namada/issues/578). Scoped this issue to be about adding e2e tests that submit fake Ethereum events to a namada node to test out Ethereum -> Namada transfers.