feat: add in simulate function for ATC and EmptyTransactionSigner

[michaeltchuang]

Summary

• Ported simulate function to AtomicTransactionComposer.java (mirror Go/JS versions)
• Also created EmptyTransactionSigner class

Testing Plan

• Added some integration tests to pass simulate.feature cucumber tests

[jasonpaulos]

Thanks for this contribution. I've left comments about improvements I'd like to see, and guidance for how to add support for our existing simulation integration tests.

[jasonpaulos]

While this example may have been useful for your testing, I'm not sure how benefitial it is to check it into the repo.

In any case, we already have a set of test cases designed around SDK simulation abilities. They belong in our cucumber testing repo and their definitions are here: https://github.com/algorand/algorand-sdk-testing/blob/master/features/integration/simulate.feature. In order to approve this PR, I'd like to see these tests passing here.

You can enable them by adding @simulate to src/test/integration.tags. Then locally you can do the following to run the tests:

# Start the cucumber testing harness using docker composer
make harness

# Run the cucumber integration tests.
# Note, for more rapid iteration, you can temporarily make "@simulate" the only tag in src/test/integration.tags
# That may be beneficial anyway, since some of the other integration tests have problems running multiple times on the same network
make integration

# When done, this shuts down the testing harness
make harness-down

The first time you run make integration the testing tool will complain about missing cucumber step definitions and provide you an outline of what it thinks the definitions should be. You will need to add new functions to implement these step definitions. Existing step definitions can be found in src/test/java/com/algorand/algosdk/integration/AtomicTxnComposer.java and similar files, and for referene the Go SDK steps, which already have support for @simulate, are here: https://github.com/algorand/go-algorand-sdk/blob/dde38d8d139e1587b401a3301f1c2fe74dd55c8b/test/applications_integration_test.go

[michaeltchuang]

@jasonpaulos - Sorry on taking awhile to update this PR, it took me some time to configure my local environment for cucumber tests and getting the necessary free time to work on this. I had a question though (after I understood your feedback)...does the Go Algorand SDK include all the @simulate steps in simulate.feature? I was using it as a reference and noticed some missing

I removed the reti example test I wrote from this PR since simulate.feature test coverage would probably be sufficient

Please also let me know if I'm not on the right path on with the simulate.feature tests (i committed the first batch of integration tests into this PR now for review)