How to locally test interaction with external contracts (chainlink and pyth oracles )?

Question

I have a Solana smart contract (written with Anchor) that interacts with Pyth and Chainlink Solana oracles. In EVM world, we would either redeploy the necessary contracts locally in the test start-up and configure them ourselves or perform fork-testing (forking the state of the mainnet and running tests independently locally).

Problems with forking:

• I've found this answer on how to "fork" Solana programs and accounts, but I am not sure if I can configure it so the anchor test runner starts up and loads the accounts for me.
• I am not sure how to interact with the program from JS after it's in my local network. I don't have the IDL available.

Problems with setting things up manually:

• I've found this answer on how to retrieve the on-chain programs and insert them inside the anchor test runner, but I am not sure how to interact with the program from JS after it's in my local network. I don't have the IDL available.

If anyone has had the experience of writing localnet tests for either of these oracles or any other external program, please share your experience.

Answer 1

I was able to solve the issue by making use of Anchor.toml [test.validator.clone] attribute (docs)

1. First I clone the necessary program solana program dump --url devnet HEvSKofvBgfaexv23kMabbYqxasxU3mQ4ibBMEmJWHny chainlink.so
2. Update the Anchor.toml file:

# Because I am copying many accounts in my tests, I need to wait quite a long time
[test]
startup_wait = 100000

# The cluster from which I am cloning the accounts
[test.validator]
url = "https://api.devnet.solana.com"

# The external programs I want to deploy
[[test.genesis]]
address = "<chainlink validator address>"
program = "chainlink.so"

# Addresses that I want to clone (e.g. price feed account from chainlink or pyth)
[[test.validator.clone]]
address = "<address of account I'm using in my tests>"

[[test.validator.clone]]
address = "<address of account I'm using in my tests>"