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Running agents and tests against different networks

Sometimes agents and tests need to be run on specific networks. In the case of Ethereum, you might want to use developer environments like Hardhat or Ganache as your testbed, but at some point you will also require running on top of a public testnet like Ropsten or, ultimately, the main chain.

To switch chains, you will first need to edit your chain configuration, as well as verify that the relevant addresses that come into play are funded. After that, the valory/ledger connection's configuration must be modified, and the process is slightly different for agents than for tests. Last but not least, it is important to keep in mind what the average block times are in the deploying network.

Ledger configuration for Agents

Look at you agent's aea-config.yaml last section. It should look like this:

public_id: valory/ledger:0.1.0
type: connection
      address: ${LEDGER_ADDRESS:str:http://hardhat:8545}
      chain_id: ${LEDGER_CHAIN_ID:int:31337}
There, edit the address and chain_id fields to match your requirements. In this case, we've set a local Hardhat node as our target chain, with its default id.

Ledger configuration for contract integration tests

Tests that make calls to a chain usually inherit from BaseContractTest, located at /tests/test_contracts/ That class defines the _setup_class method that overrides the valory/ledger connection's configuration:

new_config = {
    "address": url,
    "chain_id": DEFAULT_CHAIN_ID,
    "default_gas_price_strategy": "eip1559",
    "gas_price_strategies": {
        "gas_station": DEFAULT_GAS_STATION_STRATEGY,
        "eip1559": DEFAULT_EIP1559_STRATEGY,

cls.ledger_api = ledger_apis_registry.make(

As before, edit here the address and chain_id fields. That should suffice for your test to use the desired network.

Configuration for end to end tests

End to end agent tests inherit from the BaseTestEnd2End in tests/ That class defines an extra_configs attribute that is used to set the agent's configuration overrides. If your tests override that attribute, parameters defined there will be used by the agent. This does not only apply to valory/ledger connection, but to any agent configuration:

from tests.test_agents.base import BaseTestEnd2End

class MySuperHelpfulEndToEndTestBase(BaseTestEnd2End):
    """Base class for my super helpful e2e tests."""

    extra_configs = [
            "dotted_path": "vendor.valory.skills.my_super_skill_abci.models.params.args.ipfs_domain_name",
            "value": "/dns/localhost/tcp/5001/http",

All tests that inherit from this test base class will use the new configuration.

Configuration for validation timeout

This is going to play a significant role when performing transactions, since the validation logic is based on that. More specifically, the corresponding validate_timeout specified in the skill.yaml files of your skills should not be less than the average block time of the network, because timeouts and unnecessary repricing will happen too often. For example, at the time this document is written, the average block time in the Ethereum mainnet is 13.3 seconds. Therefore, we should never specify a value less than that, and it would also be reasonable to allow for more time before giving up, because it is not rare for block times to be higher and since there is no guarantee that a transaction will make it into the next block. The underlying mechanism will take care to backoff linearly, with retry_timeout as a base, while checking if the transaction has been validated, and stop when the validate_timeout is reached. An example configuration for Ethereum mainnet is provided below:

      retry_attempts: 13
      retry_timeout: 13.3
      validate_timeout: 1205

This creates the following condition:

min(retry_timeout * ((n_retries / 2) * (n_retries + 1)), validate_timeout) = min(13.3 * n_retries, 1205)

where n_retries ∈ [1, retry_attempts] is the number of times we have tried so far.

So for example if we are in the fourth retry:

min(13.3 * ((4 / 2) * (4 + 1)), 1205) = min(133, 1205) = 133

but in the last retry:

min(13.3 * ((13 / 2) * (13 + 1)), 1205) = min(1210.3, 1205) = 1205

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