Function polkadot_service::chain_spec::polkadot_testnet_genesis

pub fn polkadot_testnet_genesis(
    wasm_binary: &[u8],
    initial_authorities: Vec<(AccountId, AccountId, BabeId, GrandpaId, ImOnlineId, ValidatorId, AssignmentId, AuthorityDiscoveryId)>,
    _root_key: AccountId,
    endowed_accounts: Option<Vec<AccountId>>
) -> GenesisConfig

Helper function to create polkadot GenesisConfig for testing