The setup_contract_test! macro

When deploying contracts with the abigen! macro, as shown in the previous sections, the user can:

• change the default configuration parameters
• launch several providers
• create multiple wallets
• create specific assets, etc.

However, it is often the case that we want to test only the contract methods and we want to simply deploy the contract with the default configuration parameters. The setup_contract_test! macro does exactly that. When expanded, the setup_contract_test! macro will:

1. run the abigen
2. launch a local provider
3. setup one wallet
4. deploy the selected contract

The setup code that you have seen in previous sections gets reduced to:

        setup_contract_test!(
            contract_instance,
            wallet,
            "packages/fuels/tests/contracts/contract_test"
        );

        let response = contract_instance
            .methods()
            .initialize_counter(42)
            .call()
            .await?;

        assert_eq!(42, response.value);

The input of the macro are the contract instance variable name, wallet variable name and the forc project path. Both the contract instance and wallet variables get brought into context and they can be used further in the code.

Note The same contract can be deployed several times as the macro deploys the contracts with salt. You can also deploy different contracts to the same provider using a shared wallet.

If you want to deploy contracts to the same provider, you have to set the wallet name of the first macro to wallet and all the remaining wallet names to None. The first macro will create wallet and bring it into context, and the other macros will use it instead of creating new ones. Let's see it in an example.

    // The first wallet name must be `wallet`
    setup_contract_test!(
        foo_contract_instance,
        wallet,
        "packages/fuels/tests/contracts/foo_contract"
    );
    let foo_contract_id = foo_contract_instance.get_contract_id();

    // The macros that want to use the `wallet` have to set
    // the wallet name to `None`
    setup_contract_test!(
        foo_caller_contract_instance,
        None,
        "packages/fuels/tests/contracts/foo_caller_contract"
    );
    let foo_caller_contract_id = foo_caller_contract_instance.get_contract_id();

    setup_contract_test!(
        foo_caller_contract_instance2,
        None,
        "packages/fuels/tests/contracts/foo_caller_contract"
    );
    let foo_caller_contract_id2 = foo_caller_contract_instance2.get_contract_id();

    // Because we deploy with salt, we can deploy the same contract multiple times
    assert_ne!(foo_caller_contract_id, foo_caller_contract_id2);

    // The first contract can be called because they were deployed on the same provider
    let bits = *foo_contract_id.hash();
    let res = foo_caller_contract_instance
        .methods()
        .call_foo_contract(Bits256(bits), true)
        .set_contracts(&[foo_contract_id.clone()]) // Sets the external contract
        .call()
        .await?;
    assert!(res.value);

    let res = foo_caller_contract_instance2
        .methods()
        .call_foo_contract(Bits256(bits), true)
        .set_contracts(&[foo_contract_id.clone()]) // Sets the external contract
        .call()
        .await?;
    assert!(res.value);

In this example, three contracts are deployed on the same provider using the wallet. The second and third macro use the same contract but have different IDs because of the deployment with salt. Both of them can call the first contract by using its ID.

In addition, you can manually create the wallet variable and then use it inside the macro. This is useful if you want to create custom wallets or providers, but still want to use the macro to reduce boilerplate code. Below is an example of this approach.

    let config = WalletsConfig::new(Some(2), Some(1), Some(DEFAULT_COIN_AMOUNT));

    let mut wallets = launch_custom_provider_and_get_wallets(config, None, None).await;
    let wallet = wallets.pop().unwrap();
    let wallet_2 = wallets.pop().unwrap();

    setup_contract_test!(
        contract_instance,
        None,
        "packages/fuels/tests/contracts/contract_test"
    );