ManicMinter e2e Test

In this chapter we will write e2e tests for the ManicMinter contract. The e2e tests will be written in Rust using the ink! e2e framework. The e2e tests will be executed on a local substrate node. Just like in previous chapter we will not include complete code from the contract to keep it short and focused on the e2e tests.

Import Crates

Let's create a new module e2e_tests within the body of the mod manicminter and import the following crates:

#[cfg(all(test, feature = "e2e-tests"))]
mod e2e_tests {
    use super::*;
    use crate::manicminter::ManicMinterRef;
    use ink::primitives::AccountId;
    use ink_e2e::build_message;
    use openbrush::contracts::ownable::ownable_external::Ownable;
    use openbrush::contracts::psp22::psp22_external::PSP22;
    use oxygen::oxygen::OxygenRef;

    type E2EResult<T> = std::result::Result<T, Box<dyn std::error::Error>>;

    const AMOUNT: Balance = 100;
    const PRICE: Balance = 10;
}

You will notice that we import Openbrush traits to invoke methods from the Oxygen contract, which is implemented using Openbrush's version of PSP22.

Instantiate Contracts

We will use the ink_e2e::Client to instantiate the contracts. The ink_e2e::Client is a wrapper around the ink_env::test environment. The ink_e2e::Client provides a convenient way to instantiate contracts and invoke contract methods.

In the declarative macro add our contracts as additional contracts:

#[ink_e2e::test(additional_contracts = "manicminter/Cargo.toml oxygen/Cargo.toml")]
async fn e2e_minting_works(mut client: ink_e2e::Client<C, E>) -> E2EResult<()> {
    let initial_balance: Balance = 1_000_000;

    // Instantiate Oxygen contract
    let token_constructor = OxygenRef::new(initial_balance);
    let oxygen_account_id = client
        .instantiate("oxygen", &ink_e2e::alice(), token_constructor, 0, None)
        .await
        .expect("token instantiate failed")
        .account_id;

    // Instantiate ManicMinter contract
    let manic_minter_constructor = ManicMinterRef::new(oxygen_account_id);
    let manic_minter_account_id = client
        .instantiate(
            "manic-minter",
            &ink_e2e::alice(),
            manic_minter_constructor,
            0,
            None,
        )
        .await
        .expect("ManicMinter instantiate failed")
        .account_id;
}

Set ManicMinter as Owner of Oxygen

We will use the build_message macro to compose the transfer_ownership method of the Oxygen contract. The client.call() executes the contract call. The call_dry_run method with owner() message verifies the result of the contract call.

// Set ManicMinter contract to be the owner of Oxygen contract
let change_owner = build_message::<OxygenRef>(oxygen_account_id.clone())
    .call(|p| p.transfer_ownership(manic_minter_account_id));
client
    .call(&ink_e2e::alice(), change_owner, 0, None)
    .await
    .expect("calling `transfer_ownership` failed");

// Verify that ManicMinter is the Oxygen contract owner
let owner = build_message::<OxygenRef>(oxygen_account_id.clone()).call(|p| p.owner());
let owner_result = client
    .call_dry_run(&ink_e2e::alice(), &owner, 0, None)
    .await
    .return_value();
assert_eq!(owner_result, manic_minter_account_id);

Set Price for Oxygen Tokens

We use the build_message macro to compose the set_price method of the ManicMinter contract. The client.call() executes the contract call.

// Contract owner sets price
let price_message = build_message::<ManicMinterRef>(manic_minter_account_id.clone())
    .call(|manicminter| manicminter.set_price(PRICE));
client
    .call(&ink_e2e::alice(), price_message, 0, None)
    .await
    .expect("calling `set_price` failed");

Mint Oxygen Tokens

We are now ready to execute manic_mint method of the ManicMinter contract. We use the build_message macro to compose the manic_mint method of the ManicMinter contract. The client.call() executes the contract call. The call_dry_run method with balance_of() message verifies the result of the contract call on the Oxygen contract.

// Bob mints AMOUNT of Oxygen tokens by calling ManicMinter contract
let mint_message = build_message::<ManicMinterRef>(manic_minter_account_id.clone())
    .call(|manicminter| manicminter.manic_mint(AMOUNT));
client
    .call(&ink_e2e::bob(), mint_message, PRICE * AMOUNT, None)
    .await
    .expect("calling `pink_mint` failed");

// Verify that tokens were minted on Oxygen contract
let bob_account_id = get_bob_account_id();
let balance_message = build_message::<OxygenRef>(oxygen_account_id.clone())
    .call(|p| p.balance_of(bob_account_id));
let token_balance = client
    .call_dry_run(&ink_e2e::bob(), &balance_message, 0, None)
    .await
    .return_value();
assert_eq!(token_balance, AMOUNT);

Execute e2e Test

The e2e tests are invoking the node which is running on the local machine. Before running the test we need to setup the environment variable CONTRACT_NODE to the executable local node. The node can be Swanky-node or any other node that implements pallet-contracts.

export CONTRACTS_NODE="YOUR_CONTRACTS_NODE_PATH"

As an example it can be set to the following value:

export CONTRACTS_NODE="/home/p/Documents/astar/target/release/astar-collator"

After setting your node path, run the following command to execute the e2e tests:

cargo test --features e2e-tests

Debugging e2e Test

If you want to print some variables and messages during the e2e test execution you can use the println! macro. The output will be printed in the terminal where the test is executed. To be able to see the printed output you need to run the test with --nocapture flag:

cargo test --features e2e-tests -- --nocapture

Summary of the e2e Test Chapter:

• We imported the required crates for e2e tests.
• We instantiated the ManicMinter and Oxygen contracts.
• We set the ManicMinter contract to be the owner of the Oxygen contract.
• We set the price for Oxygen tokens.
• We minted Oxygen tokens using the ManicMinter contract.

The full code for this example is available here.