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Deploy a smart contract on Bubs testnet ​

In this tutorial, we will deploy a smart contract to the Bubs testnet.

Dependencies ​

Setup ​

First, in your $HOME directory, set up a new project folder for this tutorial and init the project with npm:

bash
cd $HOME
mkdir counter-project && cd counter-project && npm init -y
cd $HOME
mkdir counter-project && cd counter-project && npm init -y

Next, initialize a Foundry project with the following command:

bash
forge init counter_contract
forge init counter_contract

Create your smart contract ​

Take a look at the Counter.sol file in your counter-project/counter_contract/src directory:

solidity
// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.13;

contract Counter {
    uint256 public number;

    function setNumber(uint256 newNumber) public {
        number = newNumber;
    }

    function increment() public {
        number++;
    }
}
// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.13;

contract Counter {
    uint256 public number;

    function setNumber(uint256 newNumber) public {
        number = newNumber;
    }

    function increment() public {
        number++;
    }
}

The contract contains a public unsigned integer variable named "number". There are two public functions in this contract. The setNumber function allows anyone to set a new value for the "number" variable, while the increment function increases the value of "number" by one each time it's called.

You can learn more about Solidity and smart contract programming.

To compile the contract, run the following forge command from the $HOME/counter-project/counter_contract/ directory:

bash
forge build
forge build

Your output should look similar to the following:

bash
[⠢] Compiling...
[⠔] Compiling 21 files with 0.8.19
[⠑] Solc 0.8.19 finished in 1.24s
Compiler run successful
[⠢] Compiling...
[⠔] Compiling 21 files with 0.8.19
[⠑] Solc 0.8.19 finished in 1.24s
Compiler run successful

Test your smart contract ​

Now, open the test/Counter.t.sol file:

solidity
// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.13;

import "forge-std/Test.sol";
import "../src/Counter.sol";

contract CounterTest is Test {
    Counter public counter;

    function setUp() public {
        counter = new Counter();
        counter.setNumber(0);
    }

    function testIncrement() public {
        counter.increment();
        assertEq(counter.number(), 1);
    }

    function testSetNumber(uint256 x) public {
        counter.setNumber(x);
        assertEq(counter.number(), x);
    }
}
// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.13;

import "forge-std/Test.sol";
import "../src/Counter.sol";

contract CounterTest is Test {
    Counter public counter;

    function setUp() public {
        counter = new Counter();
        counter.setNumber(0);
    }

    function testIncrement() public {
        counter.increment();
        assertEq(counter.number(), 1);
    }

    function testSetNumber(uint256 x) public {
        counter.setNumber(x);
        assertEq(counter.number(), x);
    }
}

This file performs unit testing on the contract we created in the previous section. Here's what the test is doing:

  • The contract includes a public "Counter" type variable called "counter". In the setUp function, it initializes a new instance of the "Counter" contract and sets the "number" variable to 0.

  • There are two test functions in the contract: testIncrement and testSetNumber.

  • The testIncrement function tests the "increment" function of the "Counter" contract by calling it and then asserting that the "number" in the "Counter" contract is 1. It verifies if the increment operation correctly increases the number by one.

  • The testSetNumber function is more generic. It takes an unsigned integer argument 'x' and tests the "setNumber" function of the "Counter" contract. After calling the "setNumber" function with 'x', it asserts that the "number" in the "Counter" contract is equal to 'x'. This verifies that the "setNumber" function correctly updates the "number" in the "Counter" contract.

Now, to test your code, run the following:

bash
forge test
forge test

If the test is successful, your output should be similar to this:

bash
[⠆] Compiling...
No files changed, compilation skipped

Running 2 tests for test/Counter.t.sol:CounterTest
[PASS] testIncrement() (gas: 28334)
[PASS] testSetNumber(uint256) (runs: 256, μ: 27709, ~: 28409)
Test result: ok. 2 passed; 0 failed; finished in 8.96ms
[⠆] Compiling...
No files changed, compilation skipped

Running 2 tests for test/Counter.t.sol:CounterTest
[PASS] testIncrement() (gas: 28334)
[PASS] testSetNumber(uint256) (runs: 256, μ: 27709, ~: 28409)
Test result: ok. 2 passed; 0 failed; finished in 8.96ms

Deploying your smart contract ​

Using Anvil ​

First, we'll test out our contract on a local devnet called "anvil". To start the local server, run:

bash
anvil
anvil

You'll see a local RPC endpoint (127.0.0.1:8545) and accounts to test with.

Let's deploy the contract now. First, set a private key from anvil:

bash
export PRIVATE_KEY=0xac0974bec39a17e36ba4a6b4d238ff944bacb478cbed5efcae784d7bf4f2ff80
export ANVIL_RPC_URL=http://localhost:8545
export PRIVATE_KEY=0xac0974bec39a17e36ba4a6b4d238ff944bacb478cbed5efcae784d7bf4f2ff80
export ANVIL_RPC_URL=http://localhost:8545

Now, deploy the contract:

bash
forge create --rpc-url $ANVIL_RPC_URL \
--private-key $PRIVATE_KEY \
src/Counter.sol:Counter
forge create --rpc-url $ANVIL_RPC_URL \
--private-key $PRIVATE_KEY \
src/Counter.sol:Counter

Using Bubs ​

First, set a private key from your funded Ethereum wallet and set the BUBS_RPC_URL variable with an RPC of your choosing:

bash
export BUBS_PRIVATE_KEY=0xac0974bec39a17e36ba4a6b4d238ff944bacb478cbed5efcae784d7bf4f2ff80
export BUBS_RPC_URL=https://bubs-sepolia.rpc.caldera.xyz/http
export BUBS_PRIVATE_KEY=0xac0974bec39a17e36ba4a6b4d238ff944bacb478cbed5efcae784d7bf4f2ff80
export BUBS_RPC_URL=https://bubs-sepolia.rpc.caldera.xyz/http

Now that we're ready to deploy the smart contract onto Bubs, we will run the forge create command.

bash
forge create --rpc-url $BUBS_RPC_URL \
--private-key $BUBS_PRIVATE_KEY \
src/Counter.sol:Counter
forge create --rpc-url $BUBS_RPC_URL \
--private-key $BUBS_PRIVATE_KEY \
src/Counter.sol:Counter

A successful deployment will return output similar to below:

bash
[⠆] Compiling...
No files changed, compilation skipped
Deployer: 0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266
Deployed to: 0x5FbDB2315678afecb367f032d93F642f64180aa3
Transaction hash: 0xf1a793a793cd9fc588f5132d99008565ea361eb3535d66499575e9e1908200b2
[⠆] Compiling...
No files changed, compilation skipped
Deployer: 0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266
Deployed to: 0x5FbDB2315678afecb367f032d93F642f64180aa3
Transaction hash: 0xf1a793a793cd9fc588f5132d99008565ea361eb3535d66499575e9e1908200b2

Once you've deployed the contract, you're ready to interact with it!

First, we'll set it as a variable:

bash
export CONTRACT_ADDRESS=0x5FbDB2315678afecb367f032d93F642f64180aa3
export CONTRACT_ADDRESS=0x5FbDB2315678afecb367f032d93F642f64180aa3

Interacting with your smart contract ​

Foundry uses cast, a CLI for performing Ethereum RPC calls.

To write to the contract, we'll use the cast send command:

bash
cast send $CONTRACT_ADDRESS "setNumber(uint256)" 10 --rpc-url $BUBS_RPC_URL --private-key $BUBS_PRIVATE_KEY
cast send $CONTRACT_ADDRESS "setNumber(uint256)" 10 --rpc-url $BUBS_RPC_URL --private-key $BUBS_PRIVATE_KEY

Your output will look similar:

bash
blockHash               0x131822bef6eb59656d7e1387c19b75be667e587006710365ec5cf58030786c42
blockNumber             3
contractAddress
cumulativeGasUsed       43494
effectiveGasPrice       3767182372
gasUsed                 43494
logs                    []
logsBloom               0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
root
status                  1
transactionHash         0x8f15d6004598f0662dd673a9898dceef77be8cc28408cecc284b28d7be32307d
transactionIndex        0
type                    2
blockHash               0x131822bef6eb59656d7e1387c19b75be667e587006710365ec5cf58030786c42
blockNumber             3
contractAddress
cumulativeGasUsed       43494
effectiveGasPrice       3767182372
gasUsed                 43494
logs                    []
logsBloom               0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
root
status                  1
transactionHash         0x8f15d6004598f0662dd673a9898dceef77be8cc28408cecc284b28d7be32307d
transactionIndex        0
type                    2

Now, we can make a read call to view the state of the number variable, using the cast call command:

bash
cast call $CONTRACT_ADDRESS "number()" --rpc-url $BUBS_RPC_URL
cast call $CONTRACT_ADDRESS "number()" --rpc-url $BUBS_RPC_URL

The result will look similar:

bash
0x000000000000000000000000000000000000000000000000000000000000000a
0x000000000000000000000000000000000000000000000000000000000000000a

Convert the result from hexadecimal to a base 10 value with:

bash
echo $((0x000000000000000000000000000000000000000000000000000000000000000a))
echo $((0x000000000000000000000000000000000000000000000000000000000000000a))

Next steps ​

Congratulations! You've learned how to deploy a smart contract to Bubs testnet.

What will you build next? Now, you're ready to check out the GM Portal tutorial.