curl -L https://foundry.paradigm.xyz | bash
then run
foundryup
- Now you have access to
forge --helpcastandanvil
forge init folderName
it will create some files and folders. The lib directory contains forge-std, a collection of helpful contracts for use with forge and foundry. the src folder contains the contracts test folder will be the place where we write all our tests and scripts folder for writing deploy scripts
Compile all contracts:
forge build
Install dependencies
forge install OpenZeppelin/openzeppelin-contracts
To run all tests type:
forge test
Run specific test file:
forge test -vv --match-path test/Template.t.sol
Run specific test:
forge test -m testSetNumber
Skip specific test:
forge test -vv --match-path test/TemplateTest.t.sol --no-match-test testForkingAndSendingUSDC
Please note - You will get one test failure. Please ignore. We will be looking into it after some time
Some assertion statement that can be used in the tests are
- assertEq
- assertTrue
- assertEqDecimal
- assertGt, assertGe, assertLt, assertLe - greater than, greater than equal to, less than, less than equal to and many more. Others can be found here
Foundry also support fuzzing. the testSetNumber() function is an example of this.
We can also log using foundry. We may use the following log, log_uint, log_address, log_string, or log_named_string. You may find a lot more here
The default behavior for forge test is to only display a summary of passing and failing tests. You can control this behavior by increasing the verbosity (using the -v flag). Each level of verbosity adds more information:
- Level 2 (-vv): Logs emitted during tests are also displayed. That includes assertion errors from tests, showing information such as expected vs actual.
- Level 3 (-vvv): Stack traces for failing tests are also displayed.
- Level 4 (-vvvv): Stack traces for all tests are displayed, and setup traces for failing tests are displayed.
- Level 5 (-vvvvv): Stack traces and setup traces are always displayed.
forge test -vv
Start the native Foundry local development blockchain
anvil
See all available flags to pass in
anvil -help
Deploy using --broadcast and simulate deployment without using --broadcast Use http://localhost:8545 to deploy locally or https://eth-goerli.g.alchemy.com/v2/yourAlchemyKey to deploy on goerli
forge script script/Counter.s.sol:CounterScript --fork-url http://localhost:8545 --private-key INPUT_PRIVATE_KEY_HERE --broadcast
--broadcast will show the transaction logs on the terminal
Alternatively, You can also deploy a contract without any scripts by using forge create
forge create --rpc-url http://localhost:8545 --private-key INPUT_PRIVATE_KEY_HERE src/Counter.sol:Counter --constructor-args 1
- First fork mainnet if you want to make calls there or Goerli like this
cast call --rpc-url=ActualGoerliURL contractAddress "decimals()(uint256)" --private-key=actualValue
Perform Ethereum RPC calls from the comfort of your command line.
cast call contractAddress "number()(uint256)"
This command fetches the value of number.
The following command sets a new number for the variable number
cast send contractAddress "setNumber(uint256)" "28" --private-key INPUT_PRIVATE_KEY_HERE
To send ether along with the transaction, you can use the --value .For example:-
cast send <ContractAddress> "donate()" --value 1ether --private-key <Prvt-key>
you can also include values like 10gwei, 0.01ether etc...
There are a lot of cheatcodes that we can use and all of them can be found here
In this tutorial we are using specifically 2 cheatcodes in the test file, namely expectRevert and prank
- expectRevert: This will expect a revert to happen
- prank: this command will let us change the address of the person sending the transaction
Please refer the function testIncrementWithOtherAccount() in Counter.t.sol file to find the implementation.
To fork the mainnet, you may use the command
anvil --fork-url [ALCHEMY_OR_INFURA_KEY]
You may use the vm.prank to impersonate the account in your test.
Kindly check the testForkingAndSendingUSDC() example in the test file to see an implementation. Here we are simply sending some USDC from a whale account to an address.
Now simply running the forge test will give you an error since there is no USDC contract in our local blockchain.
So we need to fork the mainnet while running the test, to do that, just use the below command:
forge test --rpc-url https://eth-mainnet.g.alchemy.com/v2/<ETH_ALCHEMY> -vv
-vv was added just to output the logs
To run the debugger on specific functions in the test file: just run
forge script ./test/Counter.t.sol:CounterTest --sig "testIncrement()" --debug
When the debugger is run, you are presented with a terminal divided into four quadrants:
- Quadrant 1: The opcodes in the debugging session, with the current opcode highlighted. Additionally, the address of the current account, the program counter and the accumulated gas usage is also displayed
- Quadrant 2: The current stack, as well as the size of the stack
- Quadrant 3: The source program view
- Quadrant 4: The current memory of the EVM
To change the netoworks, simply add the --rpc-url as [ALCHEMY OR INFURA URL] of your required network when executing commands like forge test, forge create
- Foundry Docs
- Foundry Tutorial by James Bachini
- Smart Contract Development with Foundry by Nader Dabit
Add --verify upon deployment
forge create --rpc-url http://localhost:8545 --private-key INPUT_PRIVATE_KEY_HERE src/Counter.sol:Counter --constructor-args 1 --verify
or verify already preexisting contract:
forge verify-contract <ADDRESS> <CONTRACT> <ETHERSCAN_KEY>
example:
forge verify-contract 0x9fd7A2eB88cd2981f252114a870BB38805b9806c src/SmartWalletFactoryV2.sol:SmartWalletFactoryV2 FQFVHWRK2PFGHCR296BENZQYW88N39REHE