Cheatcodes Reference
Cheatcodes give you powerful assertions, the ability to alter the state of the EVM, mock data, and more.
Cheatcodes are made available through use of the cheatcode address (0x7109709ECfa91a80626fF3989D68f67F5b1DD12D).
ℹ️ Note
If you encounter errors for this address when using fuzzed addresses in your tests, you may wish to exclude it from your fuzz tests by using the following line:
vm.assume(address_ != 0x7109709ECfa91a80626fF3989D68f67F5b1DD12D);
You can also access cheatcodes easily via vm available in Forge Standard Library's Test contract.
Forge Standard Library Cheatcodes
Forge Std implements wrappers around cheatcodes, which combine multiple standard cheatcodes to improve development experience. These are not technically cheatcodes, but rather compositions of Forge's cheatcodes.
You can view the list of Forge Standard Library's cheatcode wrappers in the references section. You can reference the Forge Std source code to learn more about how the wrappers work under the hood.
Cheatcode Types
Below are some subsections for the different Forge cheatcodes.
- Environment: Cheatcodes that alter the state of the EVM.
- Assertions: Cheatcodes that are powerful assertions
- Fuzzer: Cheatcodes that configure the fuzzer
- External: Cheatcodes that interact with external state (files, commands, ...)
- Utilities: Smaller utility cheatcodes
- Forking: Forking mode cheatcodes
- Snapshots: Snapshot cheatcodes
Cheatcodes Interface
This is a Solidity interface for all of the cheatcodes present in Forge.
interface CheatCodes {
// This allows us to getRecordedLogs()
struct Log {bytes32[] topics; bytes data;}
// Set block.timestamp
function warp(uint256) external;
// Set block.number
function roll(uint256) external;
// Set block.basefee
function fee(uint256) external;
// Set block.chainid
function chainId(uint256) external;
// Loads a storage slot from an address
function load(address account, bytes32 slot) external returns (bytes32);
// Stores a value to an address' storage slot
function store(address account, bytes32 slot, bytes32 value) external;
// Signs data
function sign(uint256 privateKey, bytes32 digest) external returns (uint8 v, bytes32 r, bytes32 s);
// Computes address for a given private key
function addr(uint256 privateKey) external returns (address);
// Gets the nonce of an account
function getNonce(address account) external returns (uint64);
// Sets the nonce of an account
// The new nonce must be higher than the current nonce of the account
function setNonce(address account, uint64 nonce) external;
// Performs a foreign function call via terminal
function ffi(string[] calldata) external returns (bytes memory);
// Set environment variables, (name, value)
function setEnv(string calldata, string calldata) external;
// Read environment variables, (name) => (value)
function envBool(string calldata) external returns (bool);
function envUint(string calldata) external returns (uint256);
function envInt(string calldata) external returns (int256);
function envAddress(string calldata) external returns (address);
function envBytes32(string calldata) external returns (bytes32);
function envString(string calldata) external returns (string memory);
function envBytes(string calldata) external returns (bytes memory);
// Read environment variables as arrays, (name, delim) => (value[])
function envBool(string calldata, string calldata) external returns (bool[] memory);
function envUint(string calldata, string calldata) external returns (uint256[] memory);
function envInt(string calldata, string calldata) external returns (int256[] memory);
function envAddress(string calldata, string calldata) external returns (address[] memory);
function envBytes32(string calldata, string calldata) external returns (bytes32[] memory);
function envString(string calldata, string calldata) external returns (string[] memory);
function envBytes(string calldata, string calldata) external returns (bytes[] memory);
// Sets the *next* call's msg.sender to be the input address
function prank(address) external;
// Sets all subsequent calls' msg.sender to be the input address until `stopPrank` is called
function startPrank(address) external;
// Sets the *next* call's msg.sender to be the input address, and the tx.origin to be the second input
function prank(address, address) external;
// Sets all subsequent calls' msg.sender to be the input address until `stopPrank` is called, and the tx.origin to be the second input
function startPrank(address, address) external;
// Resets subsequent calls' msg.sender to be `address(this)`
function stopPrank() external;
// Sets an address' balance
function deal(address who, uint256 newBalance) external;
// Sets an address' code
function etch(address who, bytes calldata code) external;
// Expects an error on next call
function expectRevert() external;
function expectRevert(bytes calldata) external;
function expectRevert(bytes4) external;
// Record all storage reads and writes
function record() external;
// Gets all accessed reads and write slot from a recording session, for a given address
function accesses(address) external returns (bytes32[] memory reads, bytes32[] memory writes);
// Record all the transaction logs
function recordLogs() external;
// Gets all the recorded logs
function getRecordedLogs() external returns (Log[] memory);
// Prepare an expected log with (bool checkTopic1, bool checkTopic2, bool checkTopic3, bool checkData).
// Call this function, then emit an event, then call a function. Internally after the call, we check if
// logs were emitted in the expected order with the expected topics and data (as specified by the booleans)
// Second form also checks supplied address against emitting contract.
function expectEmit(bool, bool, bool, bool) external;
function expectEmit(bool, bool, bool, bool, address) external;
// Mocks a call to an address, returning specified data.
// Calldata can either be strict or a partial match, e.g. if you only
// pass a Solidity selector to the expected calldata, then the entire Solidity
// function will be mocked.
function mockCall(address, bytes calldata, bytes calldata) external;
// Clears all mocked calls
function clearMockedCalls() external;
// Expect a call to an address with the specified calldata.
// Calldata can either be strict or a partial match
function expectCall(address, bytes calldata) external;
// Gets the bytecode for a contract in the project given the path to the contract.
function getCode(string calldata) external returns (bytes memory);
// Label an address in test traces
function label(address addr, string calldata label) external;
// When fuzzing, generate new inputs if conditional not met
function assume(bool) external;
// Set block.coinbase (who)
function coinbase(address) external;
// Using the address that calls the test contract or the address provided
// as the sender, has the next call (at this call depth only) create a
// transaction that can later be signed and sent onchain
function broadcast() external;
function broadcast(address) external;
// Using the address that calls the test contract or the address provided
// as the sender, has all subsequent calls (at this call depth only) create
// transactions that can later be signed and sent onchain
function startBroadcast() external;
function startBroadcast(address) external;
// Stops collecting onchain transactions
function stopBroadcast() external;
// Snapshot the current state of the evm.
// Returns the id of the snapshot that was created.
// To revert a snapshot use `revertTo`
function snapshot() external returns(uint256);
// Revert the state of the evm to a previous snapshot
// Takes the snapshot id to revert to.
// This deletes the snapshot and all snapshots taken after the given snapshot id.
function revertTo(uint256) external returns(bool);
// Creates a new fork with the given endpoint and block and returns the identifier of the fork
function createFork(string calldata,uint256) external returns(uint256);
// Creates a new fork with the given endpoint and the _latest_ block and returns the identifier of the fork
function createFork(string calldata) external returns(uint256);
// Creates _and_ also selects a new fork with the given endpoint and block and returns the identifier of the fork
function createSelectFork(string calldata,uint256) external returns(uint256);
// Creates _and_ also selects a new fork with the given endpoint and the latest block and returns the identifier of the fork
function createSelectFork(string calldata) external returns(uint256);
// Takes a fork identifier created by `createFork` and sets the corresponding forked state as active.
function selectFork(uint256) external;
// Returns the currently active fork
// Reverts if no fork is currently active
function activeFork() external returns(uint256);
// Updates the currently active fork to given block number
// This is similar to `roll` but for the currently active fork
function rollFork(uint256) external;
// Updates the given fork to given block number
function rollFork(uint256 forkId, uint256 blockNumber) external;
// Marks that the account(s) should use persistent storage across fork swaps in a multifork setup
// Meaning, changes made to the state of this account will be kept when switching forks
function makePersistent(address) external;
function makePersistent(address, address) external;
function makePersistent(address, address, address) external;
function makePersistent(address[] calldata) external;
// Revokes persistent status from the address, previously added via `makePersistent`
function revokePersistent(address) external;
function revokePersistent(address[] calldata) external;
// Returns true if the account is marked as persistent
function isPersistent(address) external returns (bool);
/// Returns the RPC url for the given alias
function rpcUrl(string calldata) external returns(string memory);
/// Returns all rpc urls and their aliases `[alias, url][]`
function rpcUrls() external returns(string[2][] memory);
}