Foundry Book

forge snapshot

NAME

forge-snapshot - Create a snapshot of each test’s gas usage.

DESCRIPTION

Create a snapshot of each test’s gas usage.

The results are written to a file named .gas-snapshot. You can change the name of the file by passing --snap <PATH>.

Fuzz tests are included by default in the snapshot. They use a static seed to achieve deterministic results.

Snapshots can be compared with --diff and --check. The first flag will output a diff, and the second will output a diff and exit with code 1 if the snapshots do not match.

OPTIONS

Snapshot Options

--asc
Sort results by gas used (ascending).

--desc
Sort results by gas used (descending).

--min min_gas
Only include tests that used more gas that the given amount.

--max max_gas
Only include tests that used less gas that the given amount.

--tolerance threshold
Tolerates gas deviations up to the specified percentage (0-100).

--diff path
Output a diff against a pre-existing snapshot.

By default the comparison is done with .gas-snapshot.

--check path
Compare against a pre-existing snapshot, exiting with code 1 if they do not match.

Outputs a diff if the snapshots do not match.

By default the comparison is done with .gas-snapshot.

--snap path
Output file for the snapshot. Default: .gas-snapshot.

Test Options

-m regex
--match regex
Only run test functions matching the specified regex pattern.
Deprecated: See --match-test.

--match-test regex
Only run test functions matching the specified regex pattern.

--no-match-test regex
Only run test functions that do not match the specified regex pattern.

--match-contract regex
Only run tests in contracts matching the specified regex pattern.

--no-match-contract regex
Only run tests in contracts that do not match the specified regex pattern.

--match-path glob
Only run tests in source files matching the specified glob pattern.

--no-match-path glob
Only run tests in source files that do not match the specified glob pattern.

--debug regex
Run a test in the debugger.

The argument passed to this flag is the name of the test function you want to run, and it works the same as --match-test.

If more than one test matches your specified criteria, you must add additional filters until only one test is found (see --match-contract and --match-path).

The matching test will be opened in the debugger regardless of the outcome of the test.

If the matching test is a fuzz test, then it will open the debugger on the first failure case. If the fuzz test does not fail, it will open the debugger on the last fuzz case.

For more fine-grained control of which fuzz case is run, see forge debug.

--gas-report
Print a gas report.

--allow-failure
Exit with code 0 even if a test fails.

--fail-fast
Stop running tests after the first failure.

--etherscan-api-key key
Etherscan API key. If set, traces are decoded using Etherscan if --fork-url is also set.
Environment: ETHERSCAN_API_KEY

EVM Options

-f url
--rpc-url url
--fork-url url
Fetch state over a remote endpoint instead of starting from an empty state.

If you want to fetch state from a specific block number, see --fork-block-number.

--fork-block-number block
Fetch state from a specific block number over a remote endpoint. See --fork-url.

--fork-retry-backoff <BACKOFF>
Initial retry backoff on encountering errors.

--no-storage-caching
Explicitly disables the use of RPC caching.

All storage slots are read entirely from the endpoint. See --fork-url.

-v
--verbosity
Verbosity of the EVM.

Pass multiple times to increase the verbosity (e.g. -v, -vv, -vvv).

    Verbosity levels:
    - 2: Print logs for all tests
    - 3: Print execution traces for failing tests
    - 4: Print execution traces for all tests, and setup traces for failing tests
    - 5: Print execution and setup traces for all tests

--sender address
The address which will be executing tests

--initial-balance balance
The initial balance of deployed contracts

--ffi
Enables the FFI cheatcode

Executor Options

--base-fee <FEE>
--block-base-fee-per-gas <FEE>
The base fee in a block (in wei).

--block-coinbase address
The coinbase of the block.

--block-difficulty difficulty
The block difficulty.

--block-gas-limit gas_limit
The block gas limit.

--block-number block
The block number.

--block-timestamp timestamp
The timestamp of the block (in seconds).

--chain-id chain_id
The chain ID.

--gas-limit gas_limit
The block gas limit.

--gas-price gas_price
The gas price (in wei).

--tx-origin address
The transaction origin.

Cache Options

--force
Clear the cache and artifacts folder and recompile.

Linker Options

--libraries libraries
Set pre-linked libraries.

The parameter must be in the format <remapped path to lib>:<library name>:<address>, e.g. src/Contract.sol:Library:0x....

Can also be set in your configuration file as libraries = ["<path>:<lib name>:<address>"].

Compiler Options

--optimize
Activate the Solidity optimizer.

--optimizer-runs runs
The number of optimizer runs.

--via-ir
Use the Yul intermediate representation compilation pipeline.

--revert-strings
How to treat revert and require reason strings.

--use solc_version
Specify the solc version, or a path to a local solc, to build with.

Valid values are in the format x.y.z, solc:x.y.z or path/to/solc.

--offline
Do not access the network. Missing solc versions will not be installed.

--no-auto-detect
Do not auto-detect solc.

--ignored-error-codes error_codes
Ignore solc warnings by error code. The parameter is a comma-separated list of error codes.

--extra-output selector
Extra output to include in the contract's artifact.

Example keys: abi, storageLayout, evm.assembly, ewasm, ir, ir-optimized, metadata.

For a full description, see the Solidity docs.

--extra-output-files selector
Extra output to write to separate files.

Example keys: abi, storageLayout, evm.assembly, ewasm, ir, ir-optimized, metadata.

For a full description, see the Solidity docs.

--evm-version version
The target EVM version.

Project Options

--build-info
Generate build info files.

--build-info-path path
Output path to directory that build info files will be written to.

--root path
The project's root path. By default, this is the root directory of the current git repository, or the current working directory.

-C path
--contracts path
The contracts source directory.
Environment: DAPP_SRC

--lib-paths path
The path to the library folder.

-R remappings
--remappings remappings
The project's remappings.

The parameter is a comma-separated list of remappings in the format <source>=<dest>.

--cache-path path
The path to the compiler cache.

--config-path file
Path to the config file.

--hh
--hardhat
This is a convenience flag, and is the same as passing --contracts contracts --lib-paths node-modules.

-o path
--out path
The project's artifacts directory.

--silent
Suppress all output.

Create a snapshot:
```
forge snapshot
```
Generate a diff:
```
forge snapshot --diff
```
Check that the snapshots match:
```
forge snapshot --check
```