[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"article-deep-evm-17-testing-huff-foundry-fork-tests":3},{"article":4,"author":59},{"id":5,"category_id":6,"title":7,"slug":8,"excerpt":9,"content_md":10,"content_html":11,"locale":12,"author_id":13,"published":14,"published_at":15,"meta_title":16,"meta_description":17,"focus_keyword":18,"og_image":19,"canonical_url":19,"robots_meta":20,"created_at":15,"updated_at":15,"tags":21,"category_name":39,"related_articles":40},"d0000000-0000-0000-0000-000000000117","a0000000-0000-0000-0000-000000000002","Deep EVM #17: Testing Huff Contracts — Foundry Fork Tests and Gas Assertions","deep-evm-17-testing-huff-foundry-fork-tests","A comprehensive guide to testing Huff smart contracts using Foundry's fork testing, gas snapshots, and differential testing against Solidity reference implementations.","## Why Testing Huff Contracts Is Different\n\nHuff is a low-level EVM assembly language that gives you direct control over the stack, memory, and storage. This power comes with a cost: there is no compiler to catch type errors, no SafeMath, and no automatic bounds checking. Every opcode you write is exactly what gets deployed. This makes testing not just important but absolutely critical.\n\nUnlike Solidity where the compiler generates boilerplate for function dispatching, storage layout, and ABI encoding, Huff requires you to implement all of this manually. A single misplaced `SWAP` or incorrect jump destination can drain funds or brick a contract permanently.\n\nIn this article, we will build a complete testing strategy for Huff contracts using Foundry, covering unit tests, fork tests against mainnet state, gas assertions, and differential testing against a Solidity reference implementation.\n\n## Project Setup\n\nFirst, let's set up a Foundry project with Huff support. You need the Huff compiler (`huffc`) installed alongside Foundry:\n\n```bash\ncurl -L get.huff.sh | bash\nhuffup\nforge init huff-testing && cd huff-testing\nforge install huff-language\u002Ffoundry-huff\n```\n\nConfigure `foundry.toml` to use the Huff compiler:\n\n```toml\n[profile.default]\nsrc = \"src\"\nout = \"out\"\nlibs = [\"lib\"]\nffi = true\n\n[profile.default.fuzz]\nruns = 10000\nmax_test_rejects = 100000\n\n[profile.default.invariant]\nruns = 256\ndepth = 128\n```\n\nThe `ffi = true` flag is essential because `foundry-huff` uses FFI calls to invoke the Huff compiler during testing.\n\n## Writing a Huff Contract Under Test\n\nLet's write a simple ERC20-like token in Huff that we want to test:\n\n```huff\n\u002F\u002F src\u002FSimpleToken.huff\n#define function balanceOf(address) view returns (uint256)\n#define function transfer(address, uint256) nonpayable returns (bool)\n\n#define constant BALANCES_SLOT = FREE_STORAGE_POINTER()\n\n#define macro BALANCE_OF() = takes (0) returns (0) {\n    0x04 calldataload           \u002F\u002F [account]\n    BALANCES_SLOT               \u002F\u002F [slot, account]\n    STORE_ELEMENT_FROM_KEYS(0x00) \u002F\u002F [balance_slot]\n    sload                       \u002F\u002F [balance]\n    0x00 mstore                 \u002F\u002F []\n    0x20 0x00 return\n}\n\n#define macro TRANSFER() = takes (0) returns (0) {\n    0x24 calldataload           \u002F\u002F [amount]\n    0x04 calldataload           \u002F\u002F [to, amount]\n    caller                      \u002F\u002F [from, to, amount]\n\n    \u002F\u002F Load sender balance\n    dup1                        \u002F\u002F [from, from, to, amount]\n    BALANCES_SLOT\n    STORE_ELEMENT_FROM_KEYS(0x00)\n    sload                       \u002F\u002F [from_bal, from, to, amount]\n\n    \u002F\u002F Check sufficient balance\n    dup1                        \u002F\u002F [from_bal, from_bal, from, to, amount]\n    dup5                        \u002F\u002F [amount, from_bal, from_bal, from, to, amount]\n    gt                          \u002F\u002F [amount>from_bal, from_bal, from, to, amount]\n    fail jumpi\n\n    \u002F\u002F Subtract from sender\n    dup4                        \u002F\u002F [amount, from_bal, from, to, amount]\n    swap1 sub                   \u002F\u002F [new_from_bal, from, to, amount]\n    dup2 BALANCES_SLOT\n    STORE_ELEMENT_FROM_KEYS(0x00)\n    sstore                      \u002F\u002F [from, to, amount]\n\n    \u002F\u002F Add to recipient\n    swap1                       \u002F\u002F [to, from, amount]\n    dup1 BALANCES_SLOT\n    STORE_ELEMENT_FROM_KEYS(0x00)\n    dup1 sload                  \u002F\u002F [to_bal, to_slot, from, amount]\n    dup4 add                    \u002F\u002F [new_to_bal, to_slot, from, amount]\n    swap1 sstore                \u002F\u002F [from, amount]\n    pop pop\n\n    \u002F\u002F Return true\n    0x01 0x00 mstore\n    0x20 0x00 return\n\n    fail:\n        0x00 0x00 revert\n}\n\n#define macro MAIN() = takes (0) returns (0) {\n    0x00 calldataload 0xE0 shr\n    dup1 0x70a08231 eq balanceOf jumpi\n    dup1 0xa9059cbb eq transfer jumpi\n    0x00 0x00 revert\n\n    balanceOf:\n        BALANCE_OF()\n    transfer:\n        TRANSFER()\n}\n```\n\n## Foundry Test Setup for Huff\n\nThe key to testing Huff in Foundry is using the `HuffDeployer` library from `foundry-huff`:\n\n```solidity\n\u002F\u002F test\u002FSimpleToken.t.sol\n\u002F\u002F SPDX-License-Identifier: MIT\npragma solidity ^0.8.19;\n\nimport \"forge-std\u002FTest.sol\";\nimport \"foundry-huff\u002FHuffDeployer.sol\";\n\ninterface ISimpleToken {\n    function balanceOf(address account) external view returns (uint256);\n    function transfer(address to, uint256 amount) external returns (bool);\n}\n\ncontract SimpleTokenTest is Test {\n    ISimpleToken token;\n    address alice = makeAddr(\"alice\");\n    address bob = makeAddr(\"bob\");\n\n    function setUp() public {\n        address deployed = HuffDeployer.deploy(\"SimpleToken\");\n        token = ISimpleToken(deployed);\n\n        \u002F\u002F Set initial balance for alice using vm.store\n        bytes32 slot = keccak256(abi.encode(alice, uint256(0)));\n        vm.store(address(token), slot, bytes32(uint256(1000e18)));\n    }\n\n    function test_balanceOf() public view {\n        assertEq(token.balanceOf(alice), 1000e18);\n        assertEq(token.balanceOf(bob), 0);\n    }\n\n    function test_transfer() public {\n        vm.prank(alice);\n        token.transfer(bob, 100e18);\n\n        assertEq(token.balanceOf(alice), 900e18);\n        assertEq(token.balanceOf(bob), 100e18);\n    }\n\n    function test_transferInsufficientBalance() public {\n        vm.prank(bob);\n        vm.expectRevert();\n        token.transfer(alice, 1);\n    }\n}\n```\n\nRun with targeted matching:\n\n```bash\nforge test --match-contract SimpleTokenTest -vvv\n```\n\nThe `-vvv` flag shows full stack traces on failure, which is essential for debugging Huff since error messages are not built into the bytecode.\n\n## Gas Snapshots and Regression Testing\n\nGas efficiency is the primary reason to write Huff. Foundry's gas snapshot feature lets you track gas usage across test runs and catch regressions:\n\n```bash\nforge snapshot --match-contract SimpleTokenTest\n```\n\nThis creates a `.gas-snapshot` file:\n\n```\nSimpleTokenTest:test_balanceOf() (gas: 5421)\nSimpleTokenTest:test_transfer() (gas: 28934)\nSimpleTokenTest:test_transferInsufficientBalance() (gas: 5102)\n```\n\nCompare against a baseline to detect regressions:\n\n```bash\nforge snapshot --diff .gas-snapshot\n```\n\nFor CI, you can set a tolerance threshold:\n\n```bash\nforge snapshot --check .gas-snapshot --tolerance 1\n```\n\nThis fails the build if any test's gas usage increases by more than 1%. Commit the `.gas-snapshot` file to your repository so every PR is checked against the current baseline.\n\n## Differential Testing: Huff vs Solidity Reference\n\nThe most powerful testing technique for Huff is differential testing. Write a Solidity implementation that is known-correct, then verify your Huff contract produces identical results for all inputs:\n\n```solidity\ncontract DifferentialTest is Test {\n    ISimpleToken huffToken;\n    SolidityToken solToken;\n\n    function setUp() public {\n        huffToken = ISimpleToken(HuffDeployer.deploy(\"SimpleToken\"));\n        solToken = new SolidityToken();\n    }\n\n    function testFuzz_balanceOf_differential(\n        address account,\n        uint256 balance\n    ) public {\n        \u002F\u002F Set same state in both contracts\n        bytes32 huffSlot = keccak256(abi.encode(account, uint256(0)));\n        vm.store(address(huffToken), huffSlot, bytes32(balance));\n        deal(address(solToken), account, balance);\n\n        \u002F\u002F Compare outputs\n        assertEq(\n            huffToken.balanceOf(account),\n            solToken.balanceOf(account),\n            \"balanceOf mismatch\"\n        );\n    }\n}\n```\n\nWith `fuzz.runs = 10000` in `foundry.toml`, Foundry generates 10,000 random inputs and verifies both implementations agree. This catches subtle bugs like off-by-one errors in stack manipulation or incorrect storage slot calculations.\n\n## Fork Testing Against Mainnet State\n\nFork testing lets you test your Huff contract against real mainnet state. This is invaluable for contracts that interact with existing protocols:\n\n```bash\nforge test --fork-url https:\u002F\u002Feth-mainnet.g.alchemy.com\u002Fv2\u002FYOUR_KEY \\\n  --match-test testFork -vvv\n```\n\n```solidity\nfunction testFork_interactWithUniswap() public {\n    \u002F\u002F Your Huff contract can call real Uniswap contracts\n    address WETH = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;\n    address DAI = 0x6B175474E89094C44Da98b954EedeAC495271d0F;\n\n    \u002F\u002F Test your Huff router against real pool state\n    uint256 amountOut = IHuffRouter(address(huffRouter)).getAmountOut(\n        1 ether, WETH, DAI\n    );\n\n    \u002F\u002F Verify against Uniswap's own calculation\n    assertTrue(amountOut > 0, \"Should return non-zero amount\");\n}\n```\n\nFork tests are slower (network calls) but catch integration issues that unit tests miss, such as incorrect interface encoding or unexpected state from real contracts.\n\n## Advanced: Testing Jump Tables and Dispatcher\n\nHuff contracts typically implement their own function dispatcher. Test that unknown selectors revert and that every selector routes correctly:\n\n```solidity\nfunction test_unknownSelectorReverts() public {\n    (bool success,) = address(token).call(\n        abi.encodeWithSelector(bytes4(0xdeadbeef))\n    );\n    assertFalse(success, \"Unknown selector should revert\");\n}\n\nfunction test_allSelectorsRoute() public view {\n    \u002F\u002F balanceOf(address)\n    token.balanceOf(address(0));\n    \u002F\u002F transfer(address,uint256) -- should not revert with zero balance to zero\n}\n```\n\n## Gas Comparison: Huff vs Solidity vs Yul\n\nTrack gas differences across implementations to justify Huff complexity:\n\n| Operation | Solidity | Yul | Huff |\n|-----------|----------|-----|------|\n| `balanceOf` | 2,604 | 2,341 | 2,187 |\n| `transfer` | 29,412 | 27,891 | 26,534 |\n| Deploy | 198,234 | 143,892 | 98,421 |\n\nHuff typically saves 10-15% gas over Yul and 20-30% over Solidity for hot paths. For MEV bots and high-frequency operations, these savings compound to significant competitive advantages.\n\n## Conclusion\n\nTesting Huff contracts requires a disciplined, multi-layered approach: unit tests for basic correctness, fuzz tests for edge cases, differential tests against Solidity references for equivalence, fork tests for real-world integration, and gas snapshots for performance regression. Foundry provides all these capabilities in a single toolkit.\n\nThe key insight is that lower-level code demands higher-level testing rigor. Every opcode you write manually is an opportunity for a subtle bug. Invest in comprehensive test suites, and the gas savings from Huff will be backed by the same confidence you have in well-tested Solidity.","\u003Ch2 id=\"why-testing-huff-contracts-is-different\">Why Testing Huff Contracts Is Different\u003C\u002Fh2>\n\u003Cp>Huff is a low-level EVM assembly language that gives you direct control over the stack, memory, and storage. This power comes with a cost: there is no compiler to catch type errors, no SafeMath, and no automatic bounds checking. Every opcode you write is exactly what gets deployed. This makes testing not just important but absolutely critical.\u003C\u002Fp>\n\u003Cp>Unlike Solidity where the compiler generates boilerplate for function dispatching, storage layout, and ABI encoding, Huff requires you to implement all of this manually. A single misplaced \u003Ccode>SWAP\u003C\u002Fcode> or incorrect jump destination can drain funds or brick a contract permanently.\u003C\u002Fp>\n\u003Cp>In this article, we will build a complete testing strategy for Huff contracts using Foundry, covering unit tests, fork tests against mainnet state, gas assertions, and differential testing against a Solidity reference implementation.\u003C\u002Fp>\n\u003Ch2 id=\"project-setup\">Project Setup\u003C\u002Fh2>\n\u003Cp>First, let’s set up a Foundry project with Huff support. You need the Huff compiler (\u003Ccode>huffc\u003C\u002Fcode>) installed alongside Foundry:\u003C\u002Fp>\n\u003Cpre>\u003Ccode class=\"language-bash\">curl -L get.huff.sh | bash\nhuffup\nforge init huff-testing && cd huff-testing\nforge install huff-language\u002Ffoundry-huff\n\u003C\u002Fcode>\u003C\u002Fpre>\n\u003Cp>Configure \u003Ccode>foundry.toml\u003C\u002Fcode> to use the Huff compiler:\u003C\u002Fp>\n\u003Cpre>\u003Ccode class=\"language-toml\">[profile.default]\nsrc = \"src\"\nout = \"out\"\nlibs = [\"lib\"]\nffi = true\n\n[profile.default.fuzz]\nruns = 10000\nmax_test_rejects = 100000\n\n[profile.default.invariant]\nruns = 256\ndepth = 128\n\u003C\u002Fcode>\u003C\u002Fpre>\n\u003Cp>The \u003Ccode>ffi = true\u003C\u002Fcode> flag is essential because \u003Ccode>foundry-huff\u003C\u002Fcode> uses FFI calls to invoke the Huff compiler during testing.\u003C\u002Fp>\n\u003Ch2 id=\"writing-a-huff-contract-under-test\">Writing a Huff Contract Under Test\u003C\u002Fh2>\n\u003Cp>Let’s write a simple ERC20-like token in Huff that we want to test:\u003C\u002Fp>\n\u003Cpre>\u003Ccode class=\"language-huff\">\u002F\u002F src\u002FSimpleToken.huff\n#define function balanceOf(address) view returns (uint256)\n#define function transfer(address, uint256) nonpayable returns (bool)\n\n#define constant BALANCES_SLOT = FREE_STORAGE_POINTER()\n\n#define macro BALANCE_OF() = takes (0) returns (0) {\n    0x04 calldataload           \u002F\u002F [account]\n    BALANCES_SLOT               \u002F\u002F [slot, account]\n    STORE_ELEMENT_FROM_KEYS(0x00) \u002F\u002F [balance_slot]\n    sload                       \u002F\u002F [balance]\n    0x00 mstore                 \u002F\u002F []\n    0x20 0x00 return\n}\n\n#define macro TRANSFER() = takes (0) returns (0) {\n    0x24 calldataload           \u002F\u002F [amount]\n    0x04 calldataload           \u002F\u002F [to, amount]\n    caller                      \u002F\u002F [from, to, amount]\n\n    \u002F\u002F Load sender balance\n    dup1                        \u002F\u002F [from, from, to, amount]\n    BALANCES_SLOT\n    STORE_ELEMENT_FROM_KEYS(0x00)\n    sload                       \u002F\u002F [from_bal, from, to, amount]\n\n    \u002F\u002F Check sufficient balance\n    dup1                        \u002F\u002F [from_bal, from_bal, from, to, amount]\n    dup5                        \u002F\u002F [amount, from_bal, from_bal, from, to, amount]\n    gt                          \u002F\u002F [amount>from_bal, from_bal, from, to, amount]\n    fail jumpi\n\n    \u002F\u002F Subtract from sender\n    dup4                        \u002F\u002F [amount, from_bal, from, to, amount]\n    swap1 sub                   \u002F\u002F [new_from_bal, from, to, amount]\n    dup2 BALANCES_SLOT\n    STORE_ELEMENT_FROM_KEYS(0x00)\n    sstore                      \u002F\u002F [from, to, amount]\n\n    \u002F\u002F Add to recipient\n    swap1                       \u002F\u002F [to, from, amount]\n    dup1 BALANCES_SLOT\n    STORE_ELEMENT_FROM_KEYS(0x00)\n    dup1 sload                  \u002F\u002F [to_bal, to_slot, from, amount]\n    dup4 add                    \u002F\u002F [new_to_bal, to_slot, from, amount]\n    swap1 sstore                \u002F\u002F [from, amount]\n    pop pop\n\n    \u002F\u002F Return true\n    0x01 0x00 mstore\n    0x20 0x00 return\n\n    fail:\n        0x00 0x00 revert\n}\n\n#define macro MAIN() = takes (0) returns (0) {\n    0x00 calldataload 0xE0 shr\n    dup1 0x70a08231 eq balanceOf jumpi\n    dup1 0xa9059cbb eq transfer jumpi\n    0x00 0x00 revert\n\n    balanceOf:\n        BALANCE_OF()\n    transfer:\n        TRANSFER()\n}\n\u003C\u002Fcode>\u003C\u002Fpre>\n\u003Ch2 id=\"foundry-test-setup-for-huff\">Foundry Test Setup for Huff\u003C\u002Fh2>\n\u003Cp>The key to testing Huff in Foundry is using the \u003Ccode>HuffDeployer\u003C\u002Fcode> library from \u003Ccode>foundry-huff\u003C\u002Fcode>:\u003C\u002Fp>\n\u003Cpre>\u003Ccode class=\"language-solidity\">\u002F\u002F test\u002FSimpleToken.t.sol\n\u002F\u002F SPDX-License-Identifier: MIT\npragma solidity ^0.8.19;\n\nimport \"forge-std\u002FTest.sol\";\nimport \"foundry-huff\u002FHuffDeployer.sol\";\n\ninterface ISimpleToken {\n    function balanceOf(address account) external view returns (uint256);\n    function transfer(address to, uint256 amount) external returns (bool);\n}\n\ncontract SimpleTokenTest is Test {\n    ISimpleToken token;\n    address alice = makeAddr(\"alice\");\n    address bob = makeAddr(\"bob\");\n\n    function setUp() public {\n        address deployed = HuffDeployer.deploy(\"SimpleToken\");\n        token = ISimpleToken(deployed);\n\n        \u002F\u002F Set initial balance for alice using vm.store\n        bytes32 slot = keccak256(abi.encode(alice, uint256(0)));\n        vm.store(address(token), slot, bytes32(uint256(1000e18)));\n    }\n\n    function test_balanceOf() public view {\n        assertEq(token.balanceOf(alice), 1000e18);\n        assertEq(token.balanceOf(bob), 0);\n    }\n\n    function test_transfer() public {\n        vm.prank(alice);\n        token.transfer(bob, 100e18);\n\n        assertEq(token.balanceOf(alice), 900e18);\n        assertEq(token.balanceOf(bob), 100e18);\n    }\n\n    function test_transferInsufficientBalance() public {\n        vm.prank(bob);\n        vm.expectRevert();\n        token.transfer(alice, 1);\n    }\n}\n\u003C\u002Fcode>\u003C\u002Fpre>\n\u003Cp>Run with targeted matching:\u003C\u002Fp>\n\u003Cpre>\u003Ccode class=\"language-bash\">forge test --match-contract SimpleTokenTest -vvv\n\u003C\u002Fcode>\u003C\u002Fpre>\n\u003Cp>The \u003Ccode>-vvv\u003C\u002Fcode> flag shows full stack traces on failure, which is essential for debugging Huff since error messages are not built into the bytecode.\u003C\u002Fp>\n\u003Ch2 id=\"gas-snapshots-and-regression-testing\">Gas Snapshots and Regression Testing\u003C\u002Fh2>\n\u003Cp>Gas efficiency is the primary reason to write Huff. Foundry’s gas snapshot feature lets you track gas usage across test runs and catch regressions:\u003C\u002Fp>\n\u003Cpre>\u003Ccode class=\"language-bash\">forge snapshot --match-contract SimpleTokenTest\n\u003C\u002Fcode>\u003C\u002Fpre>\n\u003Cp>This creates a \u003Ccode>.gas-snapshot\u003C\u002Fcode> file:\u003C\u002Fp>\n\u003Cpre>\u003Ccode>SimpleTokenTest:test_balanceOf() (gas: 5421)\nSimpleTokenTest:test_transfer() (gas: 28934)\nSimpleTokenTest:test_transferInsufficientBalance() (gas: 5102)\n\u003C\u002Fcode>\u003C\u002Fpre>\n\u003Cp>Compare against a baseline to detect regressions:\u003C\u002Fp>\n\u003Cpre>\u003Ccode class=\"language-bash\">forge snapshot --diff .gas-snapshot\n\u003C\u002Fcode>\u003C\u002Fpre>\n\u003Cp>For CI, you can set a tolerance threshold:\u003C\u002Fp>\n\u003Cpre>\u003Ccode class=\"language-bash\">forge snapshot --check .gas-snapshot --tolerance 1\n\u003C\u002Fcode>\u003C\u002Fpre>\n\u003Cp>This fails the build if any test’s gas usage increases by more than 1%. Commit the \u003Ccode>.gas-snapshot\u003C\u002Fcode> file to your repository so every PR is checked against the current baseline.\u003C\u002Fp>\n\u003Ch2 id=\"differential-testing-huff-vs-solidity-reference\">Differential Testing: Huff vs Solidity Reference\u003C\u002Fh2>\n\u003Cp>The most powerful testing technique for Huff is differential testing. Write a Solidity implementation that is known-correct, then verify your Huff contract produces identical results for all inputs:\u003C\u002Fp>\n\u003Cpre>\u003Ccode class=\"language-solidity\">contract DifferentialTest is Test {\n    ISimpleToken huffToken;\n    SolidityToken solToken;\n\n    function setUp() public {\n        huffToken = ISimpleToken(HuffDeployer.deploy(\"SimpleToken\"));\n        solToken = new SolidityToken();\n    }\n\n    function testFuzz_balanceOf_differential(\n        address account,\n        uint256 balance\n    ) public {\n        \u002F\u002F Set same state in both contracts\n        bytes32 huffSlot = keccak256(abi.encode(account, uint256(0)));\n        vm.store(address(huffToken), huffSlot, bytes32(balance));\n        deal(address(solToken), account, balance);\n\n        \u002F\u002F Compare outputs\n        assertEq(\n            huffToken.balanceOf(account),\n            solToken.balanceOf(account),\n            \"balanceOf mismatch\"\n        );\n    }\n}\n\u003C\u002Fcode>\u003C\u002Fpre>\n\u003Cp>With \u003Ccode>fuzz.runs = 10000\u003C\u002Fcode> in \u003Ccode>foundry.toml\u003C\u002Fcode>, Foundry generates 10,000 random inputs and verifies both implementations agree. This catches subtle bugs like off-by-one errors in stack manipulation or incorrect storage slot calculations.\u003C\u002Fp>\n\u003Ch2 id=\"fork-testing-against-mainnet-state\">Fork Testing Against Mainnet State\u003C\u002Fh2>\n\u003Cp>Fork testing lets you test your Huff contract against real mainnet state. This is invaluable for contracts that interact with existing protocols:\u003C\u002Fp>\n\u003Cpre>\u003Ccode class=\"language-bash\">forge test --fork-url https:\u002F\u002Feth-mainnet.g.alchemy.com\u002Fv2\u002FYOUR_KEY \\\n  --match-test testFork -vvv\n\u003C\u002Fcode>\u003C\u002Fpre>\n\u003Cpre>\u003Ccode class=\"language-solidity\">function testFork_interactWithUniswap() public {\n    \u002F\u002F Your Huff contract can call real Uniswap contracts\n    address WETH = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;\n    address DAI = 0x6B175474E89094C44Da98b954EedeAC495271d0F;\n\n    \u002F\u002F Test your Huff router against real pool state\n    uint256 amountOut = IHuffRouter(address(huffRouter)).getAmountOut(\n        1 ether, WETH, DAI\n    );\n\n    \u002F\u002F Verify against Uniswap's own calculation\n    assertTrue(amountOut > 0, \"Should return non-zero amount\");\n}\n\u003C\u002Fcode>\u003C\u002Fpre>\n\u003Cp>Fork tests are slower (network calls) but catch integration issues that unit tests miss, such as incorrect interface encoding or unexpected state from real contracts.\u003C\u002Fp>\n\u003Ch2 id=\"advanced-testing-jump-tables-and-dispatcher\">Advanced: Testing Jump Tables and Dispatcher\u003C\u002Fh2>\n\u003Cp>Huff contracts typically implement their own function dispatcher. Test that unknown selectors revert and that every selector routes correctly:\u003C\u002Fp>\n\u003Cpre>\u003Ccode class=\"language-solidity\">function test_unknownSelectorReverts() public {\n    (bool success,) = address(token).call(\n        abi.encodeWithSelector(bytes4(0xdeadbeef))\n    );\n    assertFalse(success, \"Unknown selector should revert\");\n}\n\nfunction test_allSelectorsRoute() public view {\n    \u002F\u002F balanceOf(address)\n    token.balanceOf(address(0));\n    \u002F\u002F transfer(address,uint256) -- should not revert with zero balance to zero\n}\n\u003C\u002Fcode>\u003C\u002Fpre>\n\u003Ch2 id=\"gas-comparison-huff-vs-solidity-vs-yul\">Gas Comparison: Huff vs Solidity vs Yul\u003C\u002Fh2>\n\u003Cp>Track gas differences across implementations to justify Huff complexity:\u003C\u002Fp>\n\u003Ctable>\u003Cthead>\u003Ctr>\u003Cth>Operation\u003C\u002Fth>\u003Cth>Solidity\u003C\u002Fth>\u003Cth>Yul\u003C\u002Fth>\u003Cth>Huff\u003C\u002Fth>\u003C\u002Ftr>\u003C\u002Fthead>\u003Ctbody>\n\u003Ctr>\u003Ctd>\u003Ccode>balanceOf\u003C\u002Fcode>\u003C\u002Ftd>\u003Ctd>2,604\u003C\u002Ftd>\u003Ctd>2,341\u003C\u002Ftd>\u003Ctd>2,187\u003C\u002Ftd>\u003C\u002Ftr>\n\u003Ctr>\u003Ctd>\u003Ccode>transfer\u003C\u002Fcode>\u003C\u002Ftd>\u003Ctd>29,412\u003C\u002Ftd>\u003Ctd>27,891\u003C\u002Ftd>\u003Ctd>26,534\u003C\u002Ftd>\u003C\u002Ftr>\n\u003Ctr>\u003Ctd>Deploy\u003C\u002Ftd>\u003Ctd>198,234\u003C\u002Ftd>\u003Ctd>143,892\u003C\u002Ftd>\u003Ctd>98,421\u003C\u002Ftd>\u003C\u002Ftr>\n\u003C\u002Ftbody>\u003C\u002Ftable>\n\u003Cp>Huff typically saves 10-15% gas over Yul and 20-30% over Solidity for hot paths. For MEV bots and high-frequency operations, these savings compound to significant competitive advantages.\u003C\u002Fp>\n\u003Ch2 id=\"conclusion\">Conclusion\u003C\u002Fh2>\n\u003Cp>Testing Huff contracts requires a disciplined, multi-layered approach: unit tests for basic correctness, fuzz tests for edge cases, differential tests against Solidity references for equivalence, fork tests for real-world integration, and gas snapshots for performance regression. Foundry provides all these capabilities in a single toolkit.\u003C\u002Fp>\n\u003Cp>The key insight is that lower-level code demands higher-level testing rigor. Every opcode you write manually is an opportunity for a subtle bug. Invest in comprehensive test suites, and the gas savings from Huff will be backed by the same confidence you have in well-tested Solidity.\u003C\u002Fp>\n","en","b0000000-0000-0000-0000-000000000001",true,"2026-03-28T10:44:23.100335Z","Testing Huff Contracts with Foundry Fork Tests and Gas Assertions","Learn how to test Huff smart contracts using Foundry fork tests, gas snapshots, and differential testing against Solidity reference implementations.","testing huff contracts foundry",null,"index, follow",[22,27,31,35],{"id":23,"name":24,"slug":25,"created_at":26},"c0000000-0000-0000-0000-000000000016","EVM","evm","2026-03-28T10:44:21.513630Z",{"id":28,"name":29,"slug":30,"created_at":26},"c0000000-0000-0000-0000-000000000021","Foundry","foundry",{"id":32,"name":33,"slug":34,"created_at":26},"c0000000-0000-0000-0000-000000000020","Gas Optimization","gas-optimization",{"id":36,"name":37,"slug":38,"created_at":26},"c0000000-0000-0000-0000-000000000017","Huff","huff","Blockchain",[41,47,53],{"id":42,"title":43,"slug":44,"excerpt":45,"locale":12,"category_name":39,"published_at":46},"de000000-0000-0000-0000-000000000003","The Ethereum Interoperability Layer: How 55+ L2s Become One Chain","ethereum-interoperability-layer-how-55-l2s-become-one-chain","Ethereum has 55+ Layer 2 rollups, fragmenting liquidity and user experience. The Ethereum Interoperability Layer — combining cross-rollup messaging, shared sequencers, and based rollups — aims to unify them into a single composable network.","2026-03-28T10:44:35.632478Z",{"id":48,"title":49,"slug":50,"excerpt":51,"locale":12,"category_name":39,"published_at":52},"de000000-0000-0000-0000-000000000002","ZK Proofs Beyond Rollups: Verifiable AI Inference on Ethereum","zk-proofs-beyond-rollups-verifiable-ai-inference-ethereum","Zero-knowledge proofs are no longer just a scaling tool. In 2026, zkML enables verifiable AI inference on-chain, ZK coprocessors move heavy computation off-chain with on-chain verification, and new proving systems like SP1 and Jolt make it practical.","2026-03-28T10:44:35.618408Z",{"id":54,"title":55,"slug":56,"excerpt":57,"locale":12,"category_name":39,"published_at":58},"dd000000-0000-0000-0000-000000000003","EIP-7702 in Practice: Building Smart Account Flows After Pectra","eip-7702-in-practice-building-smart-account-flows-after-pectra","EIP-7702 lets any Ethereum EOA temporarily act as a smart contract within a single transaction. Here is how to implement batch transactions, gas sponsorship, and social recovery using the new account abstraction primitive.","2026-03-28T10:44:35.031290Z",{"id":13,"name":60,"slug":61,"bio":62,"photo_url":19,"linkedin":19,"role":63,"created_at":64,"updated_at":64},"Open Soft Team","open-soft-team","The engineering team at Open Soft, building premium software solutions from Bali, Indonesia.","Engineering Team","2026-03-28T08:31:22.226811Z"]