function etch(address who, bytes calldata code) external;Sets the bytecode of an address who to code.
bytes memory code = address(awesomeContract).code;
address targetAddr = makeAddr("target");
vm.etch(targetAddr, code);
log_bytes(address(targetAddr).code); // 0x6080604052348015610010...Some chains, like Blast or Arbitrum, run with custom precompiles. Foundry is operating on vanilla EVM and is not aware of those. If you are encountering reverts due to not available precompile, you can use vm.etch cheatcode to inject mock of the missing precompile to the address it is expected to appear at.
{{#include ../../projects/cheatcodes/test/BlastMock.t.sol:all}}Injecting mocks of precompiles might be tricky as such mocks will not fully emulate the actual precompile behavior on-chain.
Mock in the case above will not cause the actual yield to be accrued if any yield mode is configured.
Forge Standard Library