ABI to Mock

Given an ABI file generate a mock contract with functions that allow setting the return value of all view functions.

The simplest form of mocking that generates contracts that can be easily integrated into a fuzz testing suite.

Works well with the Recon Extension (coming soon) and the ABI to Invariants Builder.

Features

Generates fully functional Solidity mock contracts
Supports complex data types including structs and nested arrays
Maintains function signatures and event definitions
Customizable contract names and output locations
Available as both a CLI tool and JavaScript library

Generated Mock Features

Complete function signatures matching the original contract
Setter functions for return values
Complex type support (structs, arrays, mappings)

Installation

npm install abi-to-mock

Usage

Command Line Interface

npx abi-to-mock <abi-file> [options]

Options:
  --out, -o   Output directory (default: "./out")
  --name, -n  Contract name (default: "Contract")

Example:

npx abi-to-mock ./MyContract.json --out ./mocks --name MyContract

Using with Foundry

forge build

npx abi-to-mock out/ERC20Mock.sol/ERC20Mock.json --name Erc20Mock --out src/

Programmatic Usage

// Node.js
const AbiToMock = require('abi-to-mock');
// or ES Modules
import AbiToMock from 'abi-to-mock';

// From file
AbiToMock('./MyContract.json', './mocks', 'MyContract');

// From ABI object
const abi = [
  {
    "inputs": [],
    "name": "getValue",
    "outputs": [{"type": "uint256"}],
    "type": "function"
  }
];
AbiToMock.generateMock(abi, './mocks', 'MyContract');

// Browser usage
import { generateMockString } from 'abi-to-mock';
const mockCode = generateMockString(abi, 'MyContract');

API Reference

// Node.js API
AbiToMock(abiPath: string, outputDir?: string, name?: string): MockContract
AbiToMock.generateMock(abi: ABI[], outputDir: string, name: string): MockContract

// Browser API
generateMockString(abi: ABI[], name: string): string

Recon Docs