testGen.js

#!/usr/bin/env node

/**
 * Audits.dev - Truffle Test Generator
 */

const fs = require('fs')

const getConstructor = (contract) => {
  for (let i = 0; i < contract.abi.length; i++) {
    if(contract.abi[i].type == 'constructor') {
      return contract.abi[i]
    }
  }
}

const genConstructorParams = (constructor) => {
  let lines = []
  if(constructor != undefined) {
    for (let i = 0; i < constructor.inputs.length; i++) {
      lines.push(constructor.inputs[i].name)
    }
  }
  return lines
}

const genConstructorLine = (constructor) => {
  let line = ''
  if(constructor != undefined) {
    for (let i = 0; i < constructor.inputs.length; i++) {
      line += constructor.inputs[i].name + ', '
    }
  }
  line += '{from: maintainer}'
  return line
}

const genTestContent = (contract, constructorParams, constructorLine) => {
  let testContent = `
/**
 * This file was created by truffle-test-generator.
 * For every test, a new contract will be created in the
 * top beforeEach block. This line uses the arguments for
 * your contract's constructor with the same variable names.
 * Each public, non-constant (view) method has a describe
 * block generated for it.
 */
const ${contract.contractName} = artifacts.require('${contract.contractName}')

contract('${contract.contractName}', (accounts) => {
  const maintainer = accounts[0]
  const user1 = accounts[1]
  const user2 = accounts[2]
  const stranger = accounts[3]

  let ${contract.contractName.toLowerCase()}`

  if(constructorParams.length > 0) {
    testContent += `

  // Be sure to update these constructor values`
    for (let i = 0; i < constructorParams.length; i++) {
      testContent += `
  let ${constructorParams[i]} = 0`
    }
  }

  testContent += `

  beforeEach(async () => {
    ${contract.contractName.toLowerCase()} = await ${contract.contractName}.new(${constructorLine})
  })
`

  for (let i = 0; i < contract.abi.length; i++) {
    if(contract.abi[i].type == 'function') {
      testContent += `
  describe('${contract.abi[i].name}', () => {

  })
`
    }
  }

  testContent +=
`})
`
  return testContent
}

const cwd = process.cwd()
const jsonFile = cwd + `/build/contracts/${process.argv[2]}.json`
let testFile = cwd + `/test/${process.argv[2]}_test.js`
let contract

try {
  contract = JSON.parse(fs.readFileSync(jsonFile, 'utf8'))
} catch (err) {
  console.error('Please provide a contract name and be in the top-level directory of your Truffle project\n', err)
  return err
}

const constructor = getConstructor(contract)
const constructorParams = genConstructorParams(constructor)
const constructorLine = genConstructorLine(constructor)
const testContent = genTestContent(contract, constructorParams, constructorLine)

if(fs.existsSync(testFile)) {
  testFile = testFile.replace('.js', '-new.js')
}

fs.writeFile(testFile, testContent, (error) => {
  if(error) return console.error(error)
})

console.log('Wrote to:', testFile)