solidity-test-utils v1.1.0

Solidity-test-utils

Set of testing utilities

Install module

  npm i solidity-test-utils

Import module

  const u = require('solidity-test-utils')

Content

• u.balance.assertChange
• u.shouldFail
• u.time.forward from this https://medium.com/edgefund/time-travelling-truffle-tests-f581c1964687

Details

u.balance.assertChange

Asserts that balance has changed after function call.

Step 1 - register your contarcts

Register abi and address for token contract with u.balance.register. You only need to do this once per contract.

Should be a nicer way of getting ABIs of truffle deployed contracts.

contract("Crowdsale", async accounts => {

  before( async () => {
    ...
    tokenA = await TokenA.deployed()
    u.balance.register(tokenA)
    ...
  })

  ...

Step 2 - test your function

Here is an example that test function crtowdsale.buyTokens. This code will ensure that after execution:

1) accounts[2] will increare balance of tokenA by amt tokens; 2) wallet accounts[2] will pay totalWeiPaid wei 3) wallet accounts[1] will receive totalWeiPaid wei from the (2)

  it('Can purchase tokens', async () => {
    var totalWeiPaid = 999
    var amt = 111

    await u.balance.assertChange(
      async () => {
        await crowdsale.buyTokens({
          from: accounts[2],
          value: totalWeiPaid
        })
      }, {
        [tokenA.address]: { accounts[2] : amt },
        'eth': {
          accounts[1] : totalWeiPaid,
          accounts[2] : -totalWeiPaid
        }
      }
    )
  })

Tx Commission

Is calculated and accounted automatically inside

Why square brackets in [tokenA.address]?

To get value of tokenA.address and use it as object key

Why positive and negative numbers?

Positives are for balance increase and negatives are for deductions.

How to check for ether balance?

Use 'eth' instead of token address

My token have non-standard way of getting balance?

Check this code, should be easy to extend.

u.shouldFail(f)

Asserts that executing async function f will result in tx revert.

await u.shouldFail(
  async () => crowdsale.doSomethingThatIsNotPossible()
)

u.time.forward

Nice way to test time-dependent logic in truffle and ganache Code is from https://medium.com/edgefund/time-travelling-truffle-tests-f581c1964687

await u.time.travel(freezeTime)