Solidity-Testing

1. Solidity Testing - Best Practices, Methodologies and errors
2. This is a space reserved to collect,maintain and share best-practices of solidity smart contract Testing

Test Practices:

Test Coverage:

https://medium.com/edgefund/testing-and-code-coverage-of-solidity-smart-contracts-660cb6291701

Issues and Fixes:

Issue-1:

While testing solidity smart-contracts using truffle, tests fails.

• Issue Description:
ReferenceError: regeneratorRuntime is not defined
• Context: Testing a DNS-Smart contract @ https://github.com/kanthgithub/DNSDapp/blob/master/contracts/DNSDappMaster.sol

Sample Test:

const DNSDappMaster = artifacts.require('DNSDappMaster')

contract('tests DNSDapp functions of DNSDappMaster contract', async () => {
  it('should be deployed to the test chain', deployToTestChain)
  it('assert that non-existent name check returns false', testNonExistentDNSName)
})

async function deployToTestChain () {

  const dNSDappMaster = await DNSDappMaster.deployed()

  assert.isNotNull(dNSDappMaster)
}

async function testNonExistentDNSName () {

  const dNSDappMaster = await DNSDappMaster.deployed()

  assert.isNotNull(dNSDappMaster)

  const fakeDNSName = 'alien'

  const actual = await dNSDappMaster.isAValidDNSNameString(fakeDNSName)

  assert.isFalse(actual)
}

Solution:

babel/babel#5085

https://stackoverflow.com/questions/33527653/babel-6-regeneratorruntime-is-not-defined/36821986#36821986

In my case installing babel-plugin-transform-runtime solved my issues:

npm install --save-dev babel-plugin-transform-runtime

Then, in .babelrc

{
  "plugins": [
    ["transform-runtime", {
      "polyfill": false,
      "regenerator": true
    }]
  ]
}

Credits To: https://github.com/iraklisg

---

Events in Solidity Tests:

• Event emitted only in some cases in tests
• How to listen for contract events in JavaScript tests?

I've discovered that not all events are displayed in the truffle output window, although they might have fired correctly with the execution of a contract. I believe this to still be an issue

After spending hours on this today I have come up with a solution to test that specific events are fired.

Here's my example truffle javascript test:

it("should do something that fires SaleMade", function() {
    return myContract
        .stockShelf("beer", "wine", {from: sellerAccount})
        .then(() => myContract.sell("water", "bread", {from: sellerAccount}))
        .then(() => utils.assertEvent(myContract, { event: "SaleMade", logIndex: 1, args: { name: "bread" }}));
}
The above filters the fired events that match the filter object passed to the assertEvent utility function I have in utils.js in the same folder. At the top of my javascript test I have declared:

var utils = require("./utils.js");
A snippet of my utils.js class is as follows:

var _ = require("lodash");
var Promise = require("bluebird");

module.exports = {
    assertEvent: function(contract, filter) {
        return new Promise((resolve, reject) => {
            var event = contract[filter.event]();
            event.watch();
            event.get((error, logs) => {
                var log = _.filter(logs, filter);
                if (log) {
                    resolve(log);
                } else {
                    throw Error("Failed to find filtered event for " + filter.event);
                }
            });
            event.stopWatching();
        });
    }
}
This requires other npm packages that aren't included with truffle by default. By default truffle doesn't include npm packages. I setup npm and installed the required packages like this:

npm init
npm install bluebird --save
npm install lodash --save
EDIT: Using testrpc

Discussion and workaround:

• https://ethereum.stackexchange.com/questions/15353/how-to-listen-for-contract-events-in-javascript-tests/21661#21661
• trufflesuite/truffle#136

Credits: https://ethereum.stackexchange.com/users/7132/mkaj

---

Read public variables in tests

Discussion and workaround:

https://stackoverflow.com/questions/55947716/how-to-read-public-variable-in-solidity-with-truffle-test-codes