dappcon-workshop-dapp/instructions/5 Coding: tests.md

Contract tests

Now that we have our contract written, we can use the code generation provided by EmbarkJS to write our contract unit test cases for TDD development.

Create account transaction should be successful

Our first test is to ensure that our createAccount transaction is sent successfully.

// do the create account tx
const createAccountTx = await createAccount(username, description).send();

Should create user

After our successful createAccount transaction, this should have created a user.

// Get user details from contract
const user = await users(web3.utils.keccak256(username)).call();

Should create owner for default account

The createAccount function should have also created an entry in the owners mapping with our defaultAccount

// read from the owners mapping the value associated with the defaultAccount
const usernameHash = await owners(web3.eth.defaultAccount).call();

User exists should be true

We can use our userExists function to check if a usernameHash exists. This will later be used for validation

// Check the usernamehash exists
const exists = await userExists(usernameHash).call();

Edit Account should update user details

After a call editAccount, our user's details should be updated.

1. Call edit account

   await editAccount(usernameHash, updatedDescription, updatedImageHash).send();
   

2. Then fetch the user details with the usernamehash

   const updatedUserDetails = await users(usernameHash).call();
   

Tweet event should fire when there is a tweet

We need to ensure that our contract events subscription works correctly when someone creates a new tweet via the tweet function.

1. Subscribe to the NewTweet event

   DTwitter.events.NewTweet({
       filter: { _from: usernameHash },
       fromBlock: 1
   })
   .on('data', (event) => {
       assert.equal(event.returnValues.tweet, tweetContent);
   });
   

2. Do the tweet

   await tweet(tweetContent).send();
   

Run tests

Let's run the tests to ensure they are all passing. In a new terminal, run:

embark test

Test results

Your test results should appear similar to the following:

DTwitter contract
    ✓ transaction to create a dtwitter user 'testhandle' with description 'test description' should be successful (114ms)
    ✓ should have created a user 'testhandle' (60ms)
    ✓ should have created an owner for our defaultAccount
    ✓ should know 'testhandle' exists (49ms)
    ✓ should be able to edit 'testhandle' user details (186ms)
    ✓ should be able to add a tweet as 'testhandle' and receive it via contract event (54ms)

Note: there is a known error with ganache that sometimes causes last test does to fail with the error ERROR: The returned value is not a convertible string. We are currently investigating this issue.