## 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.