TDD Feature-Level Tests
Feature Test I

Feature tests exercise behavior by simulating a user navigating the application in a web browser.

Imagine we wanted to create a simple web-based poetry writing application.

The first feature test we want to write is to check our application’s empty state. The functionality we want to test is:

  • When a user visits the homepage, the poems section is empty

We want to make sure that when there are no poems in the database, there are no poems rendered on the homepage. This is the application’s empty state.

The testing suite for our poetry app would begin with nested describe blocks like this:

describe('Poetry web app', () => { describe('user visits root', () => { }); });

The term ‘root’, refers to our application’s entry point, which in this example is the home page that users will visit in their browser.

Next, we add an it block to describe the behavior we want to test in our app:

describe('Poetry web app', () => { describe('user visits root', () => { it('page starts blank', () => { }); }); });

When a user visits the root of our app, they should have a blank page on which to write their own poem.

The Plumbing

Next, we reach for our feature testing toolbelt. We start by to using the global browser variable that is provided by WebdriverI/O.

The browser variable is powerful because it gives us access to the browser that Phantom is running in the background. We can simulate a user interacting with our website by calling different methods on the global browser variable in our test suite.

For example, we can use browser.url() to simulate a user visiting the home page of our application, which is the first behavior we want to test.

The .url method navigates to the URL that is passed to it as an argument. The following line of code would navigate to the Codecademy website in the Phantom browser.


In the case of our poetry web app, we will pass in '/' as the argument, which will point the browser to the root file of our project, which in this case is our index.html.

The code would look like this:

describe('poetry web app', () => { describe('user visits root', () => { it('page starts blank', () => { browser.url('/'); }); }); });



Imagine you are a developer working on a project that includes creating a web application with a message feature.

The first feature you want to test in your web app is that no messages appear on the page when a user visits the project root.

  • Inside the describe blocks in user-visits-root-test.js file, write an it block with the string: starts blank, and an empty callback function.

Inside the it block, call the .url() method on the global browser variable and pass '/' as the argument.

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