Set Sail - Walkthrough

Steps

• Discuss with your classmates how the domain model for Ship might be added to with the above user story.
• Create a new test spec for the user story.
• Write the code that makes this test pass.
• Add, commit with a meaningful message, and push to GitHub.

Domain Model

From the user story:

As a cruise ship captain,
So I can get passengers started on their journey,
I want a ship to be able to set sail from a port.

The domain model for Ship now might look like this:

A setSail method has been assumed from the doing words set sail in the user story.

it can set sail

Now we need to write the test for our new setSail method. In order to be able to test the method works, the state of our Ship object is going to have to change. The state in question is the startingPort property.

Lets see how a test might look:

Here we have an example of a Four-Phase Test:

• setup const ship = new Ship('Dover');
• exercise ship.setSail();
• verify expect(ship.startingPort).toBeFalsy();
• teardown - Jest handles teardown for us automatically

We've used a new Jest matcher here: toBeFalsy. This does exactly what it says on the tin - expects the return value to be falsy.

Run your test. It should fail with :red_circle: TypeError: ship.setSail is not a function.

Write the code that makes the test pass

:exclamation: You should be able to do this without the walkthrough. Once you've passed the test, then proceed.

Add, commit with a meaningful message, and push to GitHub

Look at the last walkthrough for an example of a meaningful commit message.