Today is our first day using Node, so we will practice doing some basic operations. Ready to start?

• Fork this repo
• Clone this repo

• Upon completion, run the following commands:

  git add .
  git commit -m "Solved lab"
  git push origin master

• Create Pull Request so your TAs can check up your work.

This exercise will be completed through a series of tests. You should be familiar with testing from previous lessons and exercises, but just in case, here is a short recap of Intro to testing. 😉

Software testing is a process of executing an application to validate and verify that it meets the business and technical requirements and works as expected.

Testing is a process, not a single activity. The earlier we start developing and conducting tests, the better we'll be at preventing mistakes in the code or product design.

In this exercise you're given all of the tests that you'll need to arrive at a solution. All you need to do is execute them and confirm that your code meets all of the requirements.

Tests prove that your code actually works in every situation in which it’s designed to work. Even when you are improving the design or creating new features, you can change your current code without breaking what already works.

Mocha is a feature-rich JavaScript testing framework running on Node.js and in the browser, making asynchronous testing simple and fun.

We have already included Mocha in the project you just forked, so let's see how to use it to implement our code.

To start using mocha, you have to install it as a dependency for this project. Remember that we should always use the Node Package Manager (npm) to manage all the packages in our projects.

To install mocha, run the following command:

$ npm install mocha

If you have successfully installed mocha, you should see a node_modules folder in your project directory. This means that the package was installed locally. If you open the file package.json, it should include a property named dependencies, under which you'll see mocha and the corresponding package version.

Before we start coding, let's explain the provided project structure:

test/
├── index.spec.js
package.json
index.js

We are going to be working with the index.js file. Here we will write the implementation of our SortedList class.

The test folder contains all the tests we will execute with Mocha.

Running our tests with Mocha is super easy; you just have to run npm test.

$ npm test

> mocha

  SortedList
    Constructor
      1) should have items and length properties
    #add(x)
      2) should add a single value to SortedList
      3) should add a third value to SortedList
      4) should add a value while keeping the list sorted
    #load(i)
      5) should return an OutOfBounds exception if there is no element in that position
      6) should return the element in that position
    #max()
      7) should return an EmptySortedList exception if there are no elements in the list
      8) should return the max (highest) value in the list
    #min()
      9) should return an EmptySortedList exception if there is no elements in the list
      10) should return the min (lowest) value in the list
    #sum()
      11) should return the sum of all elements in the list
      12) should return 0 for an empty sorted list
    #avg()
      13) should return an EmptySortedList exception if there are no elements
      14) should return the average of elements in the list

  0 passing (13ms)
  14 failing

Don't worry that none of the tests are passing... you will make them ALL PASS!! 😄

The task here is to create a class that maintains a sorted list of numbers in ascending order.

Go in the index.js file and there you will find the bare bones of the SortedList class.

The SortedList class will have the following methods:

new SortedList should create a new object from the SortedList class.

The object should have two properties: items and length.

• items should be an array,
• length should be the number of elements in the array.

The add(item) method should add the value item to the items array, while ensuring that the items in the array stay sorted in ascending order.

What does this mean? Well, if an array of items has these elements: [2, 5, 7], and if 6 is added, the array of items should be as follows: [2, 5, 6, 7].

You might want to update the length property that returns the length of the list.

The load(position) method will get the value at index position in the list.

Example: if an instance of SortedList has elements: [2, 5, 7], when load(2) gets called it should return 7, since this is element at that position in the array. Check the tests to see more examples.

In addition, make sure you throw an error with the message "OutOfBounds" if a user tries to get an element in a non-existing position (e.g. if the array has 5 elements and we are trying to get the element at position 7).

To throw an error, you can do the following:

throw new Error('OutOfBounds');

The max() method should return the highest value of the array.

In case you have an empty SortedList, you must throw an error with the message "EmptySortedList". For this, you can use:

throw new Error('EmptySortedList');

The min() method should return the lowest value of the array.

In case you have an empty SortedList, you must throw an error with the message "EmptySortedList".

The sum() method should return the total sum of every value in the array.

At this point, we will not tell you anything else. Just go ahead and check the corresponding test and see if anything else needs to be added. You can do this! ❤️

The avg() method should return the average value of the array.

Just as before, check the corresponding test to see if there's anything else that needs to be added.

And you have reached the end!

Happy Coding! ❤️