Gain insights into testing functions and classes, mocking dependencies, naming tests, testing asynchronous code, Node.js code, and browser API-dependent code using Jasmine in your JavaScript app.

Using Jasmine to Unit Test Your JavaScript App.png

dockerfile.v6.tar.gz

Run jasmine

live Jasmine

Live jasmine in unit-testing-course folder

Run jasmine flat

Run jasmine --config=./jasmine.json

Once jasmine

Run jasmine-browser-runner console

Run jasmine-browser-runner console-copy

Run jasmine-browser-runner serve

Run jasmine-browser-runner serve 3000

This course will teach learners how to test functions and classes, mock dependencies, name the tests, test asynchronous code, test Node.js code, and test browser API-dependent code.

Using Jasmine to Unit Test Your JavaScript App

When our applications have instances of `Date`, we need to be able to test that interaction. One such way is using `jasmine.clock`.
Let’s see an example of a function using `Date` to calculate how many days ago a date was.

# The `Date`-dependent function

Looking at the `daysAgo` function logic in `src/days-ago.mjs` line by line, we see the following:

- ```js
  const nowMilliseconds = Date.now();
  ```

  It starts with the current date in milliseconds. That’s how many milliseconds have elapsed since January 1, 1970 UTC.

- ```js
  const dateMilliseconds = date.valueOf();
  ```

  This line takes the passed-in date value in milliseconds so that they’re both in comparable units: milliseconds.

- ```js
  const agoMilliseconds = nowMilliseconds - dateMilliseconds;
  ```

  This line subtracts `date` from `now` and gets the difference in milliseconds.

- ```js
  const millisecondsInADay = 1000 * 60 * 60 * 24;
  ```

  This line calculates how many milliseconds in a day. There are 1,000 milliseconds in a second, 60 seconds in a minute, 60 minutes in an hour, and 24 hours in a day.

- ```js
  const daysAgo = agoMilliseconds / millisecondsInADay;
  ```

  This line divides the milliseconds ago with the milliseconds in a day, getting how many days ago the date was.

- ```js
  return Math.round(daysAgo);
  ```

  This line rounds the `daysAgo` number to the nearest integer because we want to get `This date was 7 days ago` and not `This date was 7.1430499282 days ago`.

# Testing the Date-dependent function

Let's run that using the code playground below and break the test down after.

Learn testing functions that depend on the date and time directly, in the browser and Node.js context.

Overview

Testing JavaScript with Jasmine

Testing Asynchronous Code

Debugging Jasmine Tests

Summary

How to Test Functions Depending on Date

The `Date`-dependent function

How to Test Functions Depending on Date

The Date-dependent function

The `Date`-dependent function