Unit testing for NodeJs Applications

As you add features to your application, you can run the risk of introducing bugs and the application is incomplete. If it’s not tested, and manual testing is tedious and prone to human error. Automated testing has become increasingly popular with developers automated testing involves writing logic to test your code rather than running. True application functionality by hand.

If the idea of automated testing is new to you, think of it, like a robot, doing all of the boring stuff for you, allowing you to focus on the interesting stuff. Every time you make a change to your code, you can get the robot to make sure backs haven’t Crypt in although you may not have completed or started your first node application yet it’s good to get a handle on how you Implement automated testing because you will be able to write tests. As you develop in this chapter, we will look at two types of automated testing, unit, testing, and acceptance, testing. Any testing tests code logic directly typically at a function or method level and its application to all types of applications. Unit testing, the methodology can be divided into two major forms test-driven development or TDD. End.

Behavior-driven development or BDD practically speaking BDD and TDD are largely the same thing. With the difference mostly being in the language, used to describe the tests as you will see when we go through some examples. There are other differences between TDD and BDD. But They are beyond the scope. Acceptance testing is an additional layer of testing most commonly used for web application acceptance. Testing involves scripting control of a browser and attempting to trigger web application functionality with it.

We will look at established solutions for both unit and acceptance. Testing for unit testing, we will cover the Node’s assert module and the mocha node unit vows and should dot J’s Frameworks for acceptance, testing. We will look at Toby And soda Frameworks.

Unit testing

Unit testing is a type of automated testing where you write logic, to test discrete parts of your application. Writing tests, makes you think more critically about your application design choices and helps you avoid pitfalls early. The tests also give you confidence that your recent changes haven’t introduced errors. Although unit tests take a bit of work upfront to write, they can save you time by listening to the need to manually retest every time you make a change to your application, you need testing can be tricky and asynchronous. Logic can add new challenges as synchronous unit testing can run in parallel. So you have got to be careful to ensure that Don’t interfere with each other. For example, if you are test creating temporary files on this, you will have to be careful to delete those files after a test. You don’t delete the working file of another test that hasn’t finished. For this reason, many units, testing Frameworks include flow control, sequence, the running tests. In this section, we will show. How do you follow

Nodes built-in assert module a good building block for TD style, automated testing Node unit a long time, favorite TD style testing framework of the node community. Moshe, a relatively new testing framework that can be used for TDD or be distant testing. Voz a widely used BDD-style testing framework. Shoot the Jays a module that builds on nodes. Assert module to provide BDD style testing.

The assert module

The basis for node most node unit, testing is the built-in assert module, which tests set conditions. And if the condition isn’t met throws, an error node as at module is taken advantage of by many third-party testing Frameworks, but even without a testing framework, you can do user testing with it.

A simple example

Suppose you have a simple Node application that stores items in memory and asserts it to do that. What you think it’s doing in the following listing? Defines a module containing the code application functionality, module logic supports creating retrieving intelligent witty items. It also includes the simple do async method to look at testing asynchronous methods to see the file todo.js.


Using a unit testing framework simplifies unit testing Frameworks generally keep track of how many tests have been done and they make it easy to run multiple test scripts, a member of excellent resting Frameworks has been created by node Community. We will start with a look at the snowed unit as it’s a time-tested favorite of no developers who prefer TDD flavor testing. Note unit provides a command-line tool that will run all of your application tests and let you know how many paths and failed. Saving you from having to implement your own application-specific testing. In this topic, we will learn how to write tests with node units that can test both node application code and client-side code. Run using a web browser, you will also learn how node unit deals with the challenge of keeping track of running tests synchronously. Installing note, unit. To install the node unit, run the following command.

npm install node unit

Once it has been completed, you will have a new command available named node unit. This command is given one or more directories or files containing tests as an argument and it will run all scripts with the extension dot J’s within the director is passed.

Testing note applications with node unit. To add node unit, tests to your project, create a directory, for them, each test script should populate the exports object with the tests. Here is an example node unit server-side test file.

Note that the previous test script doesn’t require any modules note unit, automatically, including nodes, assert modules method in an object that it passes to each function exported by a test script. In the preceding example, this object is called a test. Once each function exported by the test script, has been completed the done method should be called. It isn’t called the test will report, a failure of undone tests by requiring that this method be called node unit checks that all tests that were started were also finished. It also can be helpful to check that all the assertions files within a test. Why wouldn’t assertions fire? When writing in it tests, the danger always exists that the test logic itself is buggy leading to false positives. Logic is the test may be written in such a way that certain assertions don’t evaluate. The following example shows how to test dot done can fire and Report success, even though one of the assertions, as an executed,

If you want to safeguard against this, you could manually Implement an assertion counter such as the one shown in the following using.

This is tedious. Note unit offers a nice way to do this by using test dot expect. This method allows you to specify the number of assertions each test should include the result is fewer lines of unnecessary code. In addition to testing node modules node. The unit also allows you to test client-side, JavaScript, giving you the ability to test one test harness for yourself. Web applications can learn about that and more Advanced Techniques by checking out node, units, online, and documentation GitHub.


Mocha is the newest testing framework you will learn about in this section now and it’s an easy form of two graphs. Although it defaults to a bdd style, you can also use it in a TD Style. Maka has a wide variety of features including Global variable, leak detection. And like node, unit Maca, supports client-side, testing.

By default mocha tests are defined and their logic is set up using BDD flavored functional called describe eat before after the for each. And after each, alternatively, you can use mochas TDD interface, which replaces the use of described with sweet it with the test. With setup and after with tear down, for example, you will stick with the default BDD interface.

Global variable leak detection. If you have little need for Global variables that are readable application-wide and it’s considered a programming-based practice to minimize your use of them. But in JavaScript, it’s easy to in effort and click create Global variables by forgetting to include the where keyword when declaring a variable mocha helps detect accidental, Global variable leaks by Throwing an error when you create a global variable using during testing If you want to disable Global Leak Detection, run mocha with the – – ignored licks command-line option. Alternatively, if you want to allow a set of numbers of Global’s to be used, you can specify them using – – Global’s command-line option followed by a comma-delimited list of allowed Global variables.

Acceptance testing

Acceptance testing also called functional testing tests outcomes, not logic. After you have created a suite of units. Tests for your project acceptance testing will provide an additional level of protection against boxes that any testing might not detect. Acceptance, testing is similar, conceptually to testing by end-users, who follow a list of things to test, but being It makes acceptance testing fast and it doesn’t require human labor acceptance. Testing also deals with complications, created by client-side, JavaScript Behavior. If there is a serious problem, created by client-side JavaScript, server-side unit, testing won’t catch it, but through acceptance, testing will, for example, your application may make use of client-side JavaScript. Form, validation acceptance, testing will ensure that your validation logic Works rejecting and accepting input appropriately, or for another example, you may have a jokester even Administration functionality such as the ability to browse content to select featured content for the website front end.

That should only be available to authenticated users to deal with this. You could write a test to ensure that Jack’s request. Produces expected results. When the user logs in and writes another test to make sure that those who are not authenticated cannot access this data. In this section, you will learn how to use acceptance, testing Frameworks to And soda provides the benefits of harnessing GL browsers for acceptance testing first OB which we will look at first is easier to learn and to get up and running on.

I am also adding a few Video’s for Unit testing in Nodejs

  • Jest crash course

  • Unit testing with Mocha and Chai
Spread the love