Unit Testing JavaScript Applications

Unit Testing JavaScript Applications

What is unit testing?


Unit testing isn’t a replacement concept within the software development world.  Because of Kent Beck, the concept of unit testing was introduced in Smalltalk, and then the concept was transferred to several other programming languages, such as C, C++, and Java. The classical definition of unit testing is that it’s a bit of code (usually a method) that invokes another piece of code and later checks the correctness of some assumptions. The definition is technically correct; however, it doesn’t show us the way to make a very good unit test.  So as to write down an honest unit test, we’d like to know the wants of an honest unit test.


 A good unit test should be;

·         Automated,

·         Repeatable,

·         Easy to know,

·         Incremental,

·         Easy to run,

·         And fast.

A good unit test should be automated and repeatable, which suggests that other team members can repeat running the appliance unit tests for each significant code change automatically. It should even be easy to know in order that other team members can understand what your test means and may continue adding more test suits or updating an existing test case. An honest unit test should be incremental;  this suggests that the unit test should be updated if a replacement relevant defect is detected within the code,  which suggests that this defect won’t happen again as long as this unit test is running periodically. Finally,  an honest unit test should be easy to run; it should travel by executing a command or by clicking a button and will not take an extended time for execution because fast unit tests can help in increasing the event team’s productivity.

So let’s return to the definition and refine it. Unit testing maybe a piece of code that invokes another piece of code and checks the correctness of some assumptions later. Unit testing should be automated, repeatable, easy to know, incremental, easy to run, and fast.

Unit Testing JavaScript Applications

Importance of unit testing


Unit testing applications aren’t something nice to possess.  It’s actually a compulsory activity for having successful software solutions which will deal with different changes across time with high stability.  There’s no excuse to skip unit testing of applications even for projects with a decent schedule. The importance of unit testing might not appear within the early stages of the project; however, its rewards are visible within the middle and therefore the final stages of the project, when the code becomes difficult, more features are required and more regression defects appear

Without unit testing, the mixing of the various components within the system becomes complicated. This complexity results from the tracing of the defects of not only the mixing between the components but also each “buggy” component. This complicates the lifetime of the developers by making them spend nights within the office so as to satisfy the schedule.

The number of latent defects and therefore the regression defects becomes unmanageable when the code base becomes complicated and unit testing isn’t available. The developer may decide on a carefully chosen defect. This defect can happen again because there’s no repeatable test suit to make sure that the defect won’t happen again after a group of code changes.

Having more defects per line of code affects the application’s quality badly, and this suggests that long has got to be spent on testing the appliance. Bad quality applications have an extended test cycle for every project deployment because they need a high probability of getting more defects for each code change, which results in more pressure on the project management, the project developers,  and therefore the project testers.

Having good unit testing is often an honest reference for the system documentation because it contains the test scenarios of the system use cases.  Additionally to the present, unit testing shows how the system APIs are used, which reflects the present design of the system.  This suggests that unit testing may be a powerful basis of code and style refactoring for having more enhancements within the system. Having good unit testing minimizes the number of regression defects because in good unit testing the system features a repeatable number of test cases for each relevant defect.

Having endless integration job that runs periodically on the appliance unit tests will make sure that these defects won’t happen again, because if a selected defect appears again thanks to a change within the application code, then the developer is going to be notified to repair the defect and make sure that the test suit of this defect passes successfully.

As a result of reducing the regression defects, having good unit testing reduces the test cycle for every phase (or system deployment). Additionally to the present, the appliance can have more and more features per iterations or phase peacefully without fear if these features shall break an existing module that has a good unit test.


Mansoor Ahmed is Chemical Engineer, web developer, a writer currently living in Pakistan. My interests range from technology to web development. I am also interested in programming, writing, and reading.
Posts created 421

Related Posts

Begin typing your search term above and press enter to search. Press ESC to cancel.

Back To Top