App QA

Unit vs Functional Testing | Key Differences, Pros, Cons

Read this post to learn the unit vs functional testing comparison. Here we breakdown the benefits and problems they come with.

What is Unit testing?

Known as "unit" or "unit-level" testing, because it focuses on individual components in your application's code. In other words, unit tests test the smallest possible piece of code—usually a method or function—and ensure that it behaves as expected when executed by your application.

Unit tests are written in a language called Swift or Objective-C, which is different from JavaScript because it doesn't have any global variables. This makes it easier for unit tests because there are no global variables for your code to access outside of its scope.

Unit testing is a good way to test your code and find bugs in it, but if you're writing unit tests for every function or method, then you're doing it wrong. You should focus on writing tests that cover specific parts of your application. If there are any parts where this isn't possible (for example, if an API call needs to be made from multiple places), then write those separate sets of tests instead.

Functional Testing

As the name suggests, it's a way to test the functionality of an app without testing the code, which is why it's often used in conjunction with unit testing. Functional testers are responsible for verifying that all parts of an application work together as expected and don't produce unexpected results when they're tested together. This includes verifying that every menu item works as expected when selected or clicked on, as well as checking all input fields are filled out correctly when entering information into them (and ensuring user errors do not occur).

Functional testing is a type of software testing where you test your application in isolation. In this type of testing, you're trying to ensure that each part of your application works as expected and performs its job correctly. This includes things like making sure users can log into their accounts, find the right information on their pages, and interact with features like ads or forms. WeTest provides the industry’s leading APP Functional Testing test specialists, covering all function points, including specific business processes and industry-specific standards. Moreover, game developers can opt for WeTest Mobile Game Functional Testing which is backed by a professional team with experience working with leading names like Supercell, Riot Games, and more. 

Unit vs Functional Testing

A key difference between a unit and functional test is that when you run a unit test on your code (or run any other kind of automated script), it will return either true or false depending on whether or not there was any problem with how things were supposed to go down when tested - whereas with functional tests – which are more comprehensive – they will always return true because they're designed around finding problems rather than confirming whether something works properly.

This makes them significantly more reliable than their component-based counterparts: no matter what happens during runtime while running through these processes (like crashes), they'll always tell us exactly which areas need improvement before moving on to another round next time around.

You can't use functional testing for security or performance testing.

Functional tests are written to test the functionality of your application, not its security or performance. Functional testing can be faster than unit testing because it uses an automated tool to complete most of the work for you. However, since this approach doesn't require any human intervention, it's more likely to produce false negatives than true positives—that is, if your code contains bugs but they're not caught by functional tests (for example), then other types of tests would need to be run before those issues could be fixed properly.

Unit tests are usually much faster, but Functional tests can be more reliable.

The most important difference is that unit tests are usually much faster, but functional tests can be more reliable. Functional tests are also more thorough because they test all of your code in one go. Functional testing is often done on a machine that isn't being used for development—for example, if you have a laptop at home with no other projects running on it while you're working on yours, then it makes sense to run your functional tests there instead of waiting until you get home again.

This means they can be run while other projects are ongoing or at any time during the day (you don't need anyone else's permission). Functional testing can also parallelize; this means there will be multiple workers running different parts of each test case simultaneously so that everything runs quickly without slowing down too much due to waiting around for each step in the process.

Functional and unit testing complement each other.

There are times when you want to write a unit test. You might be writing an application that's small and simple, or it could be a large piece of software that has been written by several people with different skill levels and experience. Regardless of the reason for testing, there are times when you need to make sure that your code is doing what it should be doing.

Unit testing is when you're testing your application in combination with other units.

Unit tests are fast and easy to write, as they only test one unit at a time. They can also be run in parallel, which means that if you have multiple units that need to be tested together (for example, an app and its database), then all of these tests can run simultaneously on different machines or even across multiple servers.


To conclude unit vs functional testing, we can state that unit testing and functional testing both play a vital role in testing your code. Unit testing is a form of software testing that focuses on individual units of code. It helps you to test the functionality of your application and make sure that each element works as it should. Functional testing, on the other hand, is used to check whether or not an entire system works properly by running through its various components in sequence.

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