Automation Testing

Is Automation Testing The Right QA Option For You?


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Automation Testing & Unit Testing

The process of verifying the functionality of a single unit or module of an application during the development phase of a Software Development Life Cycle is known as Unit Testing. The ideal and efficient manner to carry out unit testing is the automated way though it can be performed annually as well. To make the process easy to go with and quicker, there are many automation testing tools available for this in the industry today. 

What is Integration Testing?

Process Validation and Verification of a set of modules together (dependent modules of an application) is known as Integration testing (also known as Component Integration Testing). This type of testing is intended to test an entire component’s functionality in a system. Also, it is carried out once the unit testing is completed for an application. This type of testing is suitable for systems where hardware is embedded with software etc. 

Also, we have System Integration testing in the picture (SIT) which deals with the testing of many subsystems of an application. 

What is Functional Testing?

Functional Testing of a system is nothing but a superset of integration testing. It involves testing a group of modules and components (might be dependent or independent) together to verify the system’s functionality and ensure that the code running behind it is working properly without any exceptions on the user’s end. 

However, it is proven that for an optimized return on investment (ROI) for the business or a specific project, your application should have as many Units tests as possible, lesser integration tests, and minimal functional tests executed. 

How the Three Testing Types are Different From Each Other?

  1. The foremost and very basic difference between the three kinds is that Unit testing runs on individual units of an application, whereas functional testing involves testing the entire application’s or system’s working against the software requirement specification (SRS) document. Also, integration testing deals with the testing of integrated modules in the application. 
  2. Another difference between the stated testing types is based on the techniques being used for using them. Unit testing is performed using White Box Testing, Functional testing is done via Black Box Testing, and Integration testing is carried out by using both the white box and black box testing. 
  3. As the level of testing the modules in an application or the intended software goes up, so does the complexity of carrying out the testing procedures. Since unit testing deals with testing individual units, it takes very little time and effort in comparison to the other two. Integration testing takes comparatively more time than unit testing because it involves the testing of two or more combined units of a system. At last, functional testing takes the longest time as the entire system’s functionality is checked at once. 
  4. Chances of error occurrence with the unit testing executed are less as the code is working and functionality is verified for individual units of the application. Going forward to Integration testing, the error chances increase a bit as the validation is performed on the working of a module (set of single units). However, functional testing is the one that is most vulnerable to errors as it focuses more on the business logic of the application and not the intermediate system states. 

Also read: Top Automation Testing Tools

Should You Prefer Automation Testing Over the Others?

It would not be wise to say that going with only integration testing would solve the purpose and save on the time and effort required for unit testing. Unit testing (manual/automation testing) is the fundamental block for carrying out Integration testing for an application. 

While in Unit testing, only a single developer or tester is held responsible in case of any error detection for a specified unit test for example, whereas as we go up towards the integration testing, the whole team assigned for the combined module loses its credibility for the neglected errors. Thus it is very important to follow and work through every step of the testing hierarchy in a software development cycle. Similar is the case between Integration testing and Functional testing. Let us explain this with the help of a very simple and practical example. Consider a scenario where a module is dealing with hitting the database, querying a piece of data, doing some processing, and then finally delivering the information to the end-user over the application. Now integration testing deals with checking if the code written is working fine and connecting to the database and querying the right set of data as expected without throwing any exception. On the other hand, functional testing will look only for the final output. 

Also read: Automation Testing Life Cycle

Types of Integration Testing

Below are the types of integration testing:

1. Big-Bang Approach

This is the simplest of all the other approaches as it involves the testing of all the modules of a system to be put together and tested for any error occurrence. Although the major challenge faced in this approach is error detection as it becomes very complex to find the associated module where the error might come from. Thus it is suitable for only small systems. 

2. Top-Down Approach

This technique works oppositely as compared to that of the bottom-up approach. Here the larger modules are tested first followed by the testing of the smaller ones. However, the major drawback of this testing technique is that the high-level modules that are largely dependent on the smaller-level modules that are not yet integrated would fail. And hence it involves the presence of many stubs (alternative pieces of code used in place of the systems which are not yet programmed or integrated).

3. Bottom-Up Approach

This integration testing technique involves the testing of smaller models first before the larger ones. Therefore, it is not suitable for the systems where there is a huge number of smaller sub-systems involved. 

4. Sandwich (Hybrid/Mixed)

This technique combines both the top-down and bottom-up approaches. Because of this, it helps in overcoming the drawbacks and challenges that come with these two approaches. However, it is suitable for large systems. The most challenging part of this approach is that it is high on the pocket as it involves top-son and bottom-up approaches together. 


By now it is quite clear that incorporating all the three kinds: Unit testing, Integration testing, and Functional testing would result in a more sustainable and robust product. Also, the availability of a variety of automation testing tools available in the market makes the jobs of the testers and the team onboard real easy to carry out such testing procedures. Skipping on any single testing technique might cause your business to incur huge losses and consumer loyalty.  

Also read: Automation Testing Trends

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