Once the software is designed, it is necessary to check it against every possible test case of every domain so that it might not face any issues once it is available to the users.

Testing, in simple words, is executing the software to find all the errors or bugs. To improve the user's experience, our application should be error-free. If the testing process is successful, it will remove all the possible errors from our software.

There are certain principles for testing procedures:

All the tests that will be performed should be approved by the customer and meet their requirements.
While designing the software, testing should be done by a third party.
Since we need some optimal amount of testing for risk assessment, Exhaustive testing is not possible
Proper planning should be done before implementing any tests
Testing should begin from the small parts, and then we should move towards the large parts
Testing follows the 80/20 rule, also known as the Pareto rule, which states that 80 per cent of errors come from the 20 per cent of program components.

Types of Testing

Software testing is basically checking whether the outputs or responses received from an application whether matches the expected requirements for the same application or not. In simple terms Software Testing generally means the verification of Application under test (AUT).

A defect free software is more reliable and secure this increases the performance and hence the demands of application.

Testing of software is classified into 11 types. Let us try to understand each of them one by one.

1. Unit Testing

As the name suggests, unit testing primarily focuses on the minor units of the software program. The testing process begins by testing the smallest unit or the group of interrelated units. The programmer tests the execution of each unit by using some sample inputs and checking its corresponding outputs with the already known results.

For Example,

Programmer checks whether the loop is working fine or not in a program.
Incorrect arithmetic precedence.
Initialization of variables is not done correctly.

2. Integration Testing

The main principle behind integration Testing is to build a complete program or software structure by integrating or combining all the basic parts that are already tested by the unit testing approach.

Based on the way the components are integrated to form the complete program structure integration testing into four types:

Top-Down Approach
Bottom-Up Approach
Sandwich Approach
Big Bang Approach

Examples of integration testing

Black box testing: In this approach we check the output directly without focusing on the internal working mechanism. It is usually used for validation of the software.

White box testing: This approach checks how does the software calculate output by focusing on the internal algorithms used to design it. It is usually used for verification purposes.

3. Regression Testing

When working on large products, some components are designed after the whole program and in order to maintain the validity of our software this type of testing makes sure that the complete setup is running fine after the newly designed feature or component is added.

For example, assume that we have a module staff, student module is designed recently and now it would be added to the already existing finance module, regression testing assures you that the software would still run after combining both the modules in regression testing.

4. Smoke Testing

As the name suggests, this technique is like a preventive approach. In this type of testing we make sure that the software is ready to be tested further. This name was used as this approach makes sure that the first step did not catch fire before moving on the next step

For example if the project you designed has two or more modules you should make sure that the first module works absolutely fine before moving to the next module.

5. Alpha Testing

This type of testing is usually done by the Quality Assurance employees, When the project is ready to be handed over to the client, this approach is usually used to check the proper working of our system. Alpha Testing is also a type of validation testing. This is also known as acceptance testing

For example: The alpha Testing for your software is done by the organisation itself to make sure the product is updated and would fulfill the user requirements.

6. Beta Testing

Unlikely as the Alpha Testing, the end users perform the test on the application to make sure that the product is capable of working. Beta test can be performed on more than one locations simultaneously by different users. Beta tests versions of certain applications are released specifically for a fixed amount of people so that the product can be tested in the real time.

7. System Testing

System Testing is usually done for large software products. In System testing we make sure that the product is capable to run on different operating systems without fluctuating. System Testing is an example of Black box testing as it focuses on the inputs given to the system and their corresponding outputs.

Based on the methods used to validate our product the system testing approach can be broadly divided into four parts

Stress Testing
Recovery Testing
Security Testing
Performance Testing

Note that System Testing includes both functional as well as join functional testing

Stress Testing
This is a specialised form of System Testing. In this type of testing we check the software against the unfavourable conditions to make sure that it can provide us with the suitable output and if not we try to observe what are the changes in its behaviour or internal working mechanism.

Usually in this approach we test the system on such test cases that would require the maximum amount of resources like storage or disk space.

Test cases that are most likely to cause thrashing when the program is being executed in any virtual operating system are also used to check the validity of software.

Performance Testing
When the client requires to check the run time capabilities like speed or effectiveness of a software, performance testing is the best choice. In this type of testing we check the run time performance of our program usually when a integrated system is used. It is also used to check the changes in the performance with respective loads in a system hence it is also referred to as Load Testing.

8. Object- Oriented Testing

To verify or validate an object oriented system we can use a combination of all the required types of testing.

It can be done in such a manner

Testing of Requirements
Design and Analysis of Testing
Testing of Code
Integration Testing
System Testing
User Testing

9. Acceptance Testing

This testing is done by the user that receives the product after its completion to make sure that all the requirements are satisfied.

Software Testing Index

Fundamentals