Types of testing overview

Type of testing, according to the ISTQB (International Software Testing Qualifications Board) – a means of clearly defining a specific level goal for a program or project

Testing type is aimed at the specific goal of testing, which can be the function check that is performed by the component or the system in general. The aim of testing can be directed on the non-functional element check  (reliability,  user-friendliness), structure, component architecture, or system in general, for example, testing whether the defect was fixed ( confirmation checking or retesting)  or the regression testing.

Depending on the demand the process of testing must be organized accordingly. Thus, we can define 4 types of the software testing:

• Functional testing;
• Non-functional testing;
• Structural testing;
• Change-related testing.

Functional testing

Nowadays it is hard to underestimate the importance of functional testing because this action is aimed at testing all functions of the system to confirm that each function is working in accordance with the documentation.

Functional testing elements:

• preparation of the testing data based on the created documentation;
• business requirements as part of the functional testing;
• receiving results based on the specification;
• execution of test cases.

Functional testing can be performed in accordance with the specifications and also on the basis of the business process, which means according to the knowledge of the system.

Advantages of the functional testing:

• in terms of testing we «copy»  the actual usage of the system;
• this kind of testing, as a rule, is performed under conditions that are very close to the real ones.

Disadvantages:

• there is a possibility to make some mistakes in software logics during the testing process.

Non-functional testing

In terms of the functional testing we answer the question whether the system works in general, accordingly in terms of the non-functional testing the question is  «How good does it work?».
Non functional testing is aimed at checking those aspects of the software, that can be described in the documentation, but they are not the functions of the program products

Non-functional testing consists of the following subtypes:

1. Stability/Reliability testing –  is aimed at checking the crashes during the usage.
2. Usability testing – the exploration of software usability.
3. Efficiency testing – a check of all the necessary amounts of the code and the QA resources that are used by the program to perform the separate function.
4. Maintainability testing –  a subtype of the non-functional testing which indicates how easy it is to support the efficiency of the system. 
5. Portability testing – a check that focuses on the ability to transmit one component or all the software to another environment  (Windows 8.1 -> Windows 10, Windows -> MacOS).
6. Baseline testing – a documentation and specification check, according to which the test cases are going to be written.To this subtype we can refer to requirements testing. 
7. Compliance/Acceptance testing – checking the product for compliance with readiness criteria.
8. Documentation testing – checking of all documentation created during the testing process ( starting from the test plan to test-cases).
9. Endurance testing – testing the system under high load for a long period of time to study its behavior.
10. Load testing – usually performed to determine the behavior of the software below the expected load level.
11. Performance testing – checking the speed of the software or its individual functions.
12. Compatibility testing – system testing while working in different environments: «hardware», software part, etc.
13. Security testing – is conducted to answer the question «Is the application safe / secure or not?».
14. Volume testing – software testing using databases of a certain size.
15. Stress testing – this is testing in limited conditions, for example, checking system behavior (no crashes) in case of lack of computer resources (RAM or space on HDD / SSDs).
16. Recovery testing – is performed to determine the speed of system recovery in case of a software crash or «hardware»  error.

Localization testing – checking the software for compliance with linguistic, cultural and / or religious norms. Localization checks the display of all translated software texts.

Structural testing

Structural testing is aimed at the testing of the system structure or the separate component. This type of testing, as a rule, is related to the «white box» testing and «black box» testing, as we are checking what is happening inside of the system or the application.

Structural testing methods:

1. Statement Coverage – a check of all operators in the program while using it (at least once).
2. Path Coverage – a test method designed to meet the criteria for covering each logical path through the program.
3. Branch Coverage – checks whether each branching condition has valid or false values ​​for the program.
4. Condition Coverage – a method similar to Branch Coverage, the main difference is to check the state of coverage for conditional and unconditional branches.

Advantages:

• ability to detect and delete «extra» code;
• ability to identify the potential defects on the early stage;
• provides more thorough software testing; 
• does not require high man-hours.

Disadvantages:

• requires knowledge of code and testing tools.

Change-related testing

When testing changes in the system it is very important to understand the difference and the line between the concepts of regression testing and retesting.

Regression testing is performed in order to check the functionality of the existing functional and to check for any defects after corrections or additions to the system.

Retesting is performed to confirm the correction of the error and the operation of this functionality.

Regression testing

Advantages:

• confirms the absence of bugs after adding a feature or editing the code;
• can be performed using automation tools;
• helps to improve the quality of the product.

Disadvantages:

• this type of testing can be very time-consuming.

Retesting

Advantages:

• confirms error correction and correct operation of the functionality;
• improves the overall quality of the product;
• requires less time for verification;
• does not require any new test environment settings.

Disadvantages:

• requires a new build to verify the defect;
• test cases for re-testing can be detected only after the first round of testing;
• test cases for re-testing cannot be automated;
• requires additional time to pass the previously passed test cases.

Knowledge of the types of testing is a necessary skill of the tester, it gives an understanding of approaches to software testing, helps to plan testing well, as well as to classify the errors found.