Levels and Types of Testing: Key Information for Testers
In today's article, we will focus on the levels and types of tests, which are key pieces of information for every tester. Understanding these concepts is not only important but essential for having meaningful discussions about the testing process. I want to emphasize that although definitions of test levels and types can be easily found on the Internet, it is more important to understand the relationships between them.
Often during job interviews, questions about levels and types of tests are among the first to come up, especially for candidates with an ISTQB certificate.
Many candidates with this certificate have answered questions about types of tests by listing various terms, such as exploratory, performance, regression, white-box, and black-box tests, in random order. While these answers are correct, it would be better for candidates to present their answers in a more structured way.
To begin with, there are four basic levels of testing that we should discuss:
1. Unit Tests
Unit tests focus on the smallest, atomic parts of the system, such as individual functions of code or screens. In different industries and technologies, the definition of "unit" can vary, but it always involves testing the smallest components of the system.
2. Integration Tests
Integration tests are the next level, where we check how these small "units" interact with each other. We focus on the interfaces of these units, checking if they are compatible.
3. System Tests (End-to-End)
At this level, we have the entire system integrated and check whether we can test the whole process from beginning to end.
4. Acceptance Tests
These are tests usually performed by the customer - not the company delivering the software, but the one buying it. In acceptance tests, we check if the system actually fulfills its purpose.
It's important to start the discussion about types of tests by discussing these four levels, as they are the foundation for any testing process. We always start with the smallest units (unit tests), moving through their integration (integration tests), checking the entire system (system tests), and up to the final acceptance (acceptance tests). These levels of testing are applied in practically every software development company.
Understanding these levels will allow for a better grasp of the different types of tests that can occur at each of them. However, before we move on to discussing types of tests, it is worth understanding how software is created in the first place, as it is from this process that the hierarchy of tests arises: unit, integration, system, and acceptance.
When creating software, we start with the smallest units - pieces of code that are then combined and integrated to form a larger system. At each stage of this process, we conduct appropriate tests to ensure that everything works correctly. Unit tests focus on individual pieces of code, integration tests check how these pieces work together, system tests analyze the entire system, and acceptance tests confirm that the system meets the client's expectations.
Understanding these levels and their relationship to the software development process is crucial for effective and sensible testing. In the next post, we will discuss different types of tests that we can conduct at each of these levels.
Different Types of Tests
Software testing is an integral part of the application development process. To ensure that our software operates correctly, we must perform various types of tests. Each of these tests has its unique features and purpose. In this article, we will discuss several basic types of tests that we can conduct at different levels.
1. Unit Tests
Unit tests are the most basic type of test. They involve checking whether individual units of code, such as functions or methods, work correctly. Unit tests are usually written by developers and check if individual code fragments execute as expected.
2. Integration Tests
Integration tests check whether different software components work together correctly. They involve testing the integration between modules, services, or systems. The aim of these tests is to ensure that the whole works as expected and that the individual components are compatible.
3. System Tests
System tests are conducted on an already integrated system. Their goal is to check whether the entire application operates according to requirements and meets user expectations. System tests can cover various aspects such as functionality, performance, security, and usability.
4. Acceptance Tests
Acceptance tests are conducted by the client or end-user to assess whether the software meets their expectations and requirements. The aim of these tests is to ensure that the software is ready for use and meets all established acceptance criteria.
5. Performance Tests
Performance tests check how well our software handles performance and scalability. The aim of these tests is to evaluate how quickly and efficiently the application operates under different loads. Performance tests can include checking response times, server load, or resource usage.
6. Security Tests
Security tests aim to check whether our software is resistant to attacks and protects confidential data. They involve identifying potential security gaps and attempting to exploit them. Security tests can include checking vulnerabilities to attacks like SQL Injection, Cross-Site Scripting (XSS), or Denial of Service (DoS) attacks.
7. Usability Tests
Usability tests check how easy and intuitive it is to use our software. The aim of these tests is to assess whether the user interface is clear, whether features are easy to find, and whether users can comfortably navigate the application. Usability tests can include user studies, interface analysis, or ergonomics testing.
These are just a few examples of the types of tests that we can conduct at different levels. There are many other testing techniques and approaches that can be applied depending on the needs and characteristics of the project.
In the next article, we will discuss in more detail the different types of tests and provide examples of their application at various levels.
Summary
Software testing is an integral part of the application development process. Different types of tests allow us to check various aspects of the software, such as functionality, performance, security, and usability. Conducting appropriate tests at different levels ensures that our software operates correctly and meets user expectations.
Frequently Asked Questions
- What are other types of tests not covered in the article?
- What are the most important features of unit tests?
- What are the main goals of integration tests?
- What are the most important aspects checked during performance tests?
- What are the basic methods of software security testing?
Ask a question if you have any doubts or want to get more information about software testing.