Which tools should every software tester know?

Software testing

What is software testing?

Software testing is a process to evaluate the functionality of a software application. It is used to determine whether the developed software meets the specified requirements or not. We also use software testing to identify deficiencies and thus ensure that the product works largely without errors.

There are a variety of software testing methods for this. With the help of software testing tools, almost any software can be tested and thus the software quality can be ensured - both manually and automatically.

Why is software testing so important?

In order to understand the importance of test procedure software, we have explained the four most important points below.

1. Software testing saves money.

Software development consists of many phases (conception, development, testing implemented in sprints if one proceeds according to agile methods in software development) and if errors are discovered in the early phases, it is usually cheaper to fix them. It is therefore important that the tests are carried out as early as possible - Test Driven Development even stipulates that the tests are written before development, which is particularly important for complex and validated environments.

2. More security.

There have been many situations in the past where user information has been stolen or hackers have found it and used it to their advantage. That's why people look for products that they can trust, that they can rely on and that have been extensively tested for functionality and security. Our personal data should be treated as confidentially as possible. Security testing gives the user a trustworthy product, as problems and risks are identified in advance and eliminated during development.

3. Better product quality.

In order for the product vision to become a reality, the result must meet the requirements of the users in the best possible way. Compliance with product requirements is to some extent essential as it helps in achieving the desired end results. Digital products should offer their users added value and support them in completing certain tasks (use cases) faster, easier and more efficiently. It is therefore very important that digital products actually and continuously deliver this added value - and ideally also after a new update, i.e. after a mostly comprehensive change to the software.

4. Greater customer satisfaction.

The primary goal of a product owner is to achieve the best possible customer satisfaction when using his digital product (usually achieved through an agile process model and a UX design that is tailored to it). This is also the main reason why apps and software should be tested - to ensure the consistency of the requirements over the entire product life cycle). Customer trust is not easy to earn, especially if the product has more bugs after new releases.

The purpose of software testing

Software test procedures provide us with valuable information and insights into the state of the system. When deciding whether a product will be launched on the market, the stakeholders need to know, for example, the condition of the product in terms of its requirements, security guidelines, etc. This includes aspects such as the conformity of the product with the requirements, user friendliness and compliance with the applicable regulations by the product.

Tests are used to verify that the system meets various requirements, including function, performance, reliability, and safety.
In addition, the aim is for the selected test procedure to check software with regard to all other criteria to be validated.

Software tests help improve the quality of the product. Finding bugs is one of the purposes of software testing, but it's not the only purpose. It is important that software tests verify and validate that the product meets the stated requirements and specifications.

When we talk about software quality, we are basically talking about the evaluation of the software based on certain attributes. A software QA is defined based on the examination of external and internal characteristics of the software. The external software QA is defined in terms of the way the software works in real time in run mode and how useful it is to the user. The internal software QA, on the other hand, focuses on the internal aspects that depend on the quality of the written code.

The meaning of error, fault, bug and failure

Software testing describes the process of identifying bugs, where a bug is a discrepancy between actual and expected results. An error can be divided into the following categories:

AError is a mistake on the part of the software developer. This includes software engineers, programmers, analysts and testers. For example, a developer can misinterpret certain information or a programmer enters a variable name incorrectly. This then leads to an error when executing or compiling the software.

ABug is the result of a coding error. It is a programming error which means that a program can be executed, but the required function does not work or does not work properly, provides incorrect results or crashes. A bug in the software or hardware causes the program to malfunction.

AFailure is the inability of a software system or component to perform its required functions within certain performance requirements. If a defect reaches the end customer, it is called a failure.

AFault is an incorrect step, process, or data definition in a computer program that causes the program to execute incorrectly. It is an anomaly in the software that could cause it to not behave according to its specification.

What software testing methods are there?

Each type of testing also has its own characteristics as well as advantages and disadvantages and is used for different tasks. Below, we'll mainly cover the types of software tests that we use the most. This includes functional tests and non-functional tests.

Functional tests

This is a type of black box test based on the specifications of the software being tested. The application is tested by providing input in the form of inputs by the user or via interfaces by other systems. Then the results are examined, which must match the functionality for which it was intended. The functional test of a software is carried out on a complete, integrated system in order to assess the compliance of the system with the specified requirements.

There are five steps involved in testing an application for functionality:

1. Determining the functionality that the intended application is intended to provide.
2. The creation of test data based on the specifications of the application.
3. The output is based on the test data and the specifications of the application.
4. Writing test scenarios and executing test cases.
5. The comparison of actual and expected results based on the executed test cases.

Non-functional test types

Non-functional testing involves testing software against the requirements that are non-functional but are important, such as performance, security, user interface, and so on.

Below are some of the important and commonly used non-functional test types.

APerformance test is mainly used to identify bottlenecks or performance problems (performance problems) instead of finding bugs in software. There are several causes that can contribute to slow software performance. This includes:

  • Network delay
  • Client-side processing
  • Processing of database transactions
  • Load balancing between servers
  • Data playback

The performance test is one of the most important and mandatory test types with regard to the following aspects:

  • Speed ​​(response time, data playback and access)
  • capacity
  • stability
  • Scalability

Automated testing vs. manual testing

Software testing can be broken down into two areas: manual testing and automated testing. Both manual and automated tests have advantages and disadvantages.
In manual testing, test cases are executed manually by a human and without the assistance of tools or scripts. However, with automated testing, test cases are executed using tools, scripts, and software. The type of exam will depend on a number of factors including project requirements, budget, timeframe, expertise, and suitability. If software is continuously developed and the complexity of the requirements grows with each release, automated tests are the better choice because you save time and budget over the course of the project.

The advantages and disadvantages of static testing

In static test procedures, the tester checks the code, the architecture documents and the requirements document, and then makes comments about the review of the document. Security tests are performed on software that is inoperative and inactive to analyze the software in a non-runtime environment. This type of test is useful for detecting code errors. Static testing takes place early in the development cycle, so it is also known as a verification test. Requirements specifications, design documents, source code, test plans, test scripts, test cases and website content, all of these must pass the static test. Proper static testing can detect around 85% of software errors. In a continuous integration environment, static test procedures are usually an integral part of a build process.

The advantages of the static software test procedure:

  • Helps in identifying the errors in the code.
  • The tests are carried out by trained software developers with a good knowledge of programming, in some cases this is also possible automatically.
  • It's a quick and easy way to find and fix obvious bugs.
  • With automated software testing tools, the software can be scanned and checked quite quickly.
  • The use of automated software testing tools offers recommendations for reducing risks.
  • Static testing makes it possible to find bugs early in the development lifecycle, which in turn reduces the cost of fixing them.

The disadvantages of the static software testing procedure:

  • Manual processing takes a lot of time.
  • Automated tools only work with a few programming languages
  • can deliver false positives
  • only scan the code, but do not check it during execution
  • cannot detect any weak points that could lead to problems at runtime.

The advantages and disadvantages of dynamic software testing

In contrast to static testing, dynamic testing executes the code. The test checks both the functional behavior and the CPU load as well as the overall performance of the software. The goal of dynamic testing is to ensure that the end product is designed according to customer requirements and works exactly as it should. It is also known as a validation or execution test.

The advantages of the dynamic test method

  • Helps identify weak points in a runtime environment.
  • Helps you analyze applications even when the tester does not have the actual code.
  • Identifies vulnerabilities that are difficult to find with static code analysis.
  • Allows static code analysis results to be validated.

The disadvantages of dynamic testing

  • Can give false assurance that everything has been checked.
  • Generates false positives and false reports.
  • It's difficult to keep track of the vulnerability in the code.
  • It takes longer to fix.
  • This makes it more costly.

Dynamic tests validate the results with the expected result. It is carried out at all levels and can be done either in the form of a white box test or the black box method. In the following, we will go into more detail about the two methods and provide a black box test example from practice to illustrate this.

The white box test

The white box test is based on knowledge of the internal logic of the code of an application. A white box test describes the detailed examination of the internal logic and structure of the code. White box tests are also known as glass tests or open box tests. In order to be able to perform white box tests for an application, a tester must know how the code works internally. The tester has to take a look at the source code and find out which unit of the code behaves unexpectedly and therefore incorrectly in relation to the specification.

The black box method

With the black box method, the internal system design is not taken into account and remains unknown to the tester. The tests are based on the requirements and functionality that are tested with inputs via the interface or interfaces to the software. It is called the black box method because there is no knowledge of the inner workings of the application. The tester has no access to the source code and is not aware of the system architecture. Typically, while performing a black box test, a tester interacts with the system's user interface or other interface by providing inputs and examining outputs without knowing how and where the inputs are being processed.

Black box test example

Several approaches are used in the black box test procedure. This includes, among other things, error, status and limit value-based testing procedures. A black box test example is equivalence class based testing. The use of equivalence classes as a basis for the functional test is suitable if a thorough test is desired or if it is urgently necessary to avoid redundancies.

Other important software testing methods

Function testing

This type of test ignores the internal components and only focuses on the output to check whether it meets the desired requirement or not. This is a black box test procedure that is geared towards the functional requirements of an application.

Non-functional testing

This type of test has its own team, usually referred to as the Non-Functional Test (NFT) team or the performance team.

Non-functional testing includes testing non-functional requirements such as load testing, stress testing, security, volume, recovery testing, etc. The aim of the NFT test is to ensure that the response time and other previously listed properties of the software or application meet the requirements.

It shouldn't take a long time to load a page or system. In addition, this should be maintained even during the highest workload. It is necessary to define what “does not take up much time” means.

Visual regression tests

Visual regression tests are a way of taking screenshots of the developed website and comparing them in different versions. These screenshots are often taken before and after the front-end code is updated. The screenshots can be taken at any time, whether during testing, staging or in production. You can then compare previous and current screenshots to see whether the latest updates have changed anything in the software's interface. Visual regression tests do not test any functions.

Smoke testing

Whenever a new build (executable software) is provided by the development team, the software testing team validates the build and makes sure that there is no major problem.

The test team ensures that the build is stable and that a detailed test run is carried out. Smoke Testing checks that there is no “blocker” in the build, which prevents the test team from testing the application in detail.

If testers find that the most important critical functionality does not work in the build or release phase (broken build), the test team can reject the build and inform the development team accordingly. Smoke testing is carried out down to a detailed level of all functional or regression tests.

Software testing with the top 10 testing tools

1. Selenium

Selenium is a popular tool for testing software in the browser. It is considered the industry standard for testing web applications by automating test cases in the user interface.

2. Katalon Studio

Katalon Studio is a powerful and comprehensive automation solution for testing API, web and mobile applications. It has extensive functionality for these types of tests and supports multiple platforms including Windows, macOS, and Linux.

3. UFT

UFT is a popular commercial tool for testing desktop, web, and mobile applications.A number of functions for API tests have been expanded.

4. TestComplete

TestComplete is popular for testing web, mobile and desktop applications because of its powerful and comprehensive capabilities. Testers can use JavaScript, VBScript, Python, or C ++ Script to write test scripts.

5. SoapUI

SoapUI is a functional tool that was specially developed for API testing.

6. IBM Rational Functional Tester

IBM Rational Functional Tester is a test automation tool designed for testing applications developed using various languages ​​and technologies such as Web, .Net, Java, Visual Basic, Siebel, SAP, PowerBuilder, Adobe Flex, and Dojo Toolkit.

7. Tricentis Tosca

This test platform provides a comprehensive set of tools to support most test activities ranging from test design and test automation to test reporting and analysis.

8. Ranorex

Ranorex has provided a comprehensive and professional suite of web, mobile, desktop and API testing functions for many years.

9. Postman

Postman is another automation tool designed for API testing. Users can install this tool as a browser extension or desktop application on Mac, Linux, Windows and submit web service requests to the software's API in order to then validate the result.

10. Apache JMeter

JMeter is an open source tool designed for load testing and performance measurement - two functions that JMeter is known for. The tool is now also used for API and service tests, especially for API performance tests.

When should you start testing?

Starting testing early reduces the cost and time of post-processing and creating bug-free software that is shipped to the customer. In the Software Development Life Cycle (SDLC), however, testing can be started and continued from the requirements acquisition phase to the provision of the software. Often times, agile projects just start writing tests before a line of program code has been written. In test-driven development, the tests are therefore already used as a specification.

It also depends on the development model used. For example, in the waterfall model, formal tests are performed in the testing phase, but in the incremental model, tests are performed at the end of each step size and the entire application is tested at the end.

During the requirements acquisition phase, the analysis and verification of the requirements is also considered a test.

Reviewing the design at the design stage with the intention of improving the design is also considered a test, they are often referred to as user acceptance tests.

Tests that are carried out by a developer after the code has been completed are also classified as tests; code reviews and pull requests are often used here.

When should you stop testing?

It is difficult to determine when to stop testing because testing is an endless process and no one can claim that any software has been 100% tested. The following aspects must be taken into account when the inspection process is interrupted:

  • Test dates
  • Completion of the test case execution
  • Completion of the function and code coverage up to a certain point
  • The error rate drops below a certain level and no high priority errors are identified.
  • After each development phase z. B. After a sprint in agile projects, a test phase is planned.


Software tests are an important part of the software development process, without which quality in software development is hardly possible. It is not a single activity that takes place after implementation, but rather part of every phase of the software lifecycle. A successful test strategy begins with consideration in the requirements specification. As with the other activities in the software lifecycle, testing has its own set of challenges. As software systems become more complex, the importance of effective, well-planned test effort and the use of test automation tools will continue to grow.