Software testing is a key building block if software is to be reliable in day-to-day use, easy to extend and economical to operate. For clients, this is not about technology for technology’s sake, but about fewer surprises during the project, traceable quality and a better basis for maintenance and further development.
This article explains the main types of software testing, where they are used in a project and the typical questions decision-makers have before or during a software project. A software test is a planned check used to verify whether an application works as expected and whether changes in one area trigger unnoticed problems elsewhere.
If you would like to assess a project, you can find suitable starting points via an overview of services, a rough cost range, a project brief with follow-up questions, an initial no-obligation consultation and insights into reference projects.
Why software testing matters for clients
The quality of software does not only become apparent shortly before go-live. It develops step by step during implementation and must be deliberately built up, checked and safeguarded. That matters for clients because many later issues do not first show up during operation, but can already be identified earlier in the course of the project.
Well-tested software is generally easier to maintain. When changes are needed, they can be checked more precisely instead of relying on assumptions. This is particularly relevant if an application is to be developed further over a longer period or adapted to new processes.
Software testing also plays an important role when extending a system. As new features are added, it helps to check existing processes as well and spot unintended side effects earlier. This makes it clearer whether a new feature only affects the intended area or has consequences elsewhere.
From a cost perspective, the principle is simple: errors discovered late often lead to more coordination, corrections and rework than issues that are spotted early in small steps.
From the perspective of specialist departments, tests do not just safeguard technical functions, but also business processes, for example:
- approvals
- inputs
- calculations
- notifications
The important point is to put this in context: tests do not replace good planning and design. They complement it as a way of reliably checking requirements during the project. At the same time, software testing can reduce risks, but it cannot guarantee absolute freedom from errors.
What types of software testing there are
Different types of tests examine software at different levels: from a small component through to a complete user journey. For clients, this distinction is useful because not every test answers the same question. Some checks safeguard individual rules, while others test how entire processes work together.
The main types of testing are:
- Unit tests check small, clearly defined parts of the logic in isolation. This allows business rules, calculations or conditions to be verified early on.
- Integration tests check how several components work together. A typical question is whether the application, database or an external interface interact correctly and pass data properly.
- System tests look at the application as a whole. They check whether key functions work together as expected for the intended use.
- End-to-end tests recreate typical user journeys from the users’ perspective. This may include, for example, a process from logging in to entering data through to completing a task.
It is also important how testing is carried out:
- Manual tests are useful where people need to judge whether a process is understandable, coherent and practical to use. This often concerns usability, sequences or whether inputs and results are easy to follow.
- Automated tests run repeatedly according to defined rules. They are particularly suitable for checks that recur regularly after changes and therefore need to be repeated reliably.
Another term that often comes up in projects is regression testing. This means repeated tests after changes. They check whether areas that were already working still function correctly and whether new changes cause unwanted side effects.
In practice, a robust testing approach is usually created not by a single type of test, but by an appropriate combination.
When which tests make sense in a project
The benefit of software testing increases when tests are not all left until the very end, but are used to match the individual project phases. This means quality is not just checked, but built up step by step.
Even during the requirements phase, it should be defined how it will later be recognised whether an outcome is correct from a business point of view. If goals, processes and expectations are described in a testable way, this creates a clearer basis for development and acceptance.
During concept and design, testing priorities can be defined early. These include above all:
- critical business processes
- interfaces to other systems
- important data flows
- areas with a greater need for coordination
During implementation, small and frequent checks are particularly useful. They help to detect errors closer to their cause instead of only finding them much later in a larger context. This often reduces additional coordination effort.
Before go-live, the focus shifts more strongly to the overall interaction. At that stage, key end-to-end processes, roles, inputs and outputs are reviewed together again in a targeted way. This makes it possible to check whether the application works coherently in its intended usage context.
Tests also remain relevant during operation. As soon as enhancements, technical updates or new integrations are added, both existing and new processes should be checked again. This is particularly true when software is expanded over a longer period.
In integration projects, integration tests are especially important. When several systems work together, problems often arise at handover points, in data formats or at process boundaries.
In bespoke software projects, coordination between the business side and development is especially important. The more closely processes are tailored to your company, the more precisely it should be defined what will later need to be tested as correct, complete and suitable for practical use.
How tests strengthen the technical foundation for later changes
CI/CD describes a workflow in which changes are regularly merged, checked automatically and prepared for further deployment.
For decision-makers, what matters most is why this automation counts: recurring checks can be run reliably with every change, without the same manual effort having to be repeated each time. This creates a clearer basis for assessing changes quickly and spotting side effects earlier.
In projects involving .NET, SQL databases, Azure and Azure DevOps, automated tests can form part of a transparent development process. This means quality is not only checked at the end, but continuously carried along with every change. This is particularly relevant for maintenance and further development where software is intended to be extended over many years.
This approach is especially helpful where several areas interact:
- In an enhancement that connects Azure DevOps with planning software, reliable checking of handovers and processes is important because otherwise changes can affect several systems at the same time.
- In a web platform for managing sewer networks, condition data and measures, what matters is that data, views and processes work together in a way that can be clearly understood.
- In a CRM system for an insurance broker, thorough checks are important wherever master data, cases and recurring processes come together.
Software built sustainably benefits when tests are not added afterwards, but are considered an integral part of the development work from the outset.
Frequently asked questions about software testing
Which software tests are really necessary for a bespoke software project?
That does not depend on a fixed standard checklist, but on the purpose, risks and complexity of the project. What matters is which processes are business-critical, which interfaces are involved and where errors would have particularly noticeable consequences.
In many projects, a combination of the following makes sense:
- checks of individual business rules
- tests for interaction with databases or interfaces
- checks of key end-to-end processes
- manual business testing by the future users
The more bespoke the software, the more important it is to derive testing priorities from the actual processes.
At what point should software testing be planned into a project?
Ideally from the very start of the project. Software testing works best when it is already clear in the requirements and concept phase what will later count as a correct result. In that case, tests are not just used for checking at the end, but as guidance throughout the entire implementation.
If testing questions are only raised shortly before go-live, ambiguities are often discovered too late. Tests planned early, by contrast, help to align expectations better between the business side and development.
Do automated tests replace business checks by users?
No. Automated tests and business checks serve different purposes. Automated tests reliably check recurring rules and technical processes against fixed specifications. Business checks by users remain important where it is necessary to judge whether a process is understandable, complete and practical in day-to-day use.
The two complement each other: one side provides repeatability, the other practical business suitability.
Why does software testing affect later maintenance and enhancement costs?
Because changes are easier to assess when reliable checks are in place. Without that basis, the effort required for analysis, coordination and manual follow-up checks often increases significantly.
Tests help to:
- check existing functions again when changes are made
- identify side effects earlier
- assess adjustments with greater clarity
This is particularly relevant for software that is intended to be extended over a longer period.
How can the testing effort for a planned project be estimated roughly?
For a rough assessment, the following questions are especially helpful: How many core processes are there? How bespoke are the workflows? Which interfaces, roles and data flows are involved? And how often are later changes expected?
These points make it possible to identify where testing is particularly important and where less effort may be sufficient. Testing effort is therefore not an isolated block, but part of the software’s complexity, risk and long-term use.
How to recognise a sensible testing approach
A sensible testing approach is not shown by having the longest possible checklist, but by whether business-critical processes are safeguarded in a targeted way. What matters is what has to work in live operation and where errors would have particularly noticeable consequences.
The key characteristics are above all:
- Requirements are described in such a way that the business side and development can later assess together whether a result is correct.
- Responsibilities are clearly defined: who carries out business checks, who provides technical safeguards and when which approvals are given.
- Testing does not end with the initial launch, but continues when changes are made, so that quality is also considered during further development.
- Interfaces, data imports and AI functions are looked at separately because they create additional dependencies.
This classification is particularly important for AI functions. If software works, for example, with Azure OpenAI for searching company knowledge, assistants or document extraction, inputs, results and integration into business processes should be tested in a targeted way.
If the project also touches on questions of data protection, contracts or accessibility, these topics should additionally be reviewed with a lawyer or data protection officer.