Most developers have no implication in the actual testing process of a software, but truth be told, knowing a few basics of testing should be mandatory for all successful software developers. Most developers who have started out as testers and are now thriving in their business have said that they owe most of their success to what they learned during that time.
Some developers who never worked at testers don’t fully understand why tests are so important. Their purpose is not to find bugs, but rather reduce the risk for the client to encounter issues while using the software. There are numerous types of testing, each serving its own purpose. Below, you will find the most common types and what they are used for.
Black Box Testing
One of the most common types of testing, black-box testing revolves around a simple rule. The testing itself id not concerned with how the outputs are derived. Its purpose is to test if a certain set of inputs produces a certain set of outputs.
In black-box testing, you are not interested in the actual code or how that code works, only in the results produced. To put it simply, you only need to know if the test works or not. If the outputs produced are the ones you were expecting, then the code works. If not, then no, and it needs to be modified.
One of the greatest advantages of black-box testing is that it is quite simple to execute and it does not require the tested to be a person specialized in tech. On the other hand, it holds the great disadvantage of not showing the actual reason for errors which makes it quite limited.
White Box Testing
As opposed to black-box testing, white-box testing, also known as clear box testing, involves having access to the actual code, or at least knowing some of the software’s internals. White-box testing is usually applied to unit testing, but can also be applied to integration and system testing.
With this type of testing, the tester has the liberty to choose inputs and observe their paths towards the appropriate outputs. White-box testing has the advantage that it can discover bugs faster and allows for the code to be optimized accordingly. At the same time, the tested needs to have at least some basic coding knowledge and have access to the actual code.
Sometimes known as a user acceptance testing (UAT), this type of testing requires for the tester do examine both the requests of the client and the software as a whole. The acceptance testing can either test the overall functionality of the system or its usability, and sometimes both. The purpose of it is to compare what the client expects from the software and what it actually delivers.
An acceptance test is performed once the entire software is complete, to see if it meets the requirements of the client and can often be performed in the form of black-box testing. It is the last lever of testing and is usually performed before the software is ready to use. One disadvantage of acceptance testing is that it cannot be tested in the testing environment and the set-up can be quite time-consuming.
Broadly speaking, any test that is executed and verified automatically is considered an automated test. No matter if you automate the testing of a web page, or of an API, as long as you run a script that performs a task and then checks the results, it is an automated test.
Nowadays, testing is slowly moving towards automation. The reason is quite easy to understand, as the process of continuously running test cases can become quite monotonous. Automated tests are less prone to errors and more cost-efficient, especially in environments where the Agile methodology is implemented. Instead of having someone run the same tests over and over again, over a certain period of time, to ensure everything works accordingly, it is much easier to design an automated test that simply flags an error when it happens.
As the name calls it, the sole purpose of regression testing is to ensure that the system does not regress in functionality. Regression testing is needed typically when new features are added to the software, or when the code is modified to fit a new set of requirements.
If you are familiar with Agile methodology, you are probably familiar with regression testing as well, as it is often required in this environment, because it allows for new features to be constantly added to the initial code.
Regression tests are usually automated, as they need to be performed quite often, especially when new features are added on a regular basis. If regression tests would be done manually, the costs would become unmanageable and ineffective in terms of time during testing.
All tests that are run to verify the overall functionality of a system are considered functional tests. Contrary to many people’s beliefs, not all testing is performed to test the functionality of systems. Some may test user experience, while others may test security or performance.
Functional testing works based on quite a simple premise. You feed the test one input and then examine the output and make sure that the system meets the desired requirements. Again, it is a type of test that does not focus on how the process is happening, but rather on the results. This means that the tester is not required to know the code of the system to test it.
This type of testing gives the tester the freedom to investigate and discover potential bugs, as it does not involve actual scripted testing. The functionalities of the system are not checked in a structural manner, but rather ad-hoc, which is why exploratory tests are often recorded. This way, if a bug is discovered, the path that the tester has taken can be retraced.
Exploratory tests can not be automated, as they are more based on a cognitive structure. You are basically thinking and testing at the same time, making it more of an approach, rather than a method.