Condition-based test design: what is it and how to use it?

What is condition-based test design?

Condition-based test design is all about testing different conditions or situations that your software may encounter. Imagine your software making decisions based on user input.Condition-based testing ensures that you carefully consider and test all these decision points.

Simply put, you check whether your software behaves as it should under a variety of different conditions.

Why should you use it?

Oké, why would you want to use this technique? Because it helps you detect bugs you might otherwise miss. By applying condition-based test design, you ensure that you not only test the 'happy path', but also those less obvious scenarios. That way, you end up delivering a higher-quality product.

Practical tips for implementing

Let's get practical. How do you get started with condition-based test design? Here are a few steps to get you started:

• Identify conditions: First, look at the various decision points in your software. These could be if-else statements, switch cases, or other decision logic.
• Make a condition list: Write down all the possible conditions you haveïdentified. Think of all the different inputs and situations in which your software has to work.
• Design your tests: For each condition, create a test case. Yes, it's some work, but trust me, it's worth it. Make sure you test all the different combinations of conditions.
• Automatise where possible: Nobody wants to manually run all those tests. Use test automation to run your test cases efficiently. Tools such as Selenium or JUnit can help with this.
• Review and improve: Let others review your tests and don't be afraid to ask for feedback. There is always room for improvement.

Examples from practice

Let's look at a real-life example. Suppose you have an application that needs to manage user access. The conditions might be: the user is logged in, the user has admin rights, and the user is trying to access a particular page. By applying condition-based test design, you test all possible combinations of these conditions to ensure that your application always behaves correctly.

Condition-based test design techniques

There are several techniques within condition-based test design that you can use. Here are four key techniques:

• Control flow testing: Testing the flow of control in the application.
• Semantic testing: Testing the meaning and behaviour of conditions.
• Elementary comparison testing: testing basic comparisons within decision points.
• Decision table testing: used to test all possible combinations of conditions.

Coverage types for condition-based testing

With condition-based test design, you use different types of coverage to ensure the quality of your tests:

• Condition Coverage (CC): ensures that each condition is at least één times true and één times false.
• Decision Coverage (DC): Ensures that every decision in the code is at least één times true and één times false.
• Condition Decision Coverage (CDC): Combines CC and DC.
• Modified Condition Decision Coverage (MCDC): Ensures that each condition can separately affect the outcome of a decision.
• Multiple Condition Coverage (MCC): Tests all possible combinations of conditions.

Example of condition decision coverage

Let's keep it simple with an example. Suppose you have a decision point where you control access to an attraction. The conditions are whether a person is taller than 120 cm and heavier than 50 kg. With condition decision coverage, you make sure that all possible combinations of these conditions are tested.

Get started with your software!

Maybe now you're thinking, "This sounds like a lot of work." True, but think of it as an investment in the quality of your software. By paying extra attention to testing now, you will avoid costly mistakes and disappointed users later. And let's face it, who doesn't want to deliver a product that is really well put together?"

Follow your e-learning at Testlearning

Want more information about this way of testing? Then follow your E-learning TMAP®: Quality for cross- functional teams at Testlearning.net. Good luck with testing and don't forget that you can always ask questions or share your experiences. We are here to help each other and get better at what we do. Happy testing!