Modern Software QA & the Importance of Requirements-based Testing

With digitalization, software quality assurance has become a crucial part of virtually every product manufacturing process, regardless of what you produce, the industry you work in, or the size of your company. But for a very long time, QA teams operated separately from developers, jumping in after development finished to provide the final parameter and defect checks before code went into production. Increasing product complexity and Agile ways of working have radically changed that. Read on to learn more about modern software QA processes and the role requirements-based testing has to play in the evolution of the field!

The state of software quality assurance until now

In previous years, organizations relied heavily on Waterfall software development, in which no working software is made available during the development cycle. In other words, Quality Assurance (QA) was an afterthought, and testing was started after development was done, meaning less flexibility to change requirements and more often than not, nonalignment between QA and development teams.

However, as products became more complex and market demands more exigent, QA was forced to evolve to keep up with new and Agile ways of working. Instead of just being a stand-alone step at the end of the software development process, organizations had to start incorporating Quality Assurance throughout the full lifecycle of the product, to provide code releases both at speed and at a high quality.

Evolving from quality assurance to testing engineering

With this deeper incorporation into the software development process came greater responsibilities, too. Instead of just identifying and reporting defects, QA professionals are now expected to:

• Help improve overall product engineering techniques
• Find better ways of collaborating as a team
• Create and uphold an organization-wide culture of quality

And as a whole, move from isolated software Quality Assurance to testing engineering, i.e., the process of continuous evaluation using automated tests. This requires a different approach and toolset, especially due to the frequent changes in planning, requirements, and resource allocation – meaning that testers and developers need to be aligned throughout the process.

Requirements-based testing is a great way to achieve this much sought-after alignment and traceability, and ultimately, build high-quality products.

Meet requirements-based testing

Requirements-based testing is an approach in which both functional and non-functional test cases, conditions, and data are derived from the project requirements. The main goals of requirements-based testing are to:

• Validate that requirements are clear, fully thought out, accurate, and consistent
• Figure out the least amount of test cases needed to make sure that the code meets said requirements
• Ensure that the software will do what it is intended to, and nothing else (i.e., that it fulfills its stated purpose)

Key benefits of requirements-based testing

There are many benefits that come along with requirements-based testing, which is why multiple functional safety standards require it. For example, DO-178C (a standard for aviation software development) highlights the efficiency of requirements-based testing and even insists that all tests must be requirements-based. 

Here are some of the key benefits of requirements-based testing that are worth keeping in mind if you are considering taking your software QA efforts to the next level:

Ensures well-defined requirements

Basing testing activities on requirements helps ensure that the requirements themselves are clear, comprehensive, and well defined. At the end of the day, taking that second look at the project requirements will go a long way to avoiding costly rework and making sure everyone is on the same page going forward.

Promotes high-quality software

Testing software against requirements promotes a higher quality end product. How? It makes sure the software performs as it was intended, holds it to a high standard of quality, and constantly bears user and business requirements in mind, meaning that ultimately there will be a higher level of stakeholder satisfaction.

Facilitates traceability and by extension, compliance

Linking requirements to test cases helps facilitate traceability. This means that stakeholders will be able to understand what the tests cover and track changes as well as the impact said changes have. This is also a huge help when it comes to complying with functional safety standards, many of which actually list requirements-based testing as a must-have.

What is the requirements-based testing process?

Now that we’ve explored the benefits of requirements-based testing, let’s have a look at the different steps involved in the process.

1. Defining Test Completion Criteria: Also known as establishing your Definition of Done. This means that testing is only complete when the goals you agreed on have been reached.
2. Design Test Cases: Test cases are defined by five key parameters: the initial system state, existing data, inputs, expected outcomes, and then the actual outcomes. These test cases need to align with the requirements specified at the outset of the project.
3. Build Test Cases: After test cases are designed, they must be built. This is when the necessary data and testing components are put in place to carry out the tests.
4. Execute Tests: Next, the test cases are executed against the code which is being evaluated, and the results are meticulously documented.
5. Verify Test Results: Pretty self-explanatory. At this stage, the team verifies if the expected results and what you actually got match each other.
6. Verify Test Coverage: This step makes sure that the tests addressed both functional and non-functional elements of the requirement, as well as checking in on how much of the code was covered so far.
7. Track and Manage Defects: At this point, if any defects or bugs were detected through the testing process, they are addressed and resolved. This also generates defect statistics that showcase trends and indicate the overall status of the project.

Best practices for requirements-based testing

One of the main purposes of requirements-based testing is to make it easier to ensure high quality in complex products. However, if you’re just starting out, you might be daunted by the idea of changing how you run your testing processes. Here are a couple of fundamental best practices which define a good testing process and will help you hit the ground running:

Create an exhaustive test plan

This helps inform the rest of the team and make sure everyone is on the same page. It’s also useful for getting any necessary managerial support and stakeholder buy-in. 

Test early and test often

Start testing at the beginning of a project, when objectives are established and requirements are documented. If you have requirements, you can start requirements-based testing. 

Make sure the tests are effective

Tests should bring value to the project, not more headaches. Make sure that your tools and processes are well defined and provide good coverage of the requirements. Remember: prioritize quality over quantity.

Make it manageable

Having an accurate project status overview relies on your testing. Put the right processes in place to report on tests and track defects. Short, concise, and well-organized test cases help with manageability and traceability.

Ensure traceability

And last, but certainly not least: in order for your team to be able to link test cases to requirements, you need to have end-to-end traceability in place. Using the right tools helps make sure that there is a digital thread connecting all your work items from specifications through development all the way through to testing and release.

In order to ensure lifecycle-wide adherence to the highest quality standards possible, you need to have the right tool support. A robust Application Lifecycle Management platform like Codebeamer allows you to keep costs down while improving quality control, team collaboration, and testing insights across the board. It also makes your compliance efforts a whole lot easier, meaning stress-free regulatory audits (and who doesn’t want that?)