Most Common Mistakes and Challenges in Test Case Design

Sooner or later, the task of designing test cases falls on the table of every QA specialist, and having well-written test cases is essential for software testing. A good starting point is understanding how to create and maintain effective test cases. The next logical step is understanding what could go wrong while designing test cases and the most common challenges QA specialists might face. 

Whether you are a new software tester who has just started their journey in quality assurance (QA), or an experienced specialist with several years of expertise under their belt, it is worth taking your time to reflect on the whole test case design process and pay extra attention to the most common bottlenecks.

This blog article will focus on some of the most common challenges and mistakes testers and QA teams encounter during their testing processes, as well as how to overcome these pitfalls to ensure a smooth QA strategy.

Common challenges in test case design

Designing test cases isn't always as straightforward as it might seem at first glance. Some complications might be an obstacle even for the more experienced testers. It is critical to be aware of what might come your way when you are assigned the next test case design task. Let’s break them down:

Changing requirements

In a fast-paced environment, constantly changing requirements are not an exception to the rule. On the contrary, adapting and evolving products to the needs and wants of the end-user is a common practice. This constant change might make your test cases irrelevant before they are even used.

There is no escape from the change and evolution of products. Denying this might lead to bugs slipping into production because documentation was reviewed on time, and adjustments were not made in a timely manner.

For instance, a tester may prepare a full test suite based on initial documentation, only to find out that a core feature has changed based on new feedback from a key stakeholder. As a result, previously valid test cases may now have outdated behaviours, creating chaos in test results.

Tight deadlines

While the shift-left approach gives QA specialists more time for designing thorough and well-considered test cases, such an approach is not always the reality. Quite often, testing is treated as a phase that comes towards the end of the development cycle. Skipping some details in the attempt to finish work on time might indeed save some time in the short term. This delay often leaves testers in a tough spot, racing against the clock, trying to create meaningful test coverage with limited time, resources, and incomplete information.

When deadlines loom, there’s a natural temptation to cut corners. Testers might skip edge cases, reuse outdated templates without proper customization, or forego peer reviews. While this can help meet short-term delivery goals, the long-term consequences can be severe. Missed bugs—especially those hidden in non-obvious user flows or uncommon scenarios—can escape into production, where fixing them becomes significantly more expensive and time-consuming. Worse, these defects can degrade user experience or even cause compliance issues, depending on the product domain.

Complex business logic and a domain knowledge gap

Some products include more complex workflows, and their logic doesn't always lie on the surface. Without a deeper dive into understanding the logic behind a product or application, the tester might inevitably miss some crucial user journeys or misunderstand the whole functionality. This is especially critical in highly regulated industries (like banking or healthcare) where being precise is the most important.

To overcome this challenge, testers require a significant amount of time to find access to correct resources, look through enormous amounts of documentation, get in touch with people who might be able to answer all their questions, and address unclear pieces of information. All these issues highlight the need to invest time and resources that very often QA specialists don't possess.

Lack of access to test data and test environment

Even the most-tailored, well-designed test cases can fall apart without access to the relevant test data. Having access to the realistic test data is crucial and yet often not possible to obtain due to laws and other regulations. Similarly, access to a production-like experience is not always available,  blocking testers from testing specific features or functionalities. 

In such situations, test cases might need to be refactored or even abandoned simply because their execution is not possible due to the test data not being present or the environment missing a configuration. 

Collaboration challenges

Designing test cases is not a solo journey. This process requires inputs from different stakeholders like product owners, developers, and business analysts. Lack of communication can lead to the creation of knowledge gaps or to situations when assumptions replace facts. As a result, test cases do not reflect actual product requirements. The reasons for collaboration challenges may vary, but all in all, without a common understanding and constant communication, the created test cases could be very far from the actual designed behavior.

You may be interested: Collaboration Between Software Developers and QA Engineers.

Common mistakes in test case design

Getting acquainted with the challenges that the tester might face during test case design is only one part of the equation. Recognising mistakes and being equipped with the knowledge on how to avoid them is a whole new story. No matter how experienced or skilled a QA tester is, we are all sometimes falling into these traps.

1. Unclear objectives 

Each test case needs to have its purpose and answer the questions: what are we verifying, and most importantly, why? Test cases without a clear purpose can create several additional issues, like a lack of focus, unnecessary time spent on testing unrelated functionalities, testing too many outcomes at once, or skipping core flows altogether.

Lack of clarity makes it quite challenging to design new test cases as well as to understand and maintain the existing ones.

2. Incomplete test coverage

One of the most common mistakes, if not the most common one, is inadequate test coverage. Designing test cases only for the “happy path” and not covering negative scenarios and alternative workflows can lead to missing some critical bugs. Sometimes, ensuring that functionality doesn't work when it shouldn't is as important or even more important than ensuring that everything works as expected.

Inadequate test coverage could be a result of a lack of time, complexity of the product, or simply due to inexperienced testers who are yet to learn about equivalence partitioning, boundary value analysis, and other testing techniques.

3. No traceability to requirements

When test cases are not linked to user stories or test scenarios, the task of assessing testing coverage becomes hard to complete: how can you, as a tester, conclude what scope was not yet covered by your test unit if there is no understanding of what was already included? 

Lack of traceability might become a real issue during regression testing: if some feature or part of functionality is deprecated or affected by change, your team will not be able to identify which test cases got affected.

4. Test case duplication

Redundant work is frustrating and inefficient. Duplication isn't only about reusing several steps - it is essentially testing the same scope without even realising this. This mistake might occur when:

• Team members don't check for existing test cases before creating new ones.
• The test suite grew large over time, and it got difficult to maintain and keep track of all the changes made.
• The work on the creation of the new test suite was split between several people, with minimal collaboration.

The problem with the duplicated test cases is that they bring with them a lot of unnecessary headaches: the cost of maintenance rises, the number of test cases creates an illusion of comprehensive test coverage, and testing metrics are becoming less accurate than we would like them to be.

5. Poorly defined expected results

Plain and simple, expected results for any product/feature/functionality could be defined as “We would like it to work as we designed it”. But when the time comes to actual testing, this won't be sufficient. Without a clear definition of expected results, how would you understand if the test passed or failed?

Expected results have to be:

• Measurable - they should have quantifiable conditions or outputs.
• Specific - vague phrasing, such as “opens as designed”, should be avoided.

For example, such expected results as “Verify that feature X works correctly” will not bring a tester any value and, perhaps, will require hours of research and communication with several stakeholders to define what “correctly” stands for. 

6. Underestimating the value of peer review

Just like engineers are benefiting from peer review of their code, testers can benefit from the review of their test cases by their teammates. Establishing peer reviews often highlights blind spots, a mismatch between requirements and the test suite, and unclear steps. Additionally, peer review is a powerful instrument serving as a knowledge-sharing mechanism between experienced and junior-level specialists.

7. No reusability

Not every test case (or even test suite) needs to be a standalone script. It is not an uncommon situation when some workflows and product features have similarities within the same product. And yet, testers are tasked with designing nearly identical start-to-finish test cases over and over again. Let’s say you need to design test cases for the same feature but with different access (guest, user, admin). No matter what access users have, they will have some common steps (entering the same page, testing access to the same functionality, etc). Identifying common elements early and reusing them for several test cases can not only reduce the time spent on test case creation but also strengthen your documentation.

8. Overcomplicating test cases

Missing or not fully comprehending crucial details of the workflows and later on passing these uncertainties into test cases is one side of the coin. On the other side, we have an opposite situation when test cases have way too many details, and attempt to test several aspects of the feature at once. Overcomplicating test cases introduces several complications for testers’ daily life: those test cases are hard to understand, even harder to maintain, they might misguide testers from the critical details, and running a test based on those test cases sometimes requires too much effort (and brings too little value).

A rule of thumb is to keep in test cases just enough details for another fellow tester to be able to understand the test case and test the feature independently. And it is always better to stick to having a separate test case for every critical aspect of the feature instead of squeezing all the expected behaviors into one test case.

9. Ignoring test case maintenance 

Like your favourite old bike or your work computer, test cases require maintenance. Functionalities change, features evolve, workflows adapt to users’ wants and needs, and it is a given. Ignoring those changes and, together with them, maintaining test cases will lead to test cases becoming redundant in the blink of an eye.

Working with test cases is not a one-time task. It is an ongoing process that requires testers to keep their hand on the pulse, be on the lookout for upcoming changes, and be ready to adjust test suites for the project's needs.

You may be interested: Test Case vs. Test Scenario: What’s the Difference?

How to avoid test case pitfalls: Best practices

Navigating the test case design process and trying to avoid all the potential challenges might not look easy, but there are a couple of tricks that can support QA specialists.

Adjust the level of details to meet testing needs

Not all test cases require the same amount of detail. For instance, smoke testing or sanity testing can be efficiently performed using high-level test cases that will give testers general guidance; in contrast, regression testing will require more detailed, low-level test cases to ensure comprehensive test coverage. Aligning the level of detail with the corresponding testing purpose - and agreeing on this with the stakeholders - helps testers avoid additional work when it is not needed.

Use test case management tools

Test case management tools streamline the process of designing, organizing, tracking, and maintaining test cases. Choosing the test case management tool that aligns with your testing needs and requirements might enhance your testing effectiveness and efficiency.

You may be interested: Best 10 Test Management Tools: Free & Paid Options.

Balance out test cases with preconditions

Bulky test cases can be avoided by utilising preconditions. If certain steps must be completed before testing a specific feature or a part of it, it would be a good practice to move these steps to preconditions instead of keeping them within the test case main body. This approach makes test cases more concise, easier to read and understand, and focused on their core testing objective.

Final thoughts

At first glance, designing test cases might look like a very plain and simple, straightforward task. But don't be fooled: this is full of nuances and pitfalls. Challenges like constantly changing product requirements, tight deadlines, complex business logic of the products, or lack of information due to communication issues can make test case design quite an uneasy job to complete.

On top of that, all the common mistakes like incomplete test coverage, poorly defined expected results, or no traceability to the requirements can creep in without you realising it, especially in the absence of enough time to deep dive into the new feature. Mistakes happen. Even heavily experienced QA testers design test cases that won't necessarily meet all the golden standards.

The key is to keep learning from the mistakes and be ready to refine your approach for every new project you join. Perfect test cases don't exist. However, keeping a good level of quality is possible. It will not come from following some sort of checklist, though, but continuous improvement, practice, and attention to detail should do the trick. Being aware of the most common challenges and mistakes already gives a big heads-up. And the more test cases you design (and refactor), the better you’ll become at identifying the problems before they become too costly for your team.

Ready to level up your test design game, avoid costly mistakes, and build QA processes that actually support your team’s success? Get in touch with us to learn more about our QA management services and how we can help you strengthen your test case strategy today.