Test Case Design Techniques & When to Change Them

QA Testing involves developing test cases using various test design techniques to keep them fresh and actively identifying defects. Test case design and development have a singular purpose in determining if application features satisfy documented and undocumented functionality. The purpose of developing applications for customers is to satisfy a customer’s business or personal needs by providing a secure, accurate, and efficient application that works as expected.

Works, as expected, are three words with a significant impact on test case design. Works, as expected,, means the application function being tested works as a customer expects. Again, the functionality a customer expects should be documented through use case scenarios, requirements, or user story acceptance criteria. Test case design must accurately capture the intent of the application function so features can be tested repeatedly over time to ensure the application performs as intended between code releases or versions.

This blog describes what test case design means, its impact on ensuring software application quality, how to create or choose an effective design, and when to update it.

Key Takeaways:

• What does Test Case design mean?
• Why is Test Case design important to software quality?
• Why is Test Case design part test technique and part design format?
• Find out how to choose Test Case design methods.
• Should the Test Case design always be the same, or when to update the design?
• Learn the value of test case design for finding defects and ensuring quality.

What does Test Case Design mean?

Test case design refers to the format of a test case as well as the test case content. The goal of creating test cases is to identify defects in the software application. A solid test case design strategy enables a QA testing team to provide business value by repeatedly and efficiently identifying defects before customers experience them.

Test case design requires a thoughtful approach to identify missing requirements and defects without wasting resources or time. In other words, a solid test case design strategy creates tests that are useful, concise, and re-usable over the application’s lifetime. Test design techniques influence how test cases are written to provide maximum code coverage. Effective test technique and test case design combined enables QA test teams to create fewer tests that still verify and validate all application functionality.

When developing a test case design strategy, consider using some or all of the following types of test design techniques:

• Specification
• Boundary value analysis
• Equivalence partitioning
• Decision tables
• State transition
• Use case scenarios
• Structure
• Code statement
• Decision statement branches
• Condition code coverage
• Experience
• Error guessing
• Exploratory testing

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In most QA testing teams, using all test design techniques is not realistic. Consider choosing one or two that best suit the development team structure, QA resources, and the software application’s needs.

For example, a test case design strategy for a mobile app that tracks patient lab results and alerts doctors when a lab result is in a negative range must be thoroughly covered.

For more thorough test coverage, use decision tables combined with use case scenarios or user story acceptance criteria and exploratory testing. The combination provides detailed input and output verification while also ensuring all requirements are met. Adding exploratory testing techniques helps to uncover defects caused by missing requirements or design features.

Define the strategy based on what works best for ensuring the application release exceeds customer expectations consistently across releases.

Why is Test Case Design important to Software Quality?

Test case design is important for producing high-quality software applications that satisfy customer needs and create positive user experiences. Effective test case design documents application functionality based on requirements, acceptance criteria, or expected use case scenarios. Exceptional test case design also identifies defects in design or missing requirements. For example, test cases may find a story or feature that requires more work to function properly.

Well-designed test cases also provide application feature documentation that serves as the basis for help documentation or even end-user training or documentation needs.

Other benefits of test case design include:

• Thorough code test coverage
• Reduced maintenance and documentation creation costs
• Software validation for user acceptance
• Improved customer experience
• Reduced customer support tickets for customer defects and inquiries

Why is Test Case Design one part Test Technique and one part Design Format?

An exceptional test case design strategy includes both test techniques and an effective design format. Test case design format refers to how a test case design is structured. Many QA test teams use Test Case Management tools that enable different types of formats.

Common test case design formats include:

• Sequential steps
• User journey stories
• Functional tours
• Feature Checklists

The format impacts the technique used when developing test cases. QA teams frequently use sequential or ordered steps that test a single functional verification point. A series of sequential steps are used to create an end-to-end or system test that verifies the functional workflow of the application.

User journey stories are test cases written in paragraphs that describe how a user steps through a function in the application. The text does not list the exact steps taken in a specific order but rather leaves the steps up to the user. User journey stories are an excellent approach for including positive and negative test scenarios in a single test case.

Functional tours are typically also written in paragraphs that describe the function to be verified. Functional tours can be based on customer workflow scenarios or simply exercise and verify separate functions within an application. Tours are excellent ways to test integration points between applications and dependent systems such as APIs and databases in an indirect fashion that simulates a real user experience.

Feature checklists are test cases formatted in the form of a list. Checklists are quick to write and can ensure all critical points are covered for each application function. One problem with checklists is they don’t provide the detail necessary for user or reference documentation.

When choosing a test case design strategy, including selecting the format(s) combined with the testing technique(s) that work best for ensuring customer satisfaction and exceptional application quality.

When to Update Your Test Case Design

It’s best to review your test case design regularly as part of a continuous improvement effort. Test case design should be updated or changed if test cases are too difficult to follow or are missing defects. For example, if you find that test cases are executed but defects still end up in the customer release, then it’s prudent to review the test case design and format.

Don’t fear changing the test design format. If change is needed, then simply try a different format, and see which format identifies defects more effectively. Quality metrics are handy for this use and may provide real-time feedback on test design effectiveness over time. Changing formats does not mean re-writing every test. Simply use the new format going forward for new test case development.

If the organization is moving towards increasing test automation, then the sequential step format may enable automated scripting more effectively. The designation of each step helps create small, automated test scripts focused on a single verification point. Automated test tools often struggle with complex workflows with undefined steps. Sequential steps or checklists may assist in creating working automated scripts that are easily maintained.

The test case design is important to providing verification and validation of application functionality across an application’s lifecycle. Effective test case design includes selecting test techniques and deciding on a format. Remember when deciding on a test case design, that the purpose is to identify defects and improve the application quality when released to customers. Higher-quality application releases result in positive customer experiences. The happier the customer with the application, the higher the business value of QA testing.

Great test designs help create applications with exceptional customer experience. Use test design to your testing advantage.

Amy E Reichert

Amy E Reichert is a Freelance writer for a variety of topics focused mainly on QA testing, Agile, and technology trends. Amy has 23 years of professional experience as a QA Engineer/Analyst within the ERP, healthcare, and business management sectors. Many years of developing test process, leading diverse and inclusive teams as well as testing on mobile and web applications.

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