Test Case Design Techniques in Software Testing

Test case design techniques are the key to planning, designing, and implementing tests for software applications. These techniques involve various steps that aim to ensure the effectiveness of test cases in uncovering bugs or other defects in software programs. This blog post will review all these techniques, including their pros and cons and when to use them.

Test Case Design Techniques

There are tons of different ways to design your test cases. These techniques help you test all your software’s features and functions efficiently.

Let’s take an example to understand this concept better.

A basic example of test case design

Let us take an example of any e-commerce app or website(like Amazon or Flipkart)for test case design. We want to ensure users can quickly checkout and make payments without issues. Here we test for 1 product in the cart; we will see later that this test case design technique is a boundary value analysis technique.

Title: Test that user can complete the checkout process when there is 1 item in the card.

Description: Ensure users can checkout and make payments without issues on the website/app

Preconditions: The user is already logged in

Assumptions: They are using a supported device or browser to log in.

Test Steps:

1. Open the app/website.
2. Go to 1 product
3. Add the product to the cart.
4. Check out the item in the cart.
5. Add address information for delivery
6. Add payment information
7. Complete the checkout process.

Expected Result: The checkout process should be complete, and the user should receive confirmation.

What are the types of test case design techniques?

These test case design techniques can be classified into three major groups: :

• Specification-based
• Structure-based
• Experience-based

Specification-Based or Black-Box techniques

Specification-based testing, also known as black-box testing, is a testing technique that focuses on testing the software system based on its functional requirements and specifications without any knowledge about the underlying code or system structure.

1. Boundary Value Analysis (BVA) identifies errors at the input domain’s boundary. A simple example of boundary value analysis would be testing a text box that requires the user to enter a number between 1 and 10. In this case, the boundary values would be 1 and 10, and we would test with values that are just above, at, and just below these boundaries.
   
   For example, we would test with 0, 1, 2, 9, 10, and 11. We can expect that errors or defects are most likely to occur at or near the boundary values. Identifying these issues early can help prevent them from causing problems later in the software development process.


2. Equivalence Partitioning (EP) is another technique that helps reduce the required test cases. By partitioning test input data into classes with an equivalent number of data, one can design test cases for each class or partition. This technique ensures that one thoroughly tests the software while minimizing the required test cases.
   
   For example, if a program requires an input of numbers between 1 and 100, an EP test would include a range of values, such as 1-50 and 51-100, and numbers outside that range, such as -1 or 101. Testing one value from each partition is sufficient to test all values within that partition.


3. Decision Table Testing is a technique that involves designing test cases based on decision tables formulated using different combinations of inputs and their corresponding outputs based on various conditions and scenarios sticking to other business rules. This technique ensures that we test the software thoroughly and accurately.
   
   For example, if a program offers discounts based on the type of customer and the amount spent, a decision table would list all possible combinations of customer types and the amount paid to receive a discount. Each cell in the table would specify the value that should be applied. Testers can ensure the program behaves correctly under various scenarios by testing all combinations.


4. Developers use State Transition Diagrams(STD) to test software with a finite number of states of different types. A set of rules that define the response to various inputs guides the transition from one state to another. This technique is handy for systems with specific workflows within them.
   
   For example, consider an e-commerce website that has different states such as “logged out,” “logged in,” “cart empty,” “cart not empty,” and “order placed.” The transitions between the states would be triggered by login in and logout, adding the product to the cart, removing the product from the cart, proceeding to checkout, etc. An STD can help visualize and test such complex states and transitions in a system.


5. Use Case Testing involves designing test cases to execute different business scenarios and end-user functionalities.
   
   For example, A use case could be a “student enrolling in a course” on an academic website. Test cases would simulate the enrollment process and verify the system’s response from a student’s perspective.

Structure-Based or White-Box techniques

Structure-based testing, also known as white-box testing, is a testing technique that involves the testing of internal structures or components of software applications. In this approach, the tests interact with the code directly. These tests are designed to ensure the code works correctly and efficiently.

1. Statement Testing and Coverage is a technique that involves executing all the executable statements in the source code at least once. We then calculate the percentage of executable statements as per the given requirement.
   
   For example, consider code that inputs two numbers and checks if the first number is greater than or equal to the second. A statement coverage test would verify that both the “greater than” and “equal to” statements are executed during testing to ensure that all code branches are covered.


2. Decision Testing Coverage, also known as branch coverage, validates all the branches in the code by executing each possible branch from each decision point at least once. This helps ensure that no branch leads to unexpected application behavior.
   
   For example, if a program requires an input of a number between 1 and 100 and uses an “if/else” statement to check if the number is even, decision testing coverage would ensure that both the even and odd outcomes have been tested to confirm all possible scenarios have been checked.


3. Condition Testing, also known as Predicate coverage testing. It involves evaluating each Boolean expression in the code and checking its output values, TRUE or FALSE, against the expected outcomes. This test checks all outcomes at least once to achieve 100% code coverage. We design test cases that make it easy to execute the condition outcomes.
   
   For example, if a program determines whether a user is eligible for a discount based on age, condition testing would verify that the code handles each age group accurately. It would test age values such as one less than, one more than, and within the age range requirement to evaluate if the code performs as expected.


4. Multiple Condition Testing aims to test different combinations of conditions to achieve 100% coverage. This technique requires two or more test scripts, which may require more effort.
   
   For example, if a program uses an “if/else” statement to check age and gender to provide a discount, multiple condition testing would verify that the program handles all possible scenarios correctly. It would test various age ranges and gender combinations to ensure the code performs accurately for all possibilities.


5. All Path Testing leverages the source code of a program to find every executable path.
   
   For example, if a program asks a user for two inputs (A and B) and has multiple conditions, All Path Testing would ensure that each condition is tested independently. The technique would test all combinations of A and B, including zero, negative, and positive Testings, to identify any potential errors in the code.

By implementing these testing techniques, testers, and developers can ensure the Testing code is thoroughly tested and free of unexpected behavior. Choosing the appropriate method based on the project’s specific requirements is essential.

Experience-Based techniques

The experience-based techniques can be broadly categorized into the following types:

• Error Guessing is a testing technique that relies on the testers’ skill, intuition, and experience to anticipate potential errors in the product.


• On the other hand, Exploratory Testing is a technique used to test applications without any formal documentation. This method is recommended once scripted testing has been executed when working on the software.

Test Case Software for managing Test Cases

To ensure accurate test case management, it is essential to utilize refined test case software. This tool helps craft detailed test cases and enables users to report bugs that may arise from any failed step quickly.

Its advanced features allow for creating complete reports through built-in filters, providing valuable insights that can be acted upon. This innovative software empowers teams to manage their testing processes and deliver high-quality results efficiently.

Examples of these tools include:

1. TestRail: A web-based tool that helps to manage, track, and organize test cases.

1. Zephyr: A comprehensive test case management tool that integrates with Jira and offers real-time visibility into testing activity.

1. TestLink: An open-source test management tool that handles multiple test plans, requirements, test cases, and test reports.

1. SpiraTest: A flexible and comprehensive test management platform that offers traceability, version control, and defect tracking.

1. qTest: A web-based test management tool that automates test scheduling, offers collaboration, and integrates with other testing tools.

Can these designs be helpful while automating your tests?

Yes! Test case design techniques help to create a structured approach to test automation. When test cases are well designed, achieving better test automation results is easier, sooner.

Testsigma is a no-code test automation tool that enables teams to create test cases in simple English. With that, it also supports data-driven testing and enables testers to implement all the test case designs efficiently.

Read more about data-driven testing with Testsigma here: https://testsigma.com/data-driven-testing

Testsigma is also available as open source and free version.

Start automating your test cases, in minutes, with Testsigma Open Source

Summary

In this blog, we learned about test case design techniques that are fundamental in ensuring the effectiveness and efficiency of software testing. Knowledge of these Testing techniques can enhance the testers’ ability to design smart test cases that will be able to identify potential defects, avoid common pitfalls, and assess the performance and functionality of different software systems, better.

Frequently Asked Questions

Why are test case design techniques used?

These techniques are employed to optimize the testing process by identifying critical Testing and reducing redundancy, thus allowing for the efficient allocation of resources.

What are the advantages of test case design techniques?

1. Test case design techniques provide a more structured approach to testing, resulting in comprehensive test coverage and higher-quality software.
2. Using these techniques, testers can identify complex scenarios, generate effective test data, and design test cases that evaluate full system functionality.
3. It helps reduce the risk of missed defects and ensures all software requirements are met.
4. These techniques support faster and more efficient testing, reducing costs and increasing software reliability.