How to Write Test Cases: Types, Benefits, and Template

Writing test cases is an art and science designed to verify that your application operates as expected. As a test case writer, you write test cases so that testers know how to determine whether a feature of an application or software system is correctly working. Applications must be tested thoroughly to ensure you understand how it behaves under all possible input conditions. 

A clear understanding of software functions and a good knowledge of the test case process make writing test cases that uncover defects and verify functionality easier. Read on to discover how to write test cases and some established formats and templates.

What exactly is a test case?

Test case design begins with application requirements and specifications. The test case designer determines the conditions to test a specific feature or functionality and whether it works. Test cases serve as blueprints and steps for testers to ensure programs function correctly. Test cases describe how the software should work in normal, abnormal, or error operating conditions.

Test case writing converts user requirements into precise test conditions and descriptions describing the system’s functional behaviour. Test cases serve as blueprints and steps for testers to ensure programs function correctly.  Multiple test cases can combine in an automated test script to form a test suite.

Test case vs test scenario 

When writing a test case, you typically think about every detail of 'how' something should behave. For example, if you’re developing a login system, a test case might be that an error is displayed if you enter an incorrect email address. Then you may have tests for:

• Not entering any email address

• Adding a space at the end of an email address

• Use all caps for the email address

• Capitalising the first letter of the email address

Test scenarios, also called test conditions or test possibilities, represent typical tasks users might want to accomplish with the software. A simple test scenario may require multiple test cases to cover the different outcomes. In our login system, some scenarios could be 'I can successfully log in' or 'I can't log in without entering my email address correctly'.

Sometimes, the term test case and test scenario seem interchangeable—but it's helpful to remember that 'scenario' refers to the bigger picture of what you're trying to accomplish with your tests, and a 'test case' focuses on the minute details of the test scenario. 

Different types of test cases 

Test cases can be categorised based on the purpose they serve in testing. As a quality assurance professional, knowing their differences helps focus your efforts and choose the correct test format. 

• Functionality test cases: These are the most basic and obvious test cases to write. They ensure that each feature of your system works correctly. 

• Performance test case: This test ensures the system runs fast enough. It ensures that all system requirements, including speed, scalability, or stability, work as expected. 

• Unit test cases: Software developers usually write unit tests for their code to check individual units, for example, modules, procedures, or functions, to determine if they work as expected. 

• User interface (UI) test cases: It’s important to remember that the user interface is part of the overall system and not just a shell where functionality appears. UI test cases check that each UI element works correctly, displays, and is easy to use. 

• Security test cases: Security test cases help ensure that a product or system functions properly under all conditions, including when malicious users attempt to gain unauthorised access or damage the system. These test cases safeguard the security, privacy, and confidentiality of data.

• Integration test cases ensure that the application components work together as expected. These test cases check whether modules or components integrate seamlessly to form a complete product.

• Database test cases: These cases ensure the database meets its functional and non-functional requirements. They make sure database management systems (DBMS) support all business requirements.

• Usability test cases: Usability test cases help check if users can use the application successfully. These determine whether users can easily use the system without difficulty or confusion. They also verify if users can navigate the system using common procedures and functions.

• User acceptance test cases: User acceptance test cases verify that an application satisfies its business requirements before users accept it. These determine whether users accept or reject the output produced by a particular system before release to the live environment.

• Regression testing: Regression test cases verify that changes made during development don’t cause any existing functionality to stop working. Regression testing happens after changes have been made to the existing code to test that all existing or legacy functionality continues to work as expected after the changes.

Who gets involved in writing test cases? 

Writing test cases is usually the responsibility of someone on the software development, testing, or quality assurance teams. You could also take on the team's specific role as a test case writer. It’s typically preferred that a professional who wasn’t involved with writing the code should write the test cases since they offer a fresh perspective. Agile and Scrum approaches blur the lines between developer and QA, with developers being more involved in testing.

Benefits of writing high-quality test cases

Writing test cases allows you to think through every aspect of your software and makes it easier to identify any software gaps as it develops. Several benefits emerge when you write formal test cases.

• Documentation means you can guarantee the coverage of your tests

• You can reduce software maintenance and bug fixes and support future costs 

• Test cases can be used again in current and future projects

• You can improve the quality of the software and the user experience

• A higher quality product means more satisfied customers and higher profits

General test case template format

A test case template organises and outlines test details, making it easier to go back and review the test. Having a document with all tests as a guide for future review is a good idea. Many testers use spreadsheets with one test per row and the test elements in columns.

The template below is a simple format that’s adjustable for your needs.

• Test Case ID

• Test Case Description

• Pre-Conditions

• Test Steps

• Test Data

• Expected Result

• Post Conditions

• Actual Result

• Status

Best practices and a step-by-step process for writing test cases

Test cases are essentially the 'recipe' for testing, so they must be clear, thorough, and accurate. If you're writing a new test case or revising an existing one, here are some step-by-step processes and best practices for writing test cases.

1. Define the area you want to cover from the test scenario 

2. Ensure the test case is easy for testers to understand and execute 

3. Understand and apply relevant test designs

4. Use a unique test case ID

5. Create test cases with the end user's perspective in mind

6. Use the requirements traceability matrix in testing for visibility 

7. Have a clear description of each test

8. Add proper preconditions and postconditions 

9. Specify the exact expected result 

10. Make test cases reusable and maintainable where possible 

11. Utilise suitable testing techniques 

12. Get your test plan peer-reviewed before moving forwards

Popular test case management tools

Test case management tools help you manage software and hardware development. These tools track your test cases, bugs, and other important information related to testing. 

Countless test case management tools are available in the market. If you’re applying for test case writer jobs or a similar role, you might need prior experience with one or more of these tools: 

• JIRA

• JunoOne

• Klaros-Testmanagement

• QACoverage

• Qase

• SPIRATEST by Inflectra

• TestFLO for JIRA

• Testpad

• XQual

• Xray

• Zephyr Scale

• Zephyr Squad

Jobs in quality assurance and testing

Various roles in software and quality assurance interface directly with the testing process. The following are some of the jobs in which you might write test cases: 

*All annual salary data for India is sourced from Glassdoor as of March 2024. 

• QA engineer: ₹7,20,000 

• Senior software test engineer: ₹17,21,454

• Quality improvement manager: ₹19,43,142

• Senior QA tester:  ₹15,19,035

• Software tester:  ₹1,04,335

• Lead test engineer: ₹14,00,000

• Test analyst: ₹7,69,707

• Game tester: ₹15,90,285

Requirements to work in quality assurance and testing

Training, knowledge, and skills are necessary to write test cases successfully. These include the following:

• Business or IT degree: Many professionals who write test cases have a business or IT-focused degree. To write test cases, you must understand the business and technology sides. Some QA professionals have a degree in data science. A few schools offer majors in quality assurance.

• Understanding the software development life cycle and code: A clear understanding of the software development lifecycle will be helpful. You may also benefit from a knowledge of code to understand common reasons for bugs.

• Business analysis skills: Business analysis skills are highly relevant in QA because they help you determine the most important features, what to test first, and how tests work together. You'll also use these skills when creating test cases and documentation for stakeholders who don't have a technical background.

• Writing skills: Writing skills are essential for communicating clearly with customers, testers, and other team members. QA testing requires frequent communication between all parties involved, so writing is essential. 

• Attention to detail: Attention is crucial for QA because you must be able to break down software and identify all test cases and test scenarios, no matter how small a case may seem at first glance. 

• A good understanding of the application under test (AUT): You'll need to thoroughly understand the software you’re testing. This will help you identify potential bugs and issues with the application and suggest enhancements and improvements.

Next steps

If you want to gain more experience with quality assurance or testing, consider taking a course. For a good overview of the interface between development and operations, consider the Introduction to DevOps course offered by IBM on Coursera. In addition, you'll also discover best practices for building a good software development culture, resilient code, test-driven development, and more.