Test Case Design In Software Engineering

The secret to organizing, creating, and executing software application tests is test case design techniques. These methods entail a number of procedures designed to guarantee that test cases are successful in identifying errors or other flaws in software applications. In this blog post, we will be covering test case design techniques together with their advantages and disadvantages and when to use them.

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What Is Test Case Design?

In the test design stage, test cases and scenarios that may be executed on the application under test (AUT) are created. The completed test cases from the test design phase are carried out in the test execution step. It’s fair to say that the cornerstone of software testing is test cases. In order to stop defects from propagating to higher levels, they must be well-designed, easy to understand, and, most importantly, provide 100% functional coverage. In this situation, the methods for test case design offer a methodical way to produce test cases. Randomly generated test case suites are not covered or of high quality, which leads to bug leaks.

Importance Of Test Case Design

• keeps the software in good condition.
• Increase the coverage of tests.
• conserves time and energy.
• Encourages Teamwork.

When to Create a Test Case Design?

Timing is crucial while developing a test design. Waiting until the last minute puts you at danger of making mistakes that could affect the outcome of your tests. However, you can find yourself making adjustments that render your findings invalid if you begin too early.

Finding a middle ground between these two extremes is essential. Ideally, you should start designing your test cases as soon as the testing conditions are established and you have sufficient data to develop the test strategy.

You’ll have plenty of time to make the required changes and make sure your test case design is solid and dependable.

How to Write a Great Test Plan?

A test plan is an unavoidable part of any software development project. It helps in establishing the success criteria, defining the testing process’s scope, and determining which areas require testing. To write a great test plan, you must consider a few important factors.

You must first comprehend the program needs completely. What precisely must the software accomplish? Which user stories are in need of testing? You can begin creating your test cases as soon as you have a solid grasp of the requirements.

An exact series of actions intended to evaluate a certain software feature is called a test case design. You should be able to tell whether the program is working as planned by looking at the expected outcome of each test case.

Lastly, you must set exit criteria for your testing procedure. By doing this, you may ascertain when the software is prepared for public release. These easy steps will help you create a fantastic test strategy that will assist guarantee the success of your project.

 Types Of Test Case Design Techniques

Test case design techniques can be categorised into three major groups:

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

Specification based Or Black box Techniques

Black-box testing, sometimes referred to as specification-based testing, is a testing methodology that concentrates on evaluating the software system according to its functional requirements and specifications without having any knowledge of the system structure or underlying code.

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Boundary Value Analysis (BVA)

Detects mistakes near the edge of the input domain. Testing a text box that asks the user to enter a number between 1 and 10 is a straightforward embodiment of boundary value analysis. The values we would test with in this scenario would be slightly above, at, and below the boundary values, which would be 1 and 10.

To test, for instance, 0, 1, 2, 9, 10, and 11. The likelihood of mistakes or faults occurring at or close to the boundary values is something we can anticipate. Detecting these flaws early on in the software development process can help keep them from becoming problems later on.

Equivalence Partitioning (EP)

is another method that aids in lowering the number of test cases needed. It is possible to create test cases for every class or partition by dividing test input data into classes with a comparable amount of data. This approach minimizes the number of necessary test cases while guaranteeing comprehensive software testing.

If a program asks for numbers between 1 and 100, for instance, an EP test would contain both numbers outside of that range, like -1 or 101, and a range of values, such 1-50 and 51-100. It is sufficient to test one value from each partition in order to test all of the values inside that partition.

Decision Table Testing

It is a method that entails creating test cases using decision tables that are created using numerous input combinations and the accompanying outputs depending on different scenarios and conditions while adhering to other business principles. This method guarantees that we perform accurate and comprehensive software testing.

A decision table would include all potential combinations of customer kinds and the amount paid in order to obtain a discount, for instance, if a program offers discounts based on the type of customer and the amount spent. The value to be applied would be specified in each table cell. By testing every possible combination, testers can make that the program operates as intended in a variety of situations.

 State Transition Diagrams(STD)

To evaluate programs that have a limited number of distinct states. The transition between states is governed by a set of rules that specify how different inputs should be handled. This method works well for systems that have certain workflows.

Take an e-commerce website, for instance, that has several states, including “logged out,” “logged in,” “cart empty,” “cart not empty,” and “order placed.” Logging in and out, adding a product to the cart, taking it out of the cart, checking out, and other actions would cause the statuses to change. Such intricate states and transitions in a system can be tested and visualized with the use of an STD.

Use Case Testing

It entails creating test cases to carry out various end-user and commercial scenarios.

A “student enrolling in a course” on an academic website, for instance, could be a use case. Test cases would replicate the enrolling procedure and confirm how the system responds from the viewpoint of a student.

Structure Based or White Box techniques

Structure-based testing, sometimes referred to as white-box testing, is a method of assessing software applications’ core structures or components. This method involves direct interaction between the tests and the code. The purpose of these tests is to guarantee that the code operates accurately and effectively.

Statement Testing and Coverage

Using this method, every executable statement in the source code is run at least once. After that, we determine the proportion of executable statements in accordance with the specified criteria.

A statement coverage test would confirm that both the “greater than” and “equal to” statements are performed during testing to guarantee that all code branches are covered, for instance, in code that takes two inputs and determines if the first number is greater than or equal to the second.

Decision Testing Coverage

It is also referred to as branch coverage, it verifies every branch in the code by running every potential branch from every decision point at least once. By doing this, you can make sure that no branch will result in strange application behavior.

In the event that a program asks for a number between 1 and 100 and employs a “if/else” statement to determine whether the number is even, decision testing coverage would guarantee that both the even and odd outcomes have been tested to verify that every scenario has been examined.

Condition Testing

It is sometimes referred to as “predicate coverage testing.” Evaluation of each Boolean expression in the code entails comparing the expected results with the output values, TRUE or FALSE. This test aims for 100% code coverage by verifying every result at least once. Our test cases are designed to facilitate the execution of the condition outcomes.

Condition testing would confirm that the code appropriately handles each age group, for instance, if a program decides whether a user qualifies for a discount depending on age. To see if the code works as intended, it would test age values like one less than, one greater than, and inside the required age range.

Multiple Condition Testing

In order to attain 100% coverage, it attempts to test various combinations of criteria. Two or more test scripts are needed for this method, which could take more work.

If a program checks age and gender using a “if/else” statement to give a discount, for instance, multiple condition testing would confirm that the program handles every circumstance appropriately. It would test different gender combinations and age ranges to make sure the code works correctly in every scenario.

All Path Testing

This method uses a program’s source code to locate all executable paths. All Path Testing would guarantee that every condition is checked separately, for instance, if a program has many conditions and requests two inputs (A and B). The method would find any possible bugs in the code by testing every possible combination of A and B, including zero, negative, and positive tests.

Experience Based techniques

The following categories can be used to broadly classify experience-based techniques:

Guessing Errors

It is a testing method that depends on the ability, judgment, and experience of the testers to foresee possible mistakes in the final result.

Exploratory Testing

It is a method for testing apps that don’t have official documentation. When working on the software, this approach is advised once scripted testing has been completed.

CONCLUSION

Finding every potential input and output for a software system, together with the procedures required to create those inputs and validate the outputs, is the goal of test case design. While there are other methods for designing test cases, state transition diagrams, equivalency class splitting, and boundary value analysis are some of the most popular ones. By using these test case design strategies, you may produce thorough and useful test cases that will assist you in identifying flaws in your software system and releasing bug-free goods to advance your company.

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