Test Case Design Techniques with Examples

Introduction

Testing is the most significant phase in the software development process. Not only does QA testing help to determine the product quality but it also helps in modifying the product in terms of end-user usability and friendliness. In this article, we will address the fundamental notion of test case design techniques and their types. 

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But before we deep dive into the test designing techniques with examples first, begin with the test design definition and techniques.

Test Design Definition and Technique

Test design is a process that describes “how” testing should be done. It includes processes for identifying test cases by enumerating steps of the defined test conditions.

• Test design is the act of creating and writing test suites for testing software.
• Test analysis and identifying test conditions give us a general idea for testing which covers quite a large range of possibilities. But when we come to make a test case, we need to be very specific. In fact, now we need the exact and detailed specific input. But just having some values to input to the system is not a test, if you don’t know what the system is supposed to do with the inputs, you will not be able to tell whether your test has passed or failed.

Test Design Technique

Software Testing Techniques help you design better test cases. There are many different types of software testing technique, each with its own strengths and weaknesses. Each individual technique is good at finding particular types of defect and relatively poor at finding other types.

For example, since exhaustive testing is not possible; registering yourself to the QA Certification Course will help reduce the number of test cases to be executed while increasing test coverage. They help identify test conditions that are otherwise difficult to recognize.

Broadly speaking there are two main categories of Test Design Techniques. They are:

1. Static Techniques
2. Dynamic Techniques

We will be broadly discussing DYNAMIC testing techniques. There are 5 important software testing techniques: 

• Boundary Value Analysis (BVA)
• Equivalence Class Partitioning
• Decision Table based testing.
• State Transition
• Error Guessing

Static Testing Techniques: Definition and Benefits

Static testing is a type among different software testing techniques that are performed to identify the errors in software without executing the code. This type of testing is generally performed at the initial stage of software development to avoid defects as it is easier to figure out the sources of failures and can be fixed quickly.  

Static Review

Static testing review is a technique, performed to identify the defects in software design. Under this process, errors are detected and defeated in different supporting docs. 

There are four types of review: 

• Informal – The document creator put the contents in front of the audience and lets people give their opinion. 
• Walkthrough – Performed by experienced professionals to identify the defects if there is any possibility of problems. 
• Peer Review – Checking documents to detect and fix the errors. 
• Inspection – The verification of the document 

Static Analysis 

The Static Analysis covers the evaluation of the quality of the code written by developers. Different types of tools are utilized in code analysis and comparison of the same within the standard. 

It widely helps to find defects like – Dead code, Unused code, Wrong Syntax, Infinite loops, and variables with undefined values.

There are three types of Static Analysis: 

• Data Flow: This is related to the stream processing
• Control Flow: How the statements are executed. 
• Cyclomatic Complexity: The measurement of the complexity of the program, related to the number of independent paths. 

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Benefits of Static Testing Technique

1. Helps in identifying the flaws in code
2. The testing is conducted by trained software developers with good knowledge of coding
3. It is a fast and easy way to find and fix errors
4. With automated tools, it becomes quite fast to scan and review the software
5. The use of Automated tools provides mitigation recommendations
6. With static testing it is possible to find errors at an early stage of the development life cycle, thus, in turn, reducing the cost of fixing.

Dynamic Testing Techniques: Definition & Benefits

Dynamic testing is a type of software testing, performed to analyze the dynamic behavior of the code. It includes software testing for the input values and output values that are analyzed. Dynamic testing mainly refers to the observation of the physical response from the system. For dynamic testing, the software needs to be compiled and run.

Now, we will be broadly discussing DYNAMIC testing techniques. There are 5 important software testing techniques: 

• Boundary Value Analysis (BVA)
• Equivalence Class Partitioning
• Decision Table-based testing.
• State Transition
• Error Guessing

1.Boundary Value Analysis (BVA)

Boundary value analysis (BVA) is based on testing the boundary values of valid and invalid partitions. It includes maximum, minimum, inside or outside boundaries, typical values and error values.

 The Behavior at the edge of each equivalence partition is more likely to be incorrect than the behaviour within the partition, so boundaries are an area where testing is likely to yield defects. It is also known as BVA and gives a selection of test cases which exercise bounding values.

This comes under the black-box testing technique. Thus, if a system works well for these particular values then it will work perfectly well for all values which come between the two boundary values.

Guidelines for Boundary Value analysis

• If an input condition is restricted between values x and y, then the test cases should be designed with values x and y as well as values which are above and below x and y.
• If an input condition is a large number of values, the test case should be developed which need to exercise the minimum and maximum numbers. Here, values above and below the minimum and maximum values are also tested.

Example:

Input condition is valid between 1 to 10

Boundary values 0,1,2 and 9,10,11

2. Equivalence Class Partitioning

In this method, the input domain data is divided into different equivalence data classes. This method is typically used to reduce the total number of test cases to a finite set of testable test cases, still covering maximum requirements.

The concept behind this technique is that the test case of a representative value of each class is equal to a test of any other value of the same class. It allows you to Identify valid as well as invalid equivalence classes.

Example:

Input conditions are valid between

 1 to 10 and 20 to 30
Hence there are five equivalence classes

--- to 0 (invalid)
1 to 10 (valid)
11 to 19 (invalid)
20 to 30 (valid)
31 to --- (invalid)
You select values from each class, i.e.,
-2, 3, 15, 25, 45

3. Decision Table Based Testing.

A decision table is a good way to deal with different combination inputs with their associated outputs. It is a black box test design technique to determine the test scenarios for complex business logic.

It is also known as to Cause-Effect table because of an associated logical diagramming technique called cause-effect graphing that is used to derive the decision table. This software testing technique is used for testing the system behaviour for different input combinations.

The first task is to identify functionalities where the output depends on a combination of inputs. If there are large input set of combinations, then divide it into smaller subsets which are helpful for managing a decision table.

For every function, you need to create a table and list down all types of combinations of inputs and its respective outputs. This helps to identify a condition that is overlooked by the tester.

Example: The condition states that if the user provides the correct username and password the user will be redirected to the homepage. If any of the input is wrong, an error message will be displayed.

Conditions	Rule 1	Rule 2	Rule 3	Rule 4
Username	F	T	F	T
Password	F	F	T	T
Output	E	E	E	H

In the above example,

• T – Correct username/password
• F – Wrong username/password
• E – Error message is displayed
• H – Home screen is displayed

4. State Transition

State Transition Testing is a black-box testing technique that is carried out to observe the behaviour of the system or application for different input conditions passed in a sequence. In this type of testing, both positive and negative input values are provided and the behaviour of the system is observed. In-State transition technique, the testing team provides positive as well as negative input test values for evaluating the system behaviour.

Example:

In the following example, if the user enters a valid password in any of the first three attempts the user will be able to log in successfully. If the user enters the invalid password in the first or second try, the user will be prompted to re-enter the password. When the user enters password incorrectly 3rd time, the action has taken, and the account will be blocked.

State transition diagram

In this diagram when the user gives the correct PIN number, he or she is moved to Access granted state. 

In the above, when the user enters the correct PIN, the state is transitioned to Access granted. And if the user enters an incorrect password, he or she is moved to the next state. If he does the same 3rd time, he will reach the account blocked state.

5. Error Guessing

Error guessing is a software testing technique that depends on speculating the mistake which can win in the code. It is an encounter-based system where the test expert uses his/her experience to figure out the problematic piece of the testing application.

The technique counts a list of possible errors or error-prone situations. At that point, the tester composes an experiment to expose those errors. To design test cases or test case design strategies based on this software testing technique, the analyst can use past experiences to identify the conditions.

Test Design Tools

Test design tools help to run test cases, or if nothing else test inputs (which is a piece of a test case). 

For example, if the requirements are kept in a test management tool or a Computer-Aided Software Engineering (CASE) tool used by developers, then it is possible to identify the input fields, including the range of valid values. This range of information can be used to make out boundary values and equivalence partitions. If the valid range is stored, the tool can distinguish between values that should be accepted and those that should not be accepted and generates an error message. If the error messages are stored, and then the expected result can be checked in detail. If the expected result of the input of a valid value is known, then that expected result can also be included in the test case constructed by the test design tool.

Benefits of Dynamic Testing Technique

• Dynamic testing could identify the weak areas in the runtime environment.
• Dynamic testing supports application analysis even if the tester does not have an actual code.
• Dynamic testing could identify some vulnerabilities that are difficult to find by static testing.
• Dynamic testing also could verify the correctness of static testing results.
• Dynamic testing could be applied to any application.

Now, let’s go through the different test case design examples to understand them better. 

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Conclusion on Software Testing Techniques

In the bottom line, QA testing is vital, it takes the form of business requirement reviews, design reviews, functional reviews, test documentation reviews, design reviews, and code walkthroughs. While the dynamic testing part is more hands-on; it generally happens on the product itself and not on a representation or artifact of the product. A much formal process of test case/condition identification, execution, coverage considerations, and defect reporting all represent the dynamic testing techniques. This is how dynamic and static testing is different…

Hopefully, you found the blog helpful in understanding the basics of dynamic and static testing, their testing techniques, and how they are different and test design techniques with examples. Software testing has entered as a good career option with lucrative QA testing salary packages. If you are willing to enter a software testing career, it's recommended to opt professional QA testing training course and start your QA journey for a successful career. If you want to explore more about the QA testing career path and respective training feel free to reach us.

 If you have any doubts or questions, feel free to comment below. 

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FAQs on Software Testing Techniques

Q1) . What are the types of test case design techniques?

Ans:- Here are a few types of testing techniques:

• Functionality test cases
• User interface test cases
• Security test cases
• Performance test cases
• Database test cases
• Usability test cases
• Unit test cases
• Integration test cases

Q2) . What is test case design in software testing?

Ans:- The test case design is referred setting up your test cases. Designing your tests correctly is important or you could fail in finding bugs in your software during testing.

Q3). What is test design techniques? 

Ans:- The test case design technique helps to organize test data into groups, ensuring each member generates the same results. In case, one test of the group fails, all the others also fail. Hope you got your answers for what is test design techniques.

Q4) . What are the latest trends in software testing techniques? 

Ans:- Here are some of the best test design trends which need to be followed in 2022.

• Blockchain
• Big Data
• Performance Engineering
• Cybersecurity
• IaC
• Chatbots
• Test Automation in Agile Model
• Machine Learning and Artificial Intelligence Test Automation

Q5). Is the QA career path profitable today?

Ans:- A career in software testing techniques is well-paid and comes up with great career opportunities.  In addition, the training is affordable and accessible at any time. If you are still not sure, check the QA Career Path. 

Q6) . What is a QA tester's Salary? 

Ans:- The average salary of a QA tester is $28.75 per hour in the United States and a $2,700 cash bonus per year. 694 salaries reported, updated on February 22, 2022. Check more insights on QA tester Salary.

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