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Top 10 Test Design Techniques

A test design technique is a systematic approach to creating test cases based on a specific criterion or set of criteria.

These techniques are used to create effective test cases that are able to identify defects in a software product or system.

Equivalence Partitioning

Equivalence Partitioning is a test design technique that divides the input domain of a system into equivalence classes or partitions, where each partition is expected to exhibit similar behavior or characteristics. It is based on the assumption that if one value in a partition is valid, then all values in the same partition should be valid as well, and if one value in a partition is invalid, then all values in the same partition should be invalid as well.

Equivalence Partitioning is used to reduce the number of test cases needed to achieve full coverage of the input domain by selecting representative test cases that cover each partition.

Boundary Value Analysis (BVA)

Boundary Value Analysis (BVA) is a test design technique used in software testing to identify errors in boundary or edge conditions of software functionality. In BVA, test cases are designed to check the boundary values of input parameters. It is based on the concept that errors are likely to occur at the extremes of the input domain. For example, if a program accepts values from 1 to 100, then boundary values would be 0, 1, 100, and 101. The test cases would be designed to check the behavior of the program when these boundary values are used as input. The purpose of BVA is to detect any errors that might occur at or near the boundaries of the input domain.

Decision Table Testing

Decision Table Testing is a software testing technique used to test the functionality of the software system, especially when it involves complex business rules or logic. It involves creating a table that captures all possible combinations of inputs, and the corresponding actions or outputs. The technique is based on the principle of partitioning the input and output values of the software system into discrete groups or categories. These categories are defined by the input conditions that trigger the software system to perform specific actions or produce specific outputs.

Decision table testing helps to ensure that all possible combinations of inputs and actions are tested and that the software system behaves correctly for all possible scenarios.

It can also help to identify missing or incomplete requirements and to clarify ambiguities in the specification.

State Transition Diagrams

State Transition Diagrams (STD) is a test design technique that is commonly used for testing the behavior of a system. It is a graphical representation of the states and state transitions that a system undergoes during its operation.

The State Transition Diagrams technique is used to identify all possible states of a system, the events that cause a system to transition from one state to another, and the actions that occur when a system makes such a transition. This technique is used for testing systems that have a finite number of states and state transitions.

State Transition Diagrams are also useful for identifying invalid state transitions or non-existent states. By analyzing the State Transition Diagram, testers can determine if the system behaves correctly or not. This technique is often used in the development of user interfaces, as it helps to visualize the different states and transitions of the user interface. It is also used in testing embedded systems, real-time systems, and network protocols.

Use Case Testing

Use Case Testing is a test design technique that involves identifying, analyzing, and testing scenarios that are used by end-users of a system. Use cases are descriptions of the interactions between the user and the system, including the steps that the user takes to accomplish a particular task. In Use Case Testing, the test cases are designed based on use cases. The test cases can be designed in a way to cover different scenarios of user interaction with the system.

This technique is often used in Agile methodologies where the focus is on delivering value to the customer. Use Case Testing ensures that the system meets the needs of the end users and that the features and functionalities of the system are tested in a way that reflects real-world usage.

Pairwise testing

Pairwise testing, also known as all-pairs testing or combinatorial testing, is a test design technique used to test the interactions between pairs of input parameters. It is based on the principle that not all combinations of input values need to be tested to achieve adequate test coverage. Pairwise testing uses mathematical algorithms to identify a reduced set of test cases that cover all possible pairs of parameter values.

This can significantly reduce the number of test cases required while still providing thorough test coverage. Pairwise testing is especially useful when testing complex systems with large numbers of input parameters.

Orthogonal Array

Orthogonal Array Testing is a test design technique that helps in selecting a subset of test cases from a large number of possibilities. It is based on the principles of combinatorial mathematics and is used to reduce the number of test cases required for thorough testing of software. This technique is used to test software that has many input variables or parameters, where each variable has multiple values.

The main idea behind orthogonal array testing is to test all possible combinations of input variables with minimum test cases. Orthogonal arrays are tables with a fixed number of rows and columns, where each column represents an input parameter and each row represents a test case. The values in the table are chosen in such a way that each row represents a unique combination of values for the input parameters.

Error Guessing

Error Guessing is a test design technique that involves guessing the errors or defects that might occur in the system based on the tester's experience, knowledge, and intuition. In this technique, testers identify potential errors or defects by brainstorming, analyzing previous defects, and using their experience and intuition to anticipate where errors might occur.

The focus is on identifying defects that are likely to occur in the system, rather than following a structured approach. The errors identified are then used to design test cases that can detect those errors. Error guessing is an effective technique when used in conjunction with other test design techniques.

Exploratory Testing

Exploratory Testing is an approach to testing where the tester designs and executes test cases simultaneously. The tester uses his/her skills, experience, and creativity to design the test cases on the fly. The objective of exploratory testing is to find defects that might not be found in formal test cases.

This approach is particularly useful when the requirements are not clear or when the application is complex and difficult to test with formal test cases. Exploratory testing is also useful when there is not enough time to design and execute formal test cases, or when the application is changing rapidly. Exploratory testing is usually performed manually, but there are also tools available that support this approach.

User Story Testing

User Story Testing is a test design technique that focuses on the end user's perspective by using user stories as a basis for test cases. User stories are short descriptions of a feature or functionality of a software application from the perspective of an end-user, written in simple and concise language.

In User Story Testing, testers work closely with product owners, business analysts, and developers to identify user stories and break them down into testable scenarios.

These scenarios are then used to develop test cases that verify the functionality of the software application. User Story Testing is an Agile methodology that ensures that the software application is designed and developed with the user in mind, resulting in a better user experience. By focusing on user stories, User Story Testing helps ensure that the software application meets the needs and expectations of the end-users.


In conclusion, test design techniques are essential in software testing and play a critical role in ensuring that software systems are tested thoroughly, efficiently, and effectively.


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