CH05.L06 . BBT-5-Use case

Summary

The video script discusses the use case technique in software testing, focusing on its role in black box testing. It explains the components of a use case, including actors, preconditions, and post-conditions, using a banking ATM as an example. The script highlights the extraction of test cases from use case diagrams, emphasizing the initial number of cases and the potential for further case extraction through techniques like Equivalence Partitioning (EP) or Boundary Value Analysis (BVA). The summary underscores the importance of the use case approach for assessing the system's main functionality externally.

Takeaways

• 💼 The script discusses the role of a software designer in creating models of documentation and requirements, focusing on the 'Use case' method.
• 🔍 'Use case' is highlighted as a technique for Black box testing, from which test cases can be derived.
• 👥 The 'Use case' includes key components such as Actors, Preconditions, and Post-conditions.
• 🏦 An example of a Use case diagram is provided for a banking ATM system, illustrating how it can be used to identify actors and their interactions.
• 👨‍💼 The actors in the ATM Use case diagram are the customer, ATM technician, and bank.
• 💳 A precondition mentioned is that the customer must have an account to use the software.
• 💰 Post-conditions relate to the financial transactions affecting the credit status of the actors.
• 📈 Six test cases are planned to be extracted from the Use case diagram, with a focus on the customer and technician actors.
• 🔎 The script emphasizes the importance of further detail extraction for each test case, potentially using other techniques like EP or BVA.
• 🔑 The Use case technique is described as being applicable for the whole system, focusing on external interactions and main functionalities.

Q & A

What is a 'Use case' in software design?

A 'Use case' is a technique used in software design to describe a sequence of actions that a system performs to achieve a specific goal. It is often used for black box testing to extract test cases.

What are the key components of a use case?

The key components of a use case include actors, preconditions, and post-conditions. Actors are those who will use the software, preconditions are the requirements that must be met before using the software, and post-conditions describe the state of the system after the actor has used it.

How can use cases be used for testing software?

Use cases can be used for testing software by extracting test cases from them. These test cases can then be used to verify that the software behaves as expected under various scenarios.

What is a black box testing technique?

Black box testing is a testing technique where the tester focuses on the output of the software without considering the internal workings. It is used to test the functionality of the software from the user's perspective.

What are the three actors identified in the use case diagram of a banking ATM?

The three actors identified in the use case diagram of a banking ATM are the customer, the ATM technician, and the bank.

What is the precondition for a customer using the banking ATM software?

The precondition for a customer using the banking ATM software is that the customer must have an account.

What are post-conditions in the context of a use case?

Post-conditions in a use case describe the state of the system after the actor has used it to achieve the required scenario and reach the targeted results.

How many test cases can be extracted from the use case diagram of a banking ATM?

From the use case diagram of a banking ATM, six test cases can be extracted: four from the customer actor and two from the technician actor.

What is the importance of considering the main function when creating test cases?

Considering the main function when creating test cases is important because it helps ensure that all necessary test cases are identified. It also allows for the extraction of additional test cases using techniques like Equivalence Partitioning (EP) or Boundary Value Analysis (BVA).

How can further test cases be extracted from a main function?

Further test cases can be extracted from a main function by using detailed techniques such as Equivalence Partitioning (EP) or Boundary Value Analysis (BVA) to identify specific scenarios and edge cases that need to be tested.

What is the role of a use case diagram in software testing?

A use case diagram provides a visual representation of the interactions between actors and the system. It helps in identifying the initial number of test cases to be written and understanding the main functionality of the system from an external perspective.

Outlines

00:00

🛠 Use Case Modeling for Software Testing

This paragraph delves into the software design process, focusing on the use of 'Use case' as a critical method for black box testing. It explains the concept of actors, preconditions, and post-conditions within the use case, using a banking ATM as an example. The diagram from the software designer reveals three actors: a customer, an ATM technician, and the bank itself. The precondition is that the customer must have an account to use the software, while post-conditions are tied to financial transactions affecting the customer's credit. The paragraph outlines the extraction of six test cases from the use case diagram, four for the customer and two for the technician. It also touches on the potential for further test case extraction using other techniques like Equivalence Partitioning (EP) or Boundary Value Analysis (BVA) for detailed testing of specific functions within the main functionality.

Keywords

💡Software Designer

A software designer is a professional who creates the blueprint for software applications. They are responsible for defining the architecture, components, and interactions of a software system. In the context of the video, the software designer is developing models of documentation and requirements, which are crucial for understanding the functionality and expectations of the software being developed.

💡Use Case

A use case is a description of a set of actions or behaviors that a system performs in response to a set of inputs from an actor. It is a fundamental concept in software design and requirements gathering. The video emphasizes the use of use cases as a technique for black box testing, from which test cases can be derived. This helps ensure that the software meets the needs and expectations of its users.

💡Black Box Testing

Black box testing is a method of software testing where the tester focuses on the functionality of the software without considering the internal structure or implementation. It is used to ensure that the software behaves as expected from an external perspective. In the video, use cases are used to derive test cases for black box testing, highlighting the importance of understanding the software's behavior from the user's point of view.

💡Actors

In the context of use cases, actors represent the entities that interact with the software system. They can be users, external systems, or other software components. The video mentions three actors in the use case diagram of a banking ATM: the customer, the ATM technician, and the bank. Understanding the roles and interactions of these actors is essential for designing effective test cases.

💡Preconditions

Preconditions are the conditions that must be met before an actor can initiate a use case. They are essential for defining the context in which a use case is valid. In the video, the precondition for using the banking ATM software is that the customer must have an account. This sets the stage for the interactions that will be tested in the software.

💡Post-conditions

Post-conditions describe the state of the system after a use case has been completed. They help define the expected outcomes of a use case. In the video, post-conditions for the banking ATM software include changes in the credit status of the customer based on financial transactions. These conditions are crucial for verifying that the software functions correctly.

💡Use Case Diagram

A use case diagram is a visual representation of the use cases of a system, showing the relationships between actors and use cases. It is a key tool in software design for understanding the interactions and requirements of a system. The video discusses a use case diagram for a banking ATM, which includes actors and their associated use cases, providing a clear overview of the system's functionality.

💡Test Cases

Test cases are detailed descriptions of the steps that a tester will follow to verify that a specific part of the software works as expected. They are derived from use cases and are crucial for ensuring software quality. The video mentions extracting test cases from the use case diagram, with six test cases identified, four for the customer actor and two for the technician actor.

💡Check Balances

In the context of the video, 'check balances' refers to a specific functionality within the banking ATM software. It is a test case derived from the use case diagram, which verifies that the system correctly displays the customer's account balance. This test case is an example of how detailed testing can be conducted to ensure that the software meets its requirements.

💡EP or BVA Techniques

EP (Equivalence Partitioning) and BVA (Boundary Value Analysis) are techniques used in software testing to derive test cases. They help in identifying different scenarios and edge cases that need to be tested. The video suggests using these techniques to write detailed test cases for the 'check balances' functionality, demonstrating a deeper level of testing beyond the initial use case analysis.

💡Main Function

The main function in software design refers to the primary functionality or entry point of the software. It is the core component that drives the system's operations. In the video, the main function is the focus for creating test cases, ensuring that the fundamental operations of the software are thoroughly tested and validated.

Highlights

The importance of software designers in creating models of documentation and requirements.

Use case as a defining technique for black box testing.

Extraction of test cases from use cases.

Definition of actors in use cases.

Explanation of preconditions in use cases.

Clarification of post-conditions in use cases.

Use case diagram example of a banking ATM.

Identification of three actors in the ATM use case.

Precondition of having an account for using the ATM software.

Post-conditions related to financial transactions in the ATM use case.

Extraction of six test cases from the ATM use case.

Distribution of test cases among customer and technician actors.

Use of the use case diagram for initial test case extraction.

Potential for further test case extraction from main functions.

Application of EP or BVA techniques for detailed test case creation.

Use case technique's role in testing the whole system externally and for main functionality.

Transcripts

The software designer, designs several models

of documentation and requirements.

One of the defining ways of requirements

is "Use case", which can use

as a technique for Black box testing,

and we can extract from it the test cases

that we will use. It consists of:

Actors: those who will

use the software.

Preconditions: the requirements

that actor should have

before using the software.

Post-conditions: the state of the system

after the actor has used it,

to achieve the required scenario

and reached the targeted results

This example is for Use case diagram

of a banking ATM, received from

the software designer.

from this diagram, there are

3 actors: customer, ATM technician

and bank. the precondition is that

customer must have an account

before using the software.

post-conditions: according to

the financial transactions, the credit

increases and decreases with the actor.

through the cases written in

the rectangle, I can specify that

We will extract 6 test cases from it

4 test cases from

the customer actor, and 2 test

cases from the technician actor.

so, from the Use case diagram,we extracted

the initial number of test cases to be written.

There an important point to take care of,

Each test case created

to the main function may ,later on, has

another technique to extract test cases

in details. For example,

we extracted a test case for the check balances.

There may be other details

inside this function that I need to

create test cases for it. so I'll

use EP or BVA techniques

to write them. while this

Use case technique is used for the whole system

externally, and for main functionality.