State Transition Testing

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State Transition Testing in SDLC

In this article, I am going to discuss State Transition Testing in SDLC. Please read our previous article where we discussed Cause-Effect Graph Testing. At the end of this article, you will understand the following important pointers which are related to State Transition Testing in SDLC.

1. What is State Transition Testing?
2. When Should a State Transition Be Used?
3. When Should State Transition Not Be Used?
4. State Transition Diagram
5. What are the Objectives of State Transition Testing?
6. Example of State Transition Testing
7. What are the Advantages of State Transition?
8. What are the Disadvantages of State Transition?

What is State Transition Testing?

State Transition Testing is a sort of software testing that examines how the state of the application changes in response to different inputs. The input that was passed undergoes a condition change, and the state change is apparent. In essence, state transition testing is a type of black-box testing used to look at how a system or application responds to a set of different input conditions. Giving the system both positive and negative input values while also monitoring the system’s behavior constitutes this type of testing. State Transition Testing is a type of black box testing in which alterations to the input circumstances result in modifications to the state or output of the Application Under Test (AUT). Testing for state transitions assists in analyzing an application’s behavior under various input scenarios. The system behavior can be recorded while testers offer both positive and negative input test values.

When Should a State Transition Be Used?

1. When testing an application for a limited set of input values, this might be employed.
2. When testing the sequence of events that take place within the application being tested. In other words, this will let the tester examine the behavior of the program for a series of input values.
3. When the system being tested is dependent on previous events or values.

When Should State Transition Not Be Used?

1. When input combinations with sequential timing are not tested.
2. If testing is required for several functionalities, such as exploratory testing.

State Transition Diagram

The state transition technique is a black box testing approach that concentrates on how a system behaves when it changes states. It entails figuring out the system’s many states and testing the changes between them. The four main elements of the state transition technique are as follows:

• States: The various circumstances or modes in which a system may exist are represented by states. Each state is coupled with a collection of traits or qualities that determine its behavior. Among the possible states are “logged in,” “logged out,” “idle,” and “processing.”
• Events: The stimuli or triggers that cause the system to change from one state to another are known as events. They stand in for actions or inputs the system experiences that may cause a change in its state. There are internal and external events. While external events are inputs from the outside environment, internal events are produced by the system itself. The occurrence of some events can take the form of “clicking a button,” “receiving a message,” or “timing out.”
• Transitions: A transition is a change in a system’s status in response to an external event. They specify the guidelines or constraints that control how the system responds when a given event takes place in a particular state. Transitions frequently include modifications to the system’s characteristics or behaviors. For instance, the system might switch to the state “logged in” when the event “clicking a button” takes place when it is in the “logged out” state.
• Actions/Outputs: The effects or results of the system changing states are represented by actions or outputs. They explain the changes that are observable or quantifiable that come from a transition. The display of data on the user interface, the creation of reports, or the updating of databases are examples of actions. Testing personnel can determine if the system operates properly during state transitions by reviewing the anticipated actions or results.

What are the Objectives of State Transition Testing?

State Transition testing’s goal is to:

• To evaluate how the system responds to different inputs.
• To evaluate the reliance on historical values.
• To evaluate how the application’s transition state has changed.
• To evaluate the system’s effectiveness.

Example of State Transition Testing

In the diagram below, a system transition is depicted as follows:

The possible situations that need to be evaluated are listed below. The tests are developed from the aforementioned state and transition.

Test	Test1	Test2	Test3
Start State	Off	On	On
Input	Switch ON	Switch off	Switch off
Output	Light ON	Light off	Fault
Finish State	ON	OFF	ON

What are the Advantages of State Transition?

Black box testing’s state transition technique has the following benefits:

1. Comprehensive Testing: By identifying and testing different states and transitions, it enables full coverage of the behavior of the system.
2. System Grasp: It aids testers in developing a better grasp of the underlying workings of the system, allowing them to produce test cases that are more fruitful.
3. Identifying flaws in the timing and sequence of state changes is possible via state transition testing.
4. Efficiency: It achieves great test coverage while using the fewest possible test cases, saving time and money.
5. Robustness Testing: It makes it easier to recognize boundary and error conditions, hence exposing weaknesses and assuring that the system can withstand unexpected inputs.

What are the Disadvantages of State Transition?

Black box testing’s state transition technique has various drawbacks despite being beneficial in specific circumstances. Here is a handful in the succinct form:

1. Complexity: As the system’s states and transitions grow in number, state transition testing gets more difficult. It can be difficult and time-consuming to manage many states and transitions.
2. Complete coverage of all potential state transitions is impossible to guarantee, especially in complex systems. Potential defects or vulnerabilities may go unnoticed if certain states or transitions are missed.
3. Lack of Visibility: Black box testing does not reveal information about the internal operations or code architecture because it concentrates on the external behavior of the system. Finding the primary reasons for failures or flaws becomes more difficult as a result.
4. Dependency on Specifications: The accuracy and thoroughness of the specifications or requirements documentation is crucial for state transition testing. The efficiency of this method can be hampered by unclear or incomplete specifications.
5. Limited Fault Detection: While state transition testing is good at finding some faults connected to state changes, it may not be as successful at finding other sorts of flaws, such as calculation errors or boundary conditions.

In the next article, I am going to discuss Use Case Testing Technique. Here, in this article, I try to explain State Transition Testing in SDLC. I hope you enjoy this State Transition Testing article.