How do you deal with state dependencies and concurrency issues in state transition testing?

1 State dependencies

State dependencies are situations where the outcome of a test case depends on the previous state or history of the system. For instance, if you are testing a shopping cart, you may need to add items, apply discounts, and check out in a certain order to verify the correct functionality. This can make test cases more complex and fragile, as they may fail if the system does not follow the expected sequence of states. To address this issue, you can employ test data management tools to create and restore consistent data sets for each test case. Additionally, you can use state diagrams or tables to document and visualize the possible states and transitions of the system, and design your test cases accordingly. Test automation tools can be used to execute your test cases in a predefined and repeatable order, and verify the expected state after each transition. Furthermore, state-based assertions or checkpoints can validate the current state of the system at any point of the test case, and report any deviations.

3 State transition testing examples

To illustrate how state transition testing works and how to deal with state dependencies and concurrency issues, let's look at some examples. Suppose you are testing a web application that allows users to create and manage projects. This application has four main states: logged out, logged in, project created, and project deleted. These states are triggered by events like login, logout, create project, delete project, or session timeout. As an example, you can test if a user can log in and create a project by starting from the logged out state, performing the login event with valid credentials, verifying that the system transitions to the logged in state, performing the create project event with valid data, verifying that the system transitions to the project created state, and verifying that the project details are correct. Additionally, you can verify that a user can delete a project and log out by starting from the project created state, performing the delete project event with valid confirmation, verifying that the system transitions to the logged in state, performing the logout event, verifying that the system transitions to the logged out state, and verifying that the project is no longer accessible. Furthermore, you can check if a user cannot create a project with the same name as an existing one by starting from the project created state and performing the create project event with the same name as an existing one. Then verify that the system does not transition to the project created state and verify that an error message is displayed. Lastly, you can check if a user cannot delete a project that is being edited by another user by starting from the project created state with two concurrent users. Then perform the edit project event with one user and perform the delete project event with another user. Verify that the system does not transition to the logged in state and verify that a warning message is displayed. By using state transition testing, you can ensure your system behaves correctly when it changes from one state to another. It also helps you handle any potential dependencies or concurrency issues while improving your test coverage, quality, and reliability of your system.

4 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?