4. What is a test case?

A test case in software engineering is a set of conditions or variables under which a tester will determine whether a system under test satisfies requirements or works correctly. The process of developing test cases can also help find problems in the requirements or design of an application, since it requires completely thinking through the operation of the application.

Here are the steps to create a test case:

1. Identify the Expected Output: The first step in creating a test case is to identify the expected output of the system under certain conditions. This could be the result of a calculation, the response to a particular input, or the behavior of the system under certain conditions.

2. Define Test Case Conditions: Next, you need to define the conditions under which the test will be run. This could include the initial state of the system, the inputs provided to the system, and the sequence of actions that will be performed.

3. Execute the Test Case: Once the conditions have been defined, the test case can be executed. This involves setting up the system in the specified initial state, providing the inputs, and performing the actions.

4. Compare Actual and Expected Results: After the test case has been executed, the actual output of the system is compared to the expected output. If they match, the test case has passed. If they do not match, the test case has failed, indicating a potential problem with the system.

5. Document the Test Case: Finally, the test case should be documented so that it can be reused in the future. This documentation should include the conditions, the expected output, and the actual output. It may also include any notes or observations made during the execution of the test case.