To write integration tests with PHPUnit to validate system-level behavior, you can follow these steps:
Set up the test environment: Create a separate directory for integration tests and set up the necessary dependencies and configurations. This may include connecting to the database, initializing the framework or system, and preparing any required test data.
Identify the high-level functionality to test: Determine the system-level behavior you want to validate, such as an end-to-end workflow, the interaction between different components, or the behavior of an API.
Write the test case: Extend the PHPUnit\Framework\TestCase class to create a new test case for the integration test. In the test case, write methods to define the specific test scenarios and expected behavior.
Set up pre-conditions: In each test method, set up any pre-conditions required for the test scenario. This may include creating database records, mocking API responses, or initializing specific system states.
Perform actions and assert the expected behavior: In each test method, perform the necessary actions that need to be tested and assert the expected behavior or outcome using assertions provided by PHPUnit. This may include making API requests, simulating user interactions, or calling system functions.
Clean up after tests: Ensure that any changes made during the test are cleaned up afterward, restoring the system to its initial state. This may involve deleting temporary files, removing test records from the database, or rolling back transactions.
Run the integration tests: Execute the integration tests using the PHPUnit command-line test runner or a test runner integrated into your development environment. Analyze the test results to identify any failures or issues.
Refine and iterate: If any integration tests fail, investigate and fix the issues in the code or configuration. Modify the test cases as needed to cover additional scenarios or edge cases.
By following these steps, you can write integration tests with PHPUnit to validate the system-level behavior of your application. This helps ensure that the different components and functionalities work together as expected.