What potential issues could arise when using session variables for testing in PHP?

One potential issue when using session variables for testing in PHP is that the session data may persist between tests, leading to unexpected behavior or test failures. To solve this, you can manually unset or destroy the session data at the end of each test to ensure a clean slate for the next test.

// Clear session data at the end of each test
session_start();
session_unset();
session_destroy();