Why are fixtures used in software testing?

Fixtures in testing are used for preparing and configuring the test environment before executing tests. They ensure the creation of necessary conditions, such as data initialization, system state configuration, or creation of required objects, so that tests are repeatable and isolated. After the test execution, fixtures can clean up or reset the state to avoid affecting subsequent tests.

Example: when testing a database operation function, a fixture might create a test table and populate it with test data, and after the test, delete the table.