What components must be included in the test suite during regression testing?

A regression test suite must include:

• Key functional tests — verify the main functions of the system to ensure they haven't broken after changes.
• Tests for fixed defects — to ensure that bugs that were fixed have not reappeared.
• Integration tests — check the interaction between modules.
• Tests for critical business scenarios — scenarios that are important for the operation of the product and business.

Such a suite helps quickly identify regressions and guarantees system stability after changes.