回归测试是软件测试的一种，旨在检验软件原有功能在修改后是否保持完整。

1. 识别出软件中被修改的部分
2. 从原基线测试用例库「T」中，排除所有不再适用的测试用例，确定对新版本依然有效的测试用例，创建新的基线测试用例库「TN」
3. 依据一定的策略从TN中选择测试用例测试被修改的软件
4. 如果必要，生成新的测试用例集「T1」，用于测试TN无法充分测试的软件部分
5. 用T1执行修改后的软件

• 第2和第3步测试验证修改是否破坏了现有的功能，第4和第5步测试验证修改工作本身。

Regression testing is a type of software testing that verifies that software previously developed and tested still performs correctly after it was changed or interfaced with other software. Changes may include software enhancements, patches, configuration changes, etc. During regression testing, new software bugs or regressions may be uncovered. Sometimes a software change impact analysis is performed to determine what areas could be affected by the proposed changes. These areas may include functional and non-functional areas of the system.