单元测试不处理数据库、文件系统或任何可能延长测试运行时间的内容；因而，从第一天就可以编写单元测试。

Unit tests don't deal with databases, file systems, or anything else that would tend to make tests run longer; consequently, unit tests can be written from day one.

youdao

单元测试不处理数据库、文件系统或任何可能延长测试运行时间的内容；因而，从第一天就可以编写单元测试。

Unit tests don't deal with databases, file systems, or anything else that would tend to make tests run longer; consequently, unit tests can be written from day one.

youdao