The Three Laws of TDD（测试驱动开发的三条原则）

 

1. You are not allowed to write any production code unless it is to make a failing unit test pass.

 

2. You are not allowed to write any more of a unit test than is sufficient to fail; and compilation failures are failures.

 

3. You are not allowed to write any more production code than is sufficient to pass the one failing unit test.