anchor.diff:  to reason about the location of the test suite in a project source tree
   and the usage of the tests. It is not really required, however, to use
   this common convention; it is just highly recommended.
  +
  +按照惯例，这些项目在当前源码的根目录下，有个 `t/` 目录用来存放测试文件。
  +每个测试文件包含一些具有相同属性或关联度的测试用例，保存在扩展名为 `.t` 的文件中，可以很容易的表明它们自身是 “测试文件”。
  +下面的目录树结构，是真实项目 link:https://github.com/openresty/headers-more-nginx-module[headers-more-nginx-module] 的测试套件：
   
   By convention, such projects have a `t/` directory at the root of their
   source tree where test files reside in. Each test file contains test cases
  
positive.code: == 测试套件结构
  
  // 翻译中。。。。（yuansheng）
  
  Projects using `Test::Nginx` to drive their test suites usually have a
  common directory layout and common test file name patterns to organize
  
negative.code:     └── vars.t
  ....
  
  
  When you have many test files, you can also group them further with sub-directories
  under `t/`. For example, in the link:https://github.com/openresty/lua-nginx-module[lua-nginx-module]
  project, we have sub-directores like `023-rewrite/` and `024-access/` under
  