anchor.diff:  == 测试套件结构
   
   // 翻译中。。。。（yuansheng）
  +
  +使用 `Test::Nginx` 驱动我们的测试套件，通常会用一个公共的目录结构以及规范的测试文件名样式，用来组织我们的测试集合。
  +这些会让用户更容易明白，这些测试用例在项目源码中的目录关系，以及测试用例的使用情况。
  +它不是必须的，然而，按照这种常见惯例组织，还是非常推荐的。
   
   Projects using `Test::Nginx` to drive their test suites usually have a
   common directory layout and common test file name patterns to organize
  
positive.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
  
negative.code: 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
  