add title

docs/contributing/coding-style.md

@@ -526,9 +526,11 @@ make make gotests/gen
 ```
 
 After the command above executed, the file `*target*_test.go` will be generated for each Go source file.
-The test code generated follows the table-driven test format. 
+The test code generated follows the table-driven test format.
 You can implement your test code under the `tests` variable generated following the table-driven test format.
 
+### Customize test case
+
 We do not suggest to modify the generated code other than the `tests` variable, but in some cases, you may need to modify the generated code to meet your requirement, for example:
 
 1. init() function