From d3ceee50430f77e2c3672f2ae925e29b28400186 Mon Sep 17 00:00:00 2001
From: Eric Vergnaud <eric.vergnaud@wanadoo.fr>
Date: Sat, 24 Sep 2016 00:02:18 +0800
Subject: [PATCH] Enhancing the doc

---
 doc/adding-tests.md | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/doc/adding-tests.md b/doc/adding-tests.md
index 769383d31..4da6d4093 100644
--- a/doc/adding-tests.md
+++ b/doc/adding-tests.md
@@ -63,7 +63,22 @@ TestTemplates ::= [
 ...
 ```
 
-For every name mentioned, you will find a `.stg` file with the actual test. E.g., `Sets/StarSet.stg`:
+For every name mentioned, you will find a `.stg` file with the actual test template. E.g., `Sets/StarSet.stg`.
+
+Each `.stg` file descripes the following mandatory elements for the test:
+ - the test type: "Parser" or "Lexer"
+ - some ANTLR options, such as "Debug"
+ - the grammar 
+ - the start rule
+ - the input i.e. the text to parse
+ - the expected output
+ - the expected errors
+
+The grammar can itself contain template expressions such as <something>.
+The test generator replaces these with the corresponding values from the target language template (see below).
+It then generates a unit test in which the grammar, the input and the expected output and errors are inlined.
+ 
+Here is an example test template:
 
 ```
 TestType() ::= "Parser"
@@ -92,6 +107,7 @@ a : ('a'|'b')* 'c' {<InputText():writeln()>} ;
 >>
 ```
 
+
 ### Cross-language actions embedded within grammars
 
 To get: