[Documentation] Add guidelines for grouping tests together.

This was considered a good practice but it was not documented. Now it is.

Differential Revision:	http://reviews.llvm.org/D14733

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253281 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/docs/TestingGuide.rst b/docs/TestingGuide.rst
index adf5f3d4cfbde11f715ecc87ebffb2bcfd849878..134ddd88c87d5a63fc8d4c6810cb3d51287fbf59 100644 (file)
--- a/docs/TestingGuide.rst
+++ b/docs/TestingGuide.rst
@@ -240,6 +240,10 @@ The recommended way to examine output to figure out if the test passes is using
 the :doc:`FileCheck tool <CommandGuide/FileCheck>`. *[The usage of grep in RUN
 lines is deprecated - please do not send or commit patches that use it.]*
 
+Put related tests into a single file rather than having a separate file per
+test. Check if there are files already covering your feature and consider
+adding your code there instead of creating a new file.
+
 Extra files
 -----------