[pitivi] docs: Fix explanation to run a single test

[Thibault Saunier <tsaunier src gnome org>]

commit 458cb3b2fb67ad3220db9e39688ba980d6150cc0
Author: Thibault Saunier <tsaunier gnome org>
Date:   Fri Jun 16 17:40:38 2017 -0400

    docs: Fix explanation to run a single test

 docs/Testing.md |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)
---
diff --git a/docs/Testing.md b/docs/Testing.md
index d77a624..b901e06 100644
--- a/docs/Testing.md
+++ b/docs/Testing.md
@@ -18,7 +18,11 @@ You can run the unit tests with:
 
 If you want to run only one particular unit test, use:
 
-`nose2 tests test_project.TestProjectManager.testLoadProjectFailedUnknownFormat`
+`gst-validate-launcher tests/run_testsuite.py -t 
tests.test_project.TestProjectManager.testLoadProjectFailedUnknownFormat`
+
+Listing tests:
+
+`gst-validate-launcher tests/run_testsuite.py -L`
 
 ### Writing unit tests