diff --git a/docs/sources/contributing/devenvironment.rst b/docs/sources/contributing/devenvironment.rst
index f0a1398d70..42e6f9be84 100644
--- a/docs/sources/contributing/devenvironment.rst
+++ b/docs/sources/contributing/devenvironment.rst
@@ -122,7 +122,10 @@ If the test are successful then the tail of the output should look something lik
 	PASS
 	ok  	github.com/dotcloud/docker/utils	0.017s
 
+If $TESTFLAGS is set in the environment, it is passed as extra arguments to 'go test'.
+You can use this to select certain tests to run, eg.
 
+    TESTFLAGS='-run ^TestBuild$' make test
 
 
 Step 6: Use Docker