update doc

README.md

@@ -114,6 +114,10 @@ Launch Fess Server and run the following command:
 
     $ mvn test -P integrationTests -Dtest.fess.url="http://localhost:8080" -Dtest.es.url="http://localhost:9201"
 
+To run a single test case, you can use:
+
+    $ mvn test -P integrationTests -Dtest.fess.url="http://localhost:8080" -Dtest.es.url="http://localhost:9201 -Dtest=SearchApiTests"
+
 ### Translate In Your Language
 
 Fess is internationalized software.