test/unit: README updated with more details about running unit tests

test/unit/README

@@ -1,7 +1,11 @@
+Kamailio Test Unit
+==================
+
 This directory contains some small "smoke tests", that should assure that
 basic functionality of the server work as required. This tests should consists
 of one shell script and a config file if needed. They should not need much time
 for execution, to allow the run of the complete test suite in a few seconds.
+
 All test scripts must be self-contained, should not have external dependencies
 and must clean up after they are run. The second line in each scripts should
 contain a small comment that describe the task of the test, it should not
@@ -10,3 +14,18 @@ output any messages on successful runs.
 This tests should (in the current state) only run by developers who know
 what they do. They could delete your database, produce core dumps that fill
 your harddisk or do other nasty things..
+
+Usage
+-----
+
+To execute all unit tests, run:
+
+    make all
+
+To run a specific unit test, run:
+
+    make run UNIT=scripname
+
+Scriptname is the name of shell file to execute, for example:
+
+    make run UNIT=1.sh