--- oe-selftest.origin	2015-06-09 16:01:24.048627485 +0800
+++ oe-selftest	2015-06-15 14:44:36.680849828 +0800
@@ -38,6 +38,13 @@
 from oeqa.utils.commands import runCmd, get_bb_var, get_test_layer
 from oeqa.selftest.base import oeSelfTest
 
+# add test cases location into the python searching path
+for l in get_bb_var('BBPATH').split(':'):
+    if os.path.exists(os.path.abspath(os.path.join(l, 'lib/oeqa/selftest'))):
+        sys.path.insert(0, os.path.abspath(os.path.join(l, 'lib')))
+# reloading this package is necessary due to "sys.path" updated
+reload(oeqa.selftest)
+
 def logger_create():
     log = logging.getLogger("selftest")
     log.setLevel(logging.DEBUG)
@@ -127,11 +134,18 @@
     for x in exclusive_modules:
         testslist.append('oeqa.selftest.' + x)
     if not testslist:
-        testpath = os.path.abspath(os.path.dirname(oeqa.selftest.__file__))
-        files = sorted([f for f in os.listdir(testpath) if f.endswith('.py') and not (f.startswith('_') and not include_hidden) and not f.startswith('__') and f != 'base.py'])
-        for f in files:
-            module = 'oeqa.selftest.' + f[:-3]
-            testslist.append(module)
+        # add test cases to "testslist" for *every* subfolder under "oeqa/selftest/"
+        def _addtest(args, dname, fnames):
+            if (os.path.basename(dname) != 'files'): # 'files' folder is ignored. it is for test data. 
+                d=dname[args[0]:].replace('/','.') # d is the sub-package name. eg: "oeqa/selftest/cfg/mytest.py", d=cfg
+                for f in fnames:
+                    if (f.endswith('.py') and not (f.startswith('_') and not include_hidden) and not f.startswith('__') and f != 'base.py'):
+                        testslist.append('oeqa.selftest'+d+'.'+f[:-3]) # test is added as "oeqa.selftest.cfg.mytest"
+        # detect test cases from all layers that added to "BBPATH"
+        for l in get_bb_var('BBPATH').split(':'):
+            testpath = os.path.join(l, 'lib', 'oeqa', 'selftest')
+            if os.path.exists(testpath):
+                os.path.walk(testpath, _addtest, [len(testpath)])
 
     return testslist
 
@@ -146,7 +160,9 @@
         log.info('Listing all available test modules:')
         testslist = get_tests(include_hidden=True)
         for test in testslist:
-            module = test.split('.')[-1]
+            # list test with its sub-package name, relative to oeqa.selftest. 
+            # eg: "oeqa.selftest.cfg.mytest" is listed as "cfg.mytest"
+            module = test.split('.',2)[-1]
             info = ''
             if module.startswith('_'):
                 info = ' (hidden)'