oeqa/{core,selftest}: Add support to validate if a specified test case isn't found

If some test module/case is specified to run and isn't found the OEQA
framework didn't notice it, so complete the implementation using
modules_required and validate for the test case prescense.

Raise an exception when the test module/case required isn't found.

[YOCTO #11645]

(From OE-Core rev: e50b415aaaa1581473f85f0a8afa278b5f95129b)

Signed-off-by: Aníbal Limón <anibal.limon@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oeqa/core/loader.py

@@ -9,6 +9,7 @@ import inspect
 from oeqa.core.utils.path import findFile
 from oeqa.core.utils.test import getSuiteModules, getCaseID
 
+from oeqa.core.exception import OEQATestNotFound
 from oeqa.core.case import OETestCase
 from oeqa.core.decorator import decoratorClasses, OETestDecorator, \
         OETestFilter, OETestDiscover
@@ -277,6 +278,28 @@ class OETestLoader(unittest.TestLoader):
 
         return self.suiteClass(suite)
 
+    def _required_modules_validation(self):
+        """
+            Search in Test context registry if a required
+            test is found, raise an exception when not found.
+        """
+
+        for module in self.modules_required:
+            found = False
+
+            # The module name is splitted to only compare the
+            # first part of a test case id.
+            comp_len = len(module.split('.'))
+            for case in self.tc._registry['cases']:
+                case_comp = '.'.join(case.split('.')[0:comp_len])
+                if module == case_comp:
+                    found = True
+                    break
+
+            if not found:
+                raise OEQATestNotFound("Not found %s in loaded test cases" % \
+                        module)
+
     def discover(self):
         big_suite = self.suiteClass()
         for path in self.module_paths:
@@ -291,6 +314,9 @@ class OETestLoader(unittest.TestLoader):
         for clss in discover_classes:
             cases = clss.discover(self.tc._registry)
 
+        if self.modules_required:
+            self._required_modules_validation()
+
         return self.suiteClass(cases) if cases else big_suite
 
     def _filterModule(self, module):