avocado/core/job.py: move test suite validation to create_test_suite

This is the right place to criticize the test suite.  Even though I
don't feel it's right to abort the application from within the job
class, this prevents the current user experience to break.

In the near future, I'd like to see removed, and avocado runs without
a test suite to run and give these exact results: no tests were
available to be run, so none were executed.
Signed-off-by: NCleber Rosa <crosa@redhat.com>

avocado/core/job.py

@@ -429,6 +429,17 @@ class Job(object):
             stacktrace.log_exc_info(sys.exc_info(), 'avocado.app.debug')
             raise exceptions.OptionValidationError(details)
 
+        if not self.test_suite:
+            if self.references:
+                references = " ".join(self.references)
+                e_msg = ("No tests found for given test references, try "
+                         "'avocado list -V %s' for details" % references)
+            else:
+                e_msg = ("No test references provided nor any other arguments "
+                         "resolved into tests. Please double check the executed"
+                         " command.")
+            raise exceptions.OptionValidationError(e_msg)
+
     def pre_tests(self):
         """
         Run the pre tests execution hooks
@@ -441,17 +452,6 @@ class Job(object):
         self._job_pre_post_dispatcher.map_method('pre', self)
 
     def run_tests(self):
-        if not self.test_suite:
-            if self.references:
-                references = " ".join(self.references)
-                e_msg = ("No tests found for given test references, try "
-                         "'avocado list -V %s' for details" % references)
-            else:
-                e_msg = ("No test references provided nor any other arguments "
-                         "resolved into tests. Please double check the executed"
-                         " command.")
-            raise exceptions.OptionValidationError(e_msg)
-
         mux = getattr(self.args, "mux", None)
         if mux is None:
             mux = multiplexer.Mux()

selftests/unit/test_job.py

@@ -6,6 +6,7 @@ if sys.version_info[:2] == (2, 6):
 else:
     import unittest
 
+from avocado.core import exceptions
 from avocado.core import test
 from avocado.core import job
 from avocado.core import exit_codes
@@ -42,8 +43,8 @@ class JobTest(unittest.TestCase):
     def test_job_create_test_suite_empty(self):
         args = argparse.Namespace()
         myjob = job.Job(args)
-        myjob.create_test_suite()
-        self.assertEqual(myjob.test_suite, [])
+        self.assertRaises(exceptions.OptionValidationError,
+                          myjob.create_test_suite)
 
     def test_job_create_test_suite_simple(self):
         simple_tests_found = self._find_simple_test_candidates()