avocado.job: Refactor and introduce new error codes for job

We have to tell apart 'expected' avocado error from
plain crashes. Refactor the Job.run() method, separating
it to an unhandled exception auxiliary method, and a
handled one, that properly sets the following return
codes for avocado execution:

* AVOCADO_ALL_OK (0)
    Both job and tests PASSed
* AVOCADO_TESTS_FAIL (1)
    Job went fine, but some tests FAILed or ERRORed
* AVOCADO_JOB_FAIL (2)
    Something went wrong with the Job itself, by explicit
    :class:`avocado.core.exceptions.JobError` exception.
* AVOCADO_CRASH (3)
    Something else went wrong and avocado plain crashed.
Signed-off-by: NLucas Meneghel Rodrigues <lmr@redhat.com>

avocado/job.py

@@ -18,11 +18,15 @@ Class that describes a sequence of automated operations.
 import imp
 import logging
 import os
+import sys
+import traceback
 import uuid
 
 from avocado.core import data_dir
 from avocado.core import output
 from avocado.core import status
+from avocado.core import exceptions
+from avocado.core import error_codes
 from avocado import test
 from avocado import result
 
@@ -93,16 +97,17 @@ class Job(object):
                                         self.args)
         return test_result
 
-    def run(self, urls=None):
+    def _run(self, urls=None):
         """
-        Main job method. Runs a list of test URLs to its completion.
+        Unhandled job method. Runs a list of test URLs to its completion.
 
         :param urls: String with tests to run.
 
-        :return: Integer with overall job status
-                 0 - Job passed, all tests passed
-                 1 - Job passed, some/all tests failed
-                 2 - Job failed
+        :return: Integer with overall job status. See
+                 :mod:`avocado.core.error_codes` for more information.
+        :raise: Any exception (avocado crashed), or
+                :class:`avocado.core.exceptions.JobBaseException` errors,
+                that configure a job failure.
         """
         failures = []
         if urls is None:
@@ -123,16 +128,37 @@ class Job(object):
         # Let's clean up test artifacts
         if not self.args.keep_tmp_files:
             data_dir.clean_tmp_files()
-        # Let's assess the overall status:
-        job_status = status.mapping[self.status]
         tests_status = not bool(failures)
-        if job_status:
-            if tests_status:
-                return 0
-            else:
-                return 1
+        if tests_status:
+            return error_codes.numeric_status['AVOCADO_ALL_OK']
         else:
-            return 2
+            return error_codes.numeric_status['AVOCADO_TESTS_FAIL']
+
+    def run(self, urls=None):
+        """
+        Handled main job method. Runs a list of test URLs to its completion.
+
+        :param urls: String with tests to run.
+
+        :return: Integer with overall job status. See
+                 :mod:`avocado.core.error_codes` for more information.
+        """
+        try:
+            return self._run(urls)
+        except exceptions.JobBaseException, details:
+            self.status = details.status
+            fail_class = details.__class__.name
+            self.output_manager.error('Avocado job failed: %s: %s' %
+                                      (fail_class, details))
+            return error_codes.numeric_status['AVOCADO_JOB_FAIL']
+        except Exception, details:
+            self.status = "ERROR"
+            exc_type, exc_value, exc_traceback = sys.exc_info()
+            tb_info = traceback.format_exception(exc_type, exc_value,
+                                                 exc_traceback.tb_next)
+            for line in tb_info:
+                self.output_manager.error(line)
+            return error_codes.numeric_status['AVOCADO_CRASH']
 
 
 class TestModuleRunner(object):