selftests/unit/test_jobdata.py: employ a "assertful" approach

Let's make this test more in line with the unittest.TestCase style,
making use of the assertions, whose failures can be point us to the
exact location of the failure.
Signed-off-by: NCleber Rosa <crosa@redhat.com>

selftests/unit/test_jobdata.py

@@ -14,78 +14,65 @@ class JobdataTest(unittest.TestCase):
 
     def _check_results(self, dirname):
         pth = os.path.join(BASEDIR, "selftests", ".data", dirname)
-        errs = []
+
         # pwd
-        exp = "/home/medic/Work/Projekty/avocado/avocado"
-        act = jobdata.retrieve_pwd(pth)
-        if act != exp:
-            errs.append("pwd: '%s' '%s'" % (exp, act))
+        self.assertEqual(jobdata.retrieve_pwd(pth),
+                         "/home/medic/Work/Projekty/avocado/avocado",
+                         "pwd mismatch")
 
         # references
-        exp = ["yes", "no"]
-        act = jobdata.retrieve_references(pth)
-        if act != exp:
-            errs.append("references: '%s' '%s'" % (exp, act))
+        self.assertEqual(jobdata.retrieve_references(pth),
+                         ["yes", "no"], "references mismatch")
 
         # variants
         try:
             variants = jobdata.retrieve_variants(pth)
-            act = variants.to_str(0, 99)
         except Exception as details:
-            errs.append("variants: Unable to retrieve: %s" % details)
-        else:
-            exp = ("\nVariant variant1-6ec4:    /run/variant1\n"
-                   "    /run/variant1:foo => bar\n\n"
-                   "Variant variant2-a6fe:    /run/variant2\n"
-                   "    /run/variant2:foo => baz")
-            if not act or exp not in act:
-                errs.append("variants:\n%s\n\n%s" % (exp, act))
+            self.fail("variants: Unable to retrieve: %s" % details)
+        act = variants.to_str(0, 99)
+        self.assertTrue(act)
+        exp = ("\nVariant variant1-6ec4:    /run/variant1\n"
+               "    /run/variant1:foo => bar\n\n"
+               "Variant variant2-a6fe:    /run/variant2\n"
+               "    /run/variant2:foo => baz")
+        self.assertIn(exp, act, "variants mismatch")
 
         # args
         try:
             args = jobdata.retrieve_args(pth)
         except Exception as details:
-            errs.append("args: Unable to retrieve: %s" % details)
-        else:
-            if isinstance(args, dict):
-                for scenario in [["loaders", [u"external:/bin/echo"]],
-                                 ["external_runner", u"/bin/echo"],
-                                 ["failfast", False, None],
-                                 ["ignore_missing_references", False, None],
-                                 ["execution_order", "variants-per-test",
-                                  None]]:
-                    act = args.get(scenario[0])
-                    for exp in scenario[1:]:
-                        if act == exp:
-                            break
-                    else:
-                        errs.append("args: Invalid value '%s' of key '%s' "
-                                    "%s" % (act, scenario[0],
-                                            scenario[1:]))
-            else:
-                errs.append("args: Invalid args: %s" % args)
+            self.fail("args: Unable to retrieve: %s" % details)
+        self.assertTrue(isinstance(args, dict),
+                        "args: Invalid args: %s" % args)
+        for scenario in [["loaders", [u"external:/bin/echo"]],
+                         ["external_runner", u"/bin/echo"],
+                         ["failfast", False, None],
+                         ["ignore_missing_references", False, None],
+                         ["execution_order", "variants-per-test",
+                          None]]:
+            act = args.get(scenario[0])
+            self.assertIn(act, scenario[1:],
+                          "args: Invalid value '%s' of key '%s' '%s'" % (
+                              act, scenario[0], scenario[1:]))
 
         # config
         conf_path = jobdata.retrieve_config(pth)
-        if os.path.exists(conf_path):
-            exp = "[avocado.selftest]\njobdata = yes"
-            with open(conf_path, "r") as conf:
-                act = conf.read()
-                if exp not in act:
-                    errs.append("config: Expected string\n%s\n\nNot in:\n%s"
-                                % (exp, act))
-
-        else:
-            errs.append("config: Retrieved path '%s' does not exists"
-                        % conf_path)
+        self.assertTrue(os.path.exists(conf_path),
+                        "config: Retrieved path '%s' does not exists" %
+                        conf_path)
+        exp = "[avocado.selftest]\njobdata = yes"
+        with open(conf_path, "r") as conf:
+            act = conf.read()
+            self.assertIn(exp, act,
+                          "config: Expected string\n%s\n\nNot in:\n%s" % (
+                              exp, act))
 
         # cmdline
         act = jobdata.retrieve_cmdline(pth)
         exp = ['/usr/local/bin/avocado', 'run', '--external-runner',
                '/bin/echo', '-m', 'examples/mux-0.yaml', '--', 'yes', 'no']
-        if exp != act:
-            errs.append("cmdline: Invalid cmdline '%s' (%s)" % (act, exp))
-        self.assertFalse(errs, "Errors: %s" % "\n  ".join(errs))
+        self.assertEqual(exp, act,
+                         "cmdline: Invalid cmdline '%s' (%s)" % (act, exp))
 
     @unittest.skipIf(PY3, "Skipping tests with data pickled on Python 2")
     def setUp(self):