selftests: Add avocado -v selftest

This check "avocado -v" produces correct output and returns 0.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

selftests/functional/test_basic.py

@@ -8,6 +8,7 @@ import xml.dom.minidom
 import glob
 import aexpect
 import signal
+import re
 
 if sys.version_info[:2] == (2, 6):
     import unittest2 as unittest
@@ -55,6 +56,13 @@ class RunnerOperationTest(unittest.TestCase):
     def setUp(self):
         self.tmpdir = tempfile.mkdtemp(prefix='avocado_' + __name__)
 
+    def test_show_version(self):
+        result = process.run('./scripts/avocado -v', ignore_status=True)
+        self.assertEqual(result.exit_status, 0)
+        self.assertTrue(re.match(r"^Avocado \d+\.\d+\.\d+$", result.stderr),
+                        "Version string does not match 'Avocado \\d\\.\\d\\.\\"
+                        "d':\n%r" % (result.stderr))
+
     def test_runner_all_ok(self):
         os.chdir(basedir)
         cmd_line = './scripts/avocado run --sysinfo=off --job-results-dir %s passtest passtest' % self.tmpdir