tests/acceptance/migration: Test EXEC transport when migrating

Along with VM migration via TCP, we can use migration through
the EXEC transport protocol

Signed-off-by: Oksana Vohchana <ovoshcha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200203111631.18796-3-ovoshcha@redhat.com>
[PMD: Split patch in 2, reworded subject and description]
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>

tests/acceptance/migration.py

@@ -12,9 +12,11 @@
 
 import tempfile
 from avocado_qemu import Test
+from avocado import skipUnless
 
 from avocado.utils import network
 from avocado.utils import wait
+from avocado.utils.path import find_command
 
 
 class Migration(Test):
@@ -60,3 +62,11 @@ def test_migration_with_unix(self):
         with tempfile.TemporaryDirectory(prefix='socket_') as socket_path:
             dest_uri = 'unix:%s/qemu-test.sock' % socket_path
             self.do_migrate(dest_uri)
+
+    @skipUnless(find_command('nc', default=False), "'nc' command not found")
+    def test_migration_with_exec(self):
+        """
+        The test works for both netcat-traditional and netcat-openbsd packages
+        """
+        free_port = self._get_free_port()
+        dest_uri = 'exec:nc -l localhost %u' % free_port