Unit test exceptions raised duing live migration monitoring

This adds some test coverage to verify the expected handling of
exceptions raised in Guest.get_job_info() during live migration
monitoring.

In the case of the related bug fix, this testing verifies that the post
live migration method is called after handling the special case and
workaround of libvirt error "migration was active, but no RAM info was
set".

Related-Bug: #1982284

Change-Id: Ibab54aa4f2e929b384b75e7e0a21c8b059b680c5

1 files changed, 79 insertions, 0 deletions

diff --git a/nova/tests/unit/virt/libvirt/test_driver.py b/nova/tests/unit/virt/libvirt/test_driver.py
index e8876ec7b6..442d852346 100644
--- a/nova/tests/unit/virt/libvirt/test_driver.py
+++ b/nova/tests/unit/virt/libvirt/test_driver.py
@@ -13688,6 +13688,85 @@ class LibvirtConnTestCase(test.NoDBTestCase,
     def test_live_migration_main_monitoring_failed(self):
         self._test_live_migration_main(mon_side_effect=Exception)
 
+    @mock.patch.object(host.Host, "get_connection", new=mock.Mock())
+    @mock.patch.object(utils, "spawn", new=mock.Mock())
+    @mock.patch.object(host.Host, "get_guest")
+    @mock.patch.object(
+        libvirt_driver.LibvirtDriver, "_live_migration_copy_disk_paths")
+    def _test_live_migration_monitor_job_stats_exception(
+        self, exc, mock_copy_disk_paths, mock_get_guest, expect_success=True
+    ):
+        # Verify behavior when various exceptions are raised inside of
+        # Guest.get_job_info() during live migration monitoring.
+        mock_domain = mock.Mock(fakelibvirt.virDomain)
+        guest = libvirt_guest.Guest(mock_domain)
+        mock_get_guest.return_value = guest
+
+        # First, raise the exception from jobStats(), then return "completed"
+        # to make sure we exit the monitoring loop.
+        guest._domain.jobStats.side_effect = [
+            exc,
+            {'type': fakelibvirt.VIR_DOMAIN_JOB_COMPLETED},
+        ]
+
+        drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
+        instance = objects.Instance(**self.test_instance)
+        post_method = mock.Mock()
+        migrate_data = mock.Mock()
+        disks_to_copy = (['/some/path/one', '/test/path/two'],
+                         ['vda', 'vdb'])
+        mock_copy_disk_paths.return_value = disks_to_copy
+
+        func = drvr._live_migration
+        args = (self.context, instance, mock.sentinel.dest, post_method,
+                mock.sentinel.recover_method, mock.sentinel.block_migration,
+                migrate_data)
+
+        if expect_success:
+            func(*args)
+            post_method.assert_called_once_with(
+                self.context, instance, mock.sentinel.dest,
+                mock.sentinel.block_migration, migrate_data
+            )
+        else:
+            actual_exc = self.assertRaises(
+                fakelibvirt.libvirtError, func, *args)
+            self.assertEqual(exc, actual_exc)
+
+    def test_live_migration_monitor_job_stats_no_domain(self):
+        exp = fakelibvirt.make_libvirtError(
+            fakelibvirt.libvirtError, 'no domain',
+            error_code=fakelibvirt.VIR_ERR_NO_DOMAIN
+        )
+        self._test_live_migration_monitor_job_stats_exception(
+            exp, expect_success=True)
+
+    def test_live_migration_monitor_job_stats_op_invalid(self):
+        exp = fakelibvirt.make_libvirtError(
+            fakelibvirt.libvirtError, 'operation invalid',
+            error_code=fakelibvirt.VIR_ERR_OPERATION_INVALID
+        )
+        self._test_live_migration_monitor_job_stats_exception(
+            exp, expect_success=True)
+
+    def test_live_migration_monitor_job_stats_no_ram_info_set(self):
+        exp = fakelibvirt.make_libvirtError(
+            fakelibvirt.libvirtError, 'internal error',
+            error_message='migration was active, but no RAM info was set',
+            error_code=fakelibvirt.VIR_ERR_INTERNAL_ERROR
+        )
+        self._test_live_migration_monitor_job_stats_exception(
+            exp, expect_success=True)
+
+    def test_live_migration_monitor_job_stats_internal_error(self):
+        exp = fakelibvirt.make_libvirtError(
+            fakelibvirt.libvirtError,
+            'some other internal error',
+            error_code=fakelibvirt.VIR_ERR_INTERNAL_ERROR
+        )
+        self._test_live_migration_monitor_job_stats_exception(
+            exp, expect_success=False)
+
     @mock.patch('os.path.exists', return_value=False)
     @mock.patch('nova.virt.libvirt.utils.create_image')
     @mock.patch.object(libvirt_driver.LibvirtDriver,