'get_volume_stats must fill the correct values.'

def test_get_volume_stats(self):

    self._set_driver()
    drv = self._driver
    drv._mounted_shares = [self.TEST_NFS_EXPORT1, self.TEST_NFS_EXPORT2]
    with mock.patch.object(drv, '_ensure_shares_mounted') as mock_ensure_share:
        with mock.patch.object(drv, '_get_capacity_info') as mock_get_capacity_info:
            mock_get_capacity_info.side_effect = [((10 * units.Gi), (2 * units.Gi), (2 * units.Gi)), ((20 * units.Gi), (3 * units.Gi), (3 * units.Gi))]
            drv._ensure_shares_mounted()
            drv.get_volume_stats()
            calls = [mock.call(self.TEST_NFS_EXPORT1), mock.call(self.TEST_NFS_EXPORT2)]
            mock_get_capacity_info.assert_has_calls(calls)
            self.assertTrue(mock_ensure_share.called)
            self.assertEqual(30.0, drv._stats['total_capacity_gb'])
            self.assertEqual(5.0, drv._stats['free_capacity_gb'])
            self.assertEqual(5, drv._stats['reserved_percentage'])
            self.assertTrue(drv._stats['sparse_copy_volume'])
