How to use the puppetboard.utils.get_db_version function in puppetboard

def test_db_version_good(mocker, mock_info_log):
    mocker.patch.object(app.puppetdb, 'current_version', return_value='4.2.0')
    err = 'PuppetDB Version %d.%d.%d' % (4, 2, 0)
    result = utils.get_db_version(app.puppetdb)
    mock_info_log.assert_called_with(err)
    assert (4, 0, 0) < result
    assert (4, 2, 0) == result
    assert (3, 2, 0) < result
    assert (4, 3, 0) > result
    assert (5, 0, 0) > result
    assert (4, 2, 1) > result

def test_db_invalid_version(mocker, mock_err_log):
    mocker.patch.object(app.puppetdb, 'current_version', return_value='4')
    err = u"Unable to determine version from string: '%s'" % (4)
    result = utils.get_db_version(app.puppetdb)
    mock_err_log.assert_called_with(err)
    assert (4, 0, 0) < result
    assert (4, 2, 0) == result

def test_db_http_error(mocker, mock_err_log):
    err = "NotFound"

    def raise_http_error():
        x = Response()
        x.status_code = 404
        x.reason = err
        raise HTTPError(err, response=x)

    mocker.patch.object(app.puppetdb, 'current_version',
                        side_effect=raise_http_error)
    result = utils.get_db_version(app.puppetdb)
    mock_err_log.assert_called_with(err)
    assert result == ()

def test_db_empty_response(mocker, mock_err_log):
    err = "Empty Response"

    def connection_error():
        raise EmptyResponseError(err)

    mocker.patch.object(app.puppetdb, 'current_version',
                        side_effect=connection_error)
    result = utils.get_db_version(app.puppetdb)
    mock_err_log.assert_called_with(err)
    assert result == ()

def test_db_connection_error(mocker, mock_err_log):
    err = "ConnectionError"

    def connection_error():
        x = Response()
        x.status_code = 500
        x.reason = err
        raise ConnectionError(err, response=x)

    mocker.patch.object(app.puppetdb, 'current_version',
                        side_effect=connection_error)
    result = utils.get_db_version(app.puppetdb)
    mock_err_log.assert_called_with(err)
    assert result == ()

envs = environments()
    metrics = {
        'num_nodes': 0,
        'num_resources': 0,
        'avg_resources_node': 0}
    check_env(env, envs)

    if env == '*':
        query = app.config['OVERVIEW_FILTER']

        prefix = 'puppetlabs.puppetdb.population'
        query_type = ''

        # Puppet DB version changed the query format from 3.2.0
        # to 4.0 when querying mbeans
        if get_db_version(puppetdb) < (4, 0, 0):
            query_type = 'type=default,'

        num_nodes = get_or_abort(
            puppetdb.metric,
            "{0}{1}".format(prefix, ':%sname=num-nodes' % query_type))
        num_resources = get_or_abort(
            puppetdb.metric,
            "{0}{1}".format(prefix, ':%sname=num-resources' % query_type))
        avg_resources_node = get_or_abort(
            puppetdb.metric,
            "{0}{1}".format(prefix,
                            ':%sname=avg-resources-per-node' % query_type))
        metrics['num_nodes'] = num_nodes['Value']
        metrics['num_resources'] = num_resources['Value']
        metrics['avg_resources_node'] = "{0:10.0f}".format(
            avg_resources_node['Value'])

def radiator(env):
    """This view generates a simplified monitoring page
    akin to the radiator view in puppet dashboard
    """
    envs = environments()
    check_env(env, envs)

    if env == '*':
        query_type = ''
        if get_db_version(puppetdb) < (4, 0, 0):
            query_type = 'type=default,'
        query = None
        metrics = get_or_abort(
            puppetdb.metric,
            'puppetlabs.puppetdb.population:%sname=num-nodes' % query_type)
        num_nodes = metrics['Value']
    else:
        query = AndOperator()
        metric_query = ExtractOperator()

        query.add(EqualsOperator("catalog_environment", env))
        metric_query.add_field(FunctionOperator('count'))
        metric_query.add_query(query)

        metrics = get_or_abort(
            puppetdb._query,