QUnit.test(
    '#9233: data labels should be displayed for visible null points.',
    function (assert) {
        var chart = Highcharts.chart('container', {
            series: [
                {
                    type: 'heatmap',
                    data: [[0, 0, null]],
                    dataLabels: {
                        enabled: true,
                        nullFormat: 'N/A'
                    }
                }
            ]
        });

        assert.ok(
            chart.series[0].points[0].dataLabel,
            'Data label created for null point.'
        );
    }
);
