Fixed #6350, Solid gauge series did not have CSS point class.

js/modules/solid-gauge.src.js

@@ -299,7 +299,7 @@ H.seriesType('solidgauge', 'gauge', {
 				}
 			} else {
 				point.graphic = renderer.arc(shapeArgs)
-					.addClass('highcharts-point')
+					.addClass(point.getClassName(), true)
 					.attr({
 						fill: toColor,
 						'sweep-flag': 0

samples/unit-tests/series-solidgauge/solidgauge-styled-series/demo.details

@@ -0,0 +1,6 @@
+---
+ resources:
+   - https://code.jquery.com/qunit/qunit-2.0.1.js
+   - https://code.jquery.com/qunit/qunit-2.0.1.css
+ js_wrap: b
+...

samples/unit-tests/series-solidgauge/solidgauge-styled-series/demo.html

@@ -0,0 +1,11 @@
+<script src="https://code.highcharts.com/js/highcharts.js"></script>
+<script src="https://code.highcharts.com/js/highcharts-more.js"></script>
+<script src="https://code.highcharts.com/js/modules/solid-gauge.js"></script>
+<style>
+	@import 'https://code.highcharts.com/css/highcharts.css';
+</style>
+
+<div id="qunit"></div>
+<div id="qunit-fixture"></div>
+
+<div id="container" style="width: 600px; margin: 0 auto"></div>

samples/unit-tests/series-solidgauge/solidgauge-styled-series/demo.js

@@ -0,0 +1,74 @@
+QUnit.test('Solid gauge styled series color (#6350)', function (assert) {
+
+    var gaugeOptions = {
+        chart: {
+            type: 'solidgauge',
+            animation: false
+        },
+
+        title: null,
+
+        tooltip: {
+            enabled: false
+        },
+
+        pane: {
+            center: ['50%', '85%'],
+            size: '140%',
+            startAngle: -90,
+            endAngle: 90,
+            background: {
+              backgroundColor: (Highcharts.theme && Highcharts.theme.background2) || '#EEE',
+              innerRadius: '60%',
+              outerRadius: '100%',
+              shape: 'arc'
+            }
+        },
+
+        // the value axis
+        yAxis: {
+            stops: [
+                [0, '#00ff00'],
+                [1, '#00ff00']
+            ],
+            lineWidth: 0,
+            minorTickInterval: null,
+            tickAmount: 2,
+            title: {
+                y: -70
+            },
+            labels: {
+                y: 16
+            }
+        },
+
+        plotOptions: {
+            solidgauge: {
+                dataLabels: {
+                    y: 5,
+                    borderWidth: 0,
+                    useHTML: true
+                },
+                animation: false
+            }
+        }
+    };
+
+    // The speed gauge
+    var chart = Highcharts.chart('container', Highcharts.merge(gaugeOptions, {
+        yAxis: {
+          min: 0,
+          max: 200
+        },
+        series: [{
+          data: [80]
+        }]
+    }));
+
+    assert.strictEqual(
+        chart.series[0].data[0].graphic.element.className.baseVal,
+        'highcharts-point highcharts-color-0',
+        'color classes are applied.'
+    );
+
+});