Highcharts function not covered with unit tests with Karma + Jasmine - highcharts

Question

Since I'm trying to use your Highcharts package, I'm facing an issue when unit testing the component that use Highcharts function.
Here is my context:
I have a component (the only one) that use Highcharts. In the Web client, When I run unit test on this component, chart function legendItemClick not getting covered.
Code below are the Javascript transpilled code. Here is my original typescript file:
let dsCapacityChartOptions = {
chart: {
type: 'pie',
spacing: [0, 10, 2, 10],
margin: [-10, 0, 30, 0]
},
title: {
text: ''
},
credits: {
enabled: false
},
plotOptions: {
pie: {
shadow: false,
colors: ['#3E7BBF', '#CBCBCB', '#92B2D9'],
point: {
events: {
legendItemClick: function () {
return false;
}
}
}
},
series: {
states: {
hover: {
enabled: false
},
inactive: {
opacity: 1
}
}
}
},
tooltip: {
outside: true,
style: {
color: '#000000',
opacity: 1,
fontSize: '12px',
fontFamily: 'Metropolis,Avenir Next,Helvetica Neue,Arial,sans-serif'
},
formatter:
function () {
return '<b>' + this.point.x + '</b>: ' + this.point.formattedCapacity + " (" + this.percentage.toFixed(2) + "%)";
}
},
series: [{
type: 'pie',
name: this.labelsObj["vsc.portlet.dsCapacity.label"],
size: '80%',
innerSize: '70%',
showInLegend: true,
dataLabels: {
enabled: false
},
data: []
}],
legend: {
labelFormatter: function () {
return this.x + ": " + this.formattedCapacity;
},
align: 'center',
layout: 'vertical',
itemStyle: {
color: '#454545',
fontWeight: '500',
fontSize: '12px',
fontFamily: 'Metropolis,Avenir Next,Helvetica Neue,Arial,sans-serif'
},
itemHoverStyle: {
color: '#454545',
cursor: 'default'
}
},
exporting: { enabled: false }
};
Here is what I'm doing to make the unit tests works-
it('should call legendItemClick', () => {
let spy = spyOn(component.dsCapacityChartOptions.plotOptions.pie.point.events, 'legendItemClick')
component.dsCapacityChartOptions.plotOptions.pie.point.events.legendItemClick();
expect(spy).toHaveBeenCalledTimes(1);
})
Highcharts function not covered with unit tests with Karma + Jasmine
Please find below snippet of code coverage-
Code coverage

Answer 1

Your unit test doesn't make sense. You explicitly invoke a function and test if it was really called. In your case, legendItemClick returns a value, hence you should check the result of the call. There's no need to use a spy.
The test would then look simple as follows:
it('#legendItemClick should return false', () => {
const result = component.dsCapacityChartOptions.plotOptions.pie.point.events.legendItemClick();
expect(result).toBe(false);
})