How to test Salesforce Embedded Service Chat Code?

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openSubtab() for Lightning Experience in Salesforce

Sample Code:Aura Component:<aura:component implements="flexipage:availableForAllPageTypes" access="global" >        <lightning:workspaceAPI aura:id="workspace" />    <lightning:button label="Open Tab with Subtab" onclick="{! c.openTabWithSubtab }" />     </aura:component> JavaScript Controller:({        openTabWithSubtab : function(component, event, helper) {                var ....