Hi All, 

I've amended a solution for tracking page views I found here:
https://success.salesforce.com/answers?id=9063A000000Dq6MQAS

I'm using it to track who has viewed an Opportunity record page - however I have no idea where to start with the test class - I'm currently working through a couple of trailhead modules, though any pointers would be greatly appreciated

Thanks

Terri 
 

public without sharing class lastViewedOpportunity{
    public Datetime cDT;
    public String LongDate;
    public String firstname;
    public String lastname;
    public String existinglastviewed;
    public String userid;
    private final Opportunity opp;
    
    public lastViewedOpportunity(ApexPages.StandardController stdController) {
        this.opp = (Opportunity)stdController.getRecord();
    }
    
    public String getLongDate() {
        cDT = System.now();
        //Formats the datetime value to locale
        LongDate = cDT.format('dd/MM/yyyy HH:mm');
        return LongDate;
    }
    
    
    public void updateField() {
        //Get the user info from the current user
        firstname = System.Userinfo.getFirstName();
        lastname = System.Userinfo.getLastName();
        userid = System.Userinfo.getUserId();
        //Get the Opportunity record to be updated
        Opportunity o = [select Last_Viewed_By__c, Track_Record__c from Opportunity where id = :opp.id limit 1];
        //get existing string of the record, so that new view can be appended to the end of this
        existinglastviewed = o.Last_Viewed_By__c;
        //check to see if the Opportunity has been flagged for tracking
        if(o.Track_Record__c){
            //Assign values to Last Viewed By field and update the record - only concatenate if there is a value there already
            if(existinglastviewed != null){
                o.Last_Viewed_By__c = (existinglastviewed + '; \n' + firstname + ' ' + lastname + ' ' + getLongDate());
            }
            else o.Last_Viewed_By__c = (firstname + ' ' + lastname + ' ' + getLongDate());
            update o;
        }    
    }
    
}