I've create a button to show all activities on lightining. It all works, but when I create the test class for the class, the code coverage of the class % remaing 0!

Here is the Class

public class ShowAllCaseActivity {
    
    Id caseId= ApexPages.currentPage().getParameters().get('Id');
 
public list <task> tasklist {get;set;}
    
public ShowAllCaseActivity(){
 
    if(caseId !=null ){
        
tasklist= [select id,Status,ActivityDate,Subject,Who.Name,What.Name,Description,LastModifiedDate,Owner.Name FROM Task WHERE WhatID=:caseId OR whoId=:caseId];
        
}
}
public PageReference cancel() {
    
PageReference ldPage = new PageReference('/'+caseId);
    
ldPage.setRedirect(true);
    
return ldPage;
}

}

and this is the test class...considering that I am still learning, I am pretty sure there is clearly something which I am missing:
 

@isTest
public class tstViewAllActivity {
    
static TestMethod void myShowAllCaseActivityTest()
  {
        Account acc = new Account();
            acc.Name ='TestAcc';
            insert acc;
        
            Contact cont = new Contact();
            cont.LastName ='Test';
            cont.accountId = acc.id;
            cont.Newsletter__c = 'false';
            cont.Email = 'test@test.ukic';
            cont.LeadSource = 'Email';
            cont.Source_Type__c = 'Salesforce';
            cont.Country_USE_ME__c = 'United Kingdom';
            cont.phone = '+44712345677';
            insert cont;

        Case caseObj = new Case();
        caseObj.Case_Reason__c = 'Couple';
        caseObj.Status = 'New';
        insert caseObj;

        
        Task myT = new Task();
        myT.Subject = 'Testme';
        myT.WhoId = cont.Id;
        myT.WhatId = caseObj.Id;
        myT.Status = 'Not Started'; 
        insert myT;
        }
        }