Its been a long time since I've had to write a test class and I'm a little rusty.  I'm getting this error 
Compile Error: Constructor not defined: [ApexPages.StandardController].<Constructor>(List<Subscription_Assets__c>) at line 32 column 37 

on this line: ApexPages.StandardController con2 = new ApexPages.StandardController(newasset);

I've also tried changing newasset to newsub and still get the same error.

Any help would be greatly appreciated

@isTest 
private class MultiAdTest{
 
static testMethod void MultiAdTest(){

}
static testMethod void MultiAdTest_test() {

       Account testAccount = new Account(Name = 'Test Account');
       insert testAccount;

Support_Subscription__c sub = new Support_Subscription__c(
                                    Dealer_Name__c = testAccount.Id,
                                    Subscription_Start_Date__c = Date.today(),
                                    of_Months__c = 12,
                                    Date_Received__c = Date.today(),
                                    Date_Received_Executed__c = Date.today(),
                                    Subscription_Status__c = 'Active',
                                    Dealer_Sales_Person__c = 'Mike Gray',
                                    Software_End_User_Agreement_Version_Date__c = Date.today());
insert sub;

//create an asset Record
List<Subscription_Assets__c> newasset = new List<Subscription_Assets__c>();
        Subscription_Assets__c asset = new Subscription_Assets__c(Support_Subscription__c = sub.Id);
        insert asset;
        newasset.add(asset);
          
    
Test.startTest();

ApexPages.StandardController con2 = new ApexPages.StandardController(newasset);
MultiAd controller = new MultiAd(con2);
controller.addlic();

PageReference testPage = Page.LicenseSummaryHomePage;
Test.setCurrentPage(testPage);

Test.stopTest();


}

}

 

/*
Class/Method Name: MultiAd
Description: Created Subscription Assets related to Support Subscription
Author/Date: Staci Gilmore 5/27/2020
*/


public with sharing class MultiAd { 
private final Subscription_Assets__c ln; 
Public string ss;
public List<AccountWrapper> wrappers{get;set;}
private Integer nextIdent=0;

public MultiAd(ApexPages.StandardController controller) { 

ss = ApexPages.CurrentPage().getparameters().get('id');

wrappers=new List<AccountWrapper>();
for(Integer idx=0; idx<1; idx++)
{
    wrappers.add(new AccountWrapper(nextIdent++));
}

} 




public List<Subscription_Assets__c> addlic {get; set;} 
  

public PageReference Save()
{
    List<Subscription_Assets__c> addlic=new List<Subscription_Assets__c>();
    Support_Subscription__c ssid = [select id, Name, RecordTypeID from Support_Subscription__c where id=:ss];
    for(AccountWrapper wrap:wrappers)
    {
       Subscription_Assets__c lic =wrap.asset;
       lic.Support_Subscription__c = ssid.id;
       lic.Support_Subscription_Record_Type__c = ssid.recordTypeID;
       addlic.add(lic);
    }
        
    insert addlic;
          
    PageReference pageRef = new PageReference(ApexPages.currentPage().getUrl());
    pageRef.setRedirect(true);
    return pageRef;      
    
}

public class AccountWrapper
{
    public Subscription_Assets__c asset{get; private set;}
    public Integer ident{get; private set;}
    
    
    public AccountWrapper(Integer inIdent)
    {
        ident=inIdent;
        asset=new Subscription_Assets__c();
            
    }
}         
}