public class ListPaginationBase {
    
    public Integer listSize {get; set;}
    public Integer pageSize {get; set;}
    public Integer currentPageIndex {get; set;}
    public List<Object> fullList {get; set;}
  
    public void initializePagination(Integer listTotalSize, Integer singlePageSize) {
        fullList = new List<Object>();
        listSize = listTotalSize;
        pageSize = singlePageSize;
        currentPageIndex = 0;
    }
    
    public void initializePagination(List<Object> objectList, Integer singlePageSize) {
        fullList = ObjectList;
        listSize = fullList.size();
        pageSize = singlePageSize;
        currentPageIndex = 0;
    }
    
    public Integer getPageCount() {
        //Returns the number of pages required to show all data given a page limit
        //if page limit is not set or is equal to zero, then return 1; dont divide by zero
        //is empty list then return 1
        if (pageSize <= 0 || listSize <= 0)
            return 1;
        else
            return (Integer) Math.ceil((Decimal)listSize / (Decimal)pageSize);
    }
    
    public Boolean getHasNext() {
        //Returns true if the list has next pages
        return currentPageIndex < (getPageCount() - 1);
    }
    
    public Boolean getHasPrevious() {
        //Returns true if the list has previous pages
        return currentPageIndex > 0;
    }
    
    public Integer getfirstRowIndex() {
        //Returns the index of the first row to show in the PageBlockTable using the first attribute
        return currentPageIndex * pageSize;
    }
    
    public List<Object> getObjectPageList() {
        List<Object> returnList = new List<Object>();
        
        for(Integer index = getFirstRowIndex(); index < getFirstRowIndex() + pageSize; index++) {
            if (index < fullList.size()) {
                returnList.add(fullList.get(index));
            }
        }
        
        return returnList;
    }
    
    public PageReference firstAction() {   
        //Action fired when the user click the First Button
        //Set the Page Index to Zero
        if(getHasPrevious())
            currentPageIndex = 0;
        
        return null;
    }
    
    public PageReference lastAction() {
        //Action fired when the user click the Last Button
        //Set the Page Index to pages count - 1
        
        if(getHasNext())
            currentPageIndex = getPageCount() - 1;
        
        return null;
    }
    
    public PageReference nextAction() {
        //Action fired when the user click the Next Button
        //increment the current page index by 1
        if(getHasNext())
            currentPageIndex++;
        
        return null;
    }
    
    public PageReference previousAction() {
        //Action fired when the user click the Last Button
        //decrement the current page index by 1
        if(getHasPrevious())
            currentPageIndex--;
        
        return null;
    }
    
}

@isTest  (SeeAllData=true) 

    private class TESTAccountOpportunityTabExtension {
    
        static testmethod void AccountOpportunityTabExtension_Test (){
        
            test.StartTest();
        
            Account acc = new Account(Name ='icrm testing acc');
            insert acc;
            
            opportunity opp = new opportunity ( Name='testing DIE 4/6/2015' ,  AccountId= acc.Id,StageName = 'Prospecting', 
                               type= 'parts', Description= 'describe', Inconterms__c = 'FCA', CloseDate = System.today().addDays(30));
            
           insert opp;
           
           opportunity opps = new opportunity ( id = '0068E0000060EhbQAE', Name='testing DIE 4/6/2015' ,  AccountId= acc.Id,StageName = 'Prospecting', 
                               type= 'Sales', Opportunity_Division__c = 'PRODUCT SUPPORT', Description= 'describe', Inconterms__c = 'FCA',  CloseDate = System.today().addDays(30));
            
           update opps;
           
           opportunity Deltaopp = new opportunity ( id = '0068E000009BCivQAG', Name='testing DIE 4/6/2015' ,  AccountId= acc.Id,StageName = 'Prospecting', 
                               type= 'Sales', Opportunity_Division__c = 'POWER SYSTEM-DELTA(PERKINS)', Description= 'describe', Inconterms__c = 'FCA',  CloseDate = System.today().addDays(30));
            
           update Deltaopp;
           
           opportunity EnginePowerGenerationaopp = new opportunity ( id = '0068E000008Myy4QAC', Name='testing DIE 4/6/2015' ,  AccountId= acc.Id,StageName = 'Prospecting', 
                               type= 'Sales', Opportunity_Division__c = 'ENGINE POWER GENERATION', Description= 'describe', Inconterms__c = 'FCA',  CloseDate = System.today().addDays(30));
            
           update EnginePowerGenerationaopp ;
           
           opportunity Otheropp = new opportunity ( id = '0068E000009BDvgQAG', Name='testing DIE 4/6/2015' ,  AccountId= acc.Id,StageName = 'Prospecting', 
                               type= 'Sales', Opportunity_Division__c = 'OTHERS MISC - INTERNAL', Description= 'describe', Inconterms__c = 'FCA',  CloseDate = System.today().addDays(30));
            
           update Otheropp ;
           
    
           PageReference pref = Page.Opp_Tabs;
           pref.getParameters().put('id', acc.id);
           Test.setCurrentPage(pref);
           
           ApexPages.StandardController sc = new ApexPages.StandardController(acc);
           
           AccountOpportunityTabExtension mc = new AccountOpportunityTabExtension(sc);
          
           PageReference result = mc.NewOpp();
           System.assertNotEquals(null, result);

           PageReference result2 = mc.sortConstructionPaginationList();
           System.assertNotEquals(null, result); 
           
           PageReference result3 = mc.sortProductSupportPaginationList();
           System.assertNotEquals(null, result); 
           
           PageReference result4 = mc.sortPowerSystemPaginationList();
           System.assertNotEquals(null, result); 
           
           PageReference result5 = mc.sortDeltaPaginationList();
           System.assertNotEquals(null, result); 
           
           PageReference result6 = mc.sortOtherPaginationList();
           System.assertNotEquals(null, result);  

           test.stopTest();         
        }
        
}