Hi..

I'm having error like this.. so I'm not getting any code coverage..
Class.AssetParts.<init>: line 10, column 1
Class.AssetPartsTestClass.AssetPartsTestClass: line 26, column 1

Apex Class:

public with sharing class AssetParts {
  public Asset_Part__c astpart;
  public Physical_Asset__c asset{get;set;}
  public string assetname;
    public AssetParts(ApexPages.StandardController con)
    {
        astpart=(Asset_Part__c)con.getRecord();
        String astname = ApexPages.currentPage().getParameters().get('retURL');
        string[] strsplit = astname.split('/');
        assetname = strsplit[1];---------------> here class error
         asset= new Physical_Asset__c();
       
           
    }
    public String errmsg{get;set;}
    public PageReference Save()
    {
            astpart.Asset_Name__c =assetname;
            insert astpart;
                           
            PageReference ref= new PageReference('/'+assetname);
            ref.setredirect(true);
            return ref;
        }
    }  
   My test class is:

@isTest
public class AssetPartsTestClass
{
     static TestMethod void AssetPartsTestClass()
    {
      PageReference ref = Page.AssetParts;
      Test.setcurrentPage(ref);
     
     
      Account testAccount = new Account(Name='Test Company Name');
      insert testAccount;
    
      Physical_Asset__c phy = new Physical_Asset__c(Name='Physical Asset Name',Vendor_Account__c=testAccount.id);
      insert phy;
     
      Asset_Part__c testassetpart = new Asset_Part__c(Name='Test Assetpart Name',Vendor_Account__c=testAccount.id,Asset_Name__c =phy.id);
      insert testassetpart;
     
        
     
      ApexPages.currentPage().getParameters().put('assetname',phy.id);
      ApexPages.StandardController sc = new ApexPages.StandardController(testassetpart);     
    
      AssetParts  ap = new AssetParts(sc);---------->test class error
      ap.save();
          
    }
}


Please help me from this..