Good morning everyone,  

I have a trigger that will assign a lookup value from a custom object (data_center_location__c) to an Opportunity based on a picklist field (location__c) on the Opportunity.  The trigger works okay, but i'm having trouble with my test class.  I'm receiving the Expression error when trying to save.  I also have to state that i'm not a developer so I don't have a great understanding of basic concepts when it comes to test classes:

Trigger is:

trigger UpdateDataCenterLocation on Opportunity (before insert, before update){
      Set<String> locationSet = new Set<String>();
      Map<String,Id> mapLocationSetwithDataCntr = new Map<String,Id>();
      for (Opportunity obj: trigger.new){
          if(!String.isBlank(obj.Location__c)){
              locationSet.add(obj.Location__c);
          }
      }
      if(!locationSet.isEmpty()){
          for(Data_Center_Location__c dataCenter : [SELECT Id,Opportunity_Location_Code__c FROM Data_Center_Location__c WHERE Opportunity_Location_Code__c IN :locationSet]){
              mapLocationSetwithDataCntr.put(dataCenter.Opportunity_Location_Code__c,dataCenter.Id);//Expecting there will be one record for each location, otherwise this map will have last Data_Center_Location__c Id
          }
      }
      for (Opportunity obj: trigger.new){
          if(!String.isBlank(obj.Location__c) && mapLocationSetwithDataCntr != null && mapLocationSetwithDataCntr.get(obj.Location__c) != null){
                  obj.Data_Center_Location__c = mapLocationSetwithDataCntr.get(obj.Location__c);
        }
          else{
              obj.Data_Center_Location__c = null;
          }
      }
  }

________
Again, the trigger works as should, the test class on the other hand doesn't:

@isTest

    Private class UpdateDataCenterLocationTestClass {
        static testMethod void UpdateDataCenterLocation () {
    
        List <Opportunity> OpportunityLst = new List <Opportunity>();
        Opportunity Opp = new Opportunity ();
       Opportunity.Name = 'test Opportunity';
       Opportunity.Location__c = 'TX-DAL-03LEW' ;
       Opportunity.Stagename = 'Stage 1: Qualified Prospect';
       
       Opportunity.Closedate = '2015, 2, 26';
        OpportunityLst.add(opp);
        
        insert Opp;
    
    }
    }

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For the test class, i'm just trying to create an Opportunity with the location__c field populated with a value, seems easy enough.  Any guidance would be much appreciated.

Thanks everyone
-d