HI all,

I've just spent the last four hours attempting to write and test my first trigger.  We have a custom object Health Check that has a Master-Detail relationship to Accounts.  We instantiate a new HC record ~3 months.  We want to copy the notes from the previous HC to the new one.  I have taken a clicks & code approach to this. I am looking for hope on my code, but if there is a better way to approach this whole effort, I'm certainly open.

On the Health Checks object, I have a "Date Conducted" field and a rich text field (I know, but my users insisted) called "Health Check Notes." I also have an Account__c field, which contains the parent Account's ID.

On Accounts, I have a "Last Health Check Conducted" field and a "Health Check Notes" field (also a RTF).

I have a WFR that fires when a new Health Check is created or edited.  If "Date Conducted" >= "Last Health Check Conducted" (also covers my users editing their notes after the call as issues are resolved), I copy the contents of the Health Check Notes field from the child Health Check object to the parent Account.  That's tested and working.

Next, when a new HC is created, I need to copy the contents from the parent Account into the new HC record.  Since WFR won't go parent->child, I did some research and wrote a trigger:

trigger populateHealthCheckNotes on Health_Check__c (after insert){
  
    Map<Id,Account> accounts = new Map<Id,Account>
    ([select ID, Health_Check_Notes__c from Account where Id IN :trigger.newMap.keySet()]);
  
    for(Health_Check__c hc : trigger.new){
         if(hc.Account__c != null){
         hc.Health_Check_Notes__c = accounts.get(hc.Account__c).Health_Check_Notes__c;    
          }
    }   
 
}

I wrote a Test Class to go with this:

@isTest 
private class testPopulateHealthCheckNotesTrigger {
  static testMethod void testNotePopulation()  {
    Account testAccount = new Account(Health_Check_Notes__c = 'Negotiating',Name = 'test Name');
    insert testAccount;
    Health_Check__c testHealthCheck = new Health_Check__c(Account__c = testAccount.ID);

Test.startTest();
insert testHealthCheck;
Test.stopTest();
system.assert(testHealthCheck.Health_Check_Notes__c == testAccount.Health_Check_Notes__c);
}

}

However, I'm getting this error:

Time Started 6/25/2013 11:52 AM Class testPopulateHealthCheckNotesTrigger Method Name testNotePopulation Pass/Fail Fail Error Message System.DmlException: Insert failed. First exception on row 0; first error: CANNOT_INSERT_UPDATE_ACTIVATE_ENTITY, populateHealthCheckNotes: execution of AfterInsert

caused by: System.NullPointerException: Attempt to de-reference a null object

Trigger.populateHealthCheckNotes: line 8, column 1: [] Stack Trace Class.testPopulateHealthCheckNotesTrigger.testNotePopulation: line 9, column 1

I'm pretty sure I'm doing something wrong and it has to do with grabbing the account ID and making sure I'm copying the right information, but I'm not sure where/how I'm going wrong exactly.  I need this to work, as I have a similar copy-and-paste exercise to do with two other fields, but trying to start small and stay on sure footing here.

All help greatly appreciated.