/

Trigger code

trigger AddOwnerColor on Account (before insert, before update) {

// create a set of all the unique ownerIds
Set<Id> ownerIds = new Set<Id>();
for (Account a : Trigger.new)
  ownerIds.add(a.OwnerId);

// query for all the User records for the unique userIds in the records
// create a map for a lookup / hash table for the user info
Map<Id, User> owners = new Map<Id, User>([Select UserFavColor__c from User Where Id in :ownerIds]);

// iterate over the list of records being processed in the trigger and
// set the color before being inserted or updated
for (Account a : Trigger.new)
  a.Owner_Favorite_Color__c = owners.get(a.OwnerId).UserFavColor__c;

}

########################Test Classes##############################

@isTest
private class TestAccountColorTrigger {

static testMethod void testBulkInsert() {

  List<Account> accounts = new List<Account>();

  Profile p = [select id from profile where name='Marketing User'];
  // create a user to run the test as
  User u = new User(alias = 'test123', email='test1234@noemail.com',
         emailencodingkey='UTF-8', lastname='Testing1', languagelocalekey='en_US',
      localesidkey='en_US', profileid = p.Id, country='United States',
      UserFavColor__c='Buttercup Yellow',
      timezonesidkey='America/Los_Angeles', username='test1234@noemail.com');
  insert u;

  Profile p1 = [select id from profile where name='Standard User'];
  // create a user to own the account
  User u1 = new User(alias = 'test123', email='test12345@noemail.com',
      emailencodingkey='UTF-8', lastname='Testing', languagelocalekey='en_US',
      localesidkey='en_US', profileid = p1.Id, country='United States',
      UserFavColor__c='Pretty Pink',
      timezonesidkey='America/Los_Angeles', username='test12354@noemail.com');
  insert u1;

  // add 200 accounts to the list to be inserted
  for (Integer i=0;i<200;i++) {

      Account a = new Account(
          Name = 'Test Account',
          OwnerId = u1.Id
      );
      accounts.add(a);

  }

  // Switch to the runtime context
  Test.startTest();

  // run as a different user to test security and rights
  System.runAs(u) {
      insert accounts;
 }

  // Switch back to the original context
  Test.stopTest();

  // query for all accounts created and assert that the color was added correctly
  for (Account acct : [Select Owner_Favorite_Color__c from Account Where OwnerId = :u1.Id])
      System.assertEquals(acct.Owner_Favorite_Color__c,'Pretty Pink');

}
}