[SalesForce] Need Explanation – Too Many DML Rows: 10001

Your unit tests should not be operating on data which exists in your production org.

If the receiving_Tests class is annotated with @seeAllData=true, switch it to false and then create all of the data that you need for the test within the test itself.

If the receiving_Tests class has an API version earlier than v24, you should modify it to v24 or later, make any other corrections to the tests so that it passes all tests and deploy it to production as well.

This looks to be a good opportunity for you to test your Large Data Volume performance by creating more than 10,000 records in the setup for your test and ensuring that the test is successfully executed in the sandbox.

Isolation of Test Data from Organization Data in Unit Tests

The reason for your limit exception is probably that you're trying to do to many operations in one transaction.

You need to know that all governor limits are counted against one transaction. Transaction is not one class execution - it is the whole stack of calls.

Example:

• You insert opportunity // Transaction begins
• beforeInsert trigger is executed (let's say it has 1 SOQL query inside - limit of soql for transaction equals 1 right now)
• afterInsert trigger is executed (let's say it has 2 SQOL and update of related record - Account)
• account beforeInsert is executed...
• account afterInsert
• End of transaction (success if no error, and governor limits are not exceeded)

So if you have your test class - in one method you're making multiple inserts - it's all counted as one transaction.

Best practice for test class development is to separate it to multiple methods - each testing one thing. This way each test method is executed separately and have separate governor limits. Also good practice is to include method with @testSetup method when you will insert all records required for other test methods.

@isTest
public class WE_OppUpdatesTest {

   @testSetup
   static void dataSetup() {
      ...
      insert user;
   }

   static void additionalDataSetup() {
      User u = [SELECT Id FROM User WHERE Name = 'yourname' LIMIT 1];
      System.runAs(u) {
         ... insert all additional records
      }
   }

   static testMethod void test_something() {
      additionalDataSetup();
      ...
   }

   static testMethod void test_somethingElse() {
      additionalDataSetup();
      ...
   }
}

Hope this helps.