@isTest static void testAccountUpdate() { Account acct = new Account({Name = 'Test'); acct.Integration Updated_c = false; insert acct; CalloutUtil.sendAccountUpdate (acct.Id); Account acctAfter = [SELECT Id, Integration Updated_c FROM Account WHERE Id = :acct.Id] [0]; System.assert(true, acctAfter.Integration_Updated_c); } The test method above calls a web service that updates an external system with Account information and sets the Account's Integration_Updated__c checkbox to True when it completes. The test fails to execute and exits with an error: "Methods defined as TestMethod do not support Web service callouts." What is the optimal way to fix this?