By default, callouts aren’t allowed after DML operations in the same transaction because DML operations result in pending uncommitted work that prevents callouts from executing. Sometimes, you might want to insert test data in your test method using DML before making a callout. To enable this, enclose the portion of your code that performs the callout within Test.startTest and Test.stopTest statements. The Test.startTest statement must appear before the Test.setMock statement. Also, the calls to DML operations must not be part of the Test.startTest/Test.stopTest block.
DML operations that occur after mock callouts are allowed and don’t require any changes in test methods.
This example is based on the previous example. The example shows how to use Test.startTest and Test.stopTest statements to allow DML operations to be performed in a test method before mock callouts. The test method (testEchoString) first inserts a test account, calls Test.startTest, sets the mock callout mode using Test.setMock, calls a method that performs the callout, verifies the mock response values, and finally, calls Test.stopTest.
@isTest private class WebSvcCalloutTest { @isTest static void testEchoString() { // Perform some DML to insert test data Account testAcct = new Account('Test Account'); insert testAcct; // Call Test.startTest before performing callout // but after setting test data. Test.startTest(); // Set mock callout class Test.setMock(WebServiceMock.class, new WebServiceMockImpl()); // Call the method that invokes a callout String output = WebSvcCallout.callEchoString('Hello World!'); // Verify that a fake result is returned System.assertEquals('Mock response', output); Test.stopTest(); } }
Test.startTest();
MyClass.asyncCall();
Test.stopTest();
Test.setMock(..); // Takes two arguments
MyClass.mockCallout();
MyClass.asyncCall();
Test.startTest();
Test.setMock(..); // Takes two arguments
MyClass.mockCallout();
Test.stopTest();
Asynchronous calls that occur after mock callouts are allowed and don’t require any changes in test methods.