I'm getting an error "No Apex class named 'AnimalLocatorMock' was found" when validating the challenge. However, everything seems to be coded correctly, and I have 100 percent code coverage on the AnimalLocator class. I have no idea what's wrong with my test classes. Does anyone have any ideas about what code be wrong?@IsTestprivate class AnimalLocatorTest { @isTest static void testGetCallout() { // Set mock callout class Test.setMock(HttpCalloutMock.class, new AnimalLocatorMock()); // This causes a fake response to be sent // from the class that implements HttpCalloutMock. String animalname = AnimalLocator.getAnimalNameById(2); // Verify that the response received contains fake values String expectedValue = 'bear'; System.assertEquals(animalname, expectedValue); }}@IsTestglobal class AnimalLocatorMock implements HttpCalloutMock { //Implement this interface method global HTTPResponse respond(HTTPRequest request) { // Create a fake response HttpResponse response = new HttpResponse(); response.setHeader('Content-Type', 'application/json'); response.setBody('{"animal":{"id":2,"name":"bear","eats":"berries, campers, adam seligman","says":"yum yum"}}'); response.setStatusCode(200); return response; }}