Salesforce Trailhead > APEX Integration Services > Apex REST Callouts

AnimalLocator.cls

public class AnimalLocator {
    public static string getAnimalNameById(Integer id){
        Http http = new Http();
        HttpRequest request = new HttpRequest();
        request.setEndpoint('https://th-apex-http-callout.herokuapp.com/animals/' + id);
        request.setMethod('GET');
        HttpResponse response = http.send(request);        
        string animalName = null;
        // If the request is successful, parse the JSON response.         
        if (response.getStatusCode() == 200) {
            // Deserialize into an animal
            JSON2Apex j = (JSON2Apex) JSON2Apex.parse(response.getBody());
            animalName = j.Animal.name;
        }
        return animalName;
    }
}

AnimalLocatorMock.cls

@isTest
global class AnimalLocatorMock implements HttpCalloutMock {
    // Implement this interface method
    global HTTPResponse respond(HTTPRequest request) {
        // Create a fake response
        HttpResponse response = new HttpResponse();
        response.setBody('{"animal":{"id":1,"name":"chicken","eats":"chicken food","says":"cluck cluck"}}');
        response.setStatusCode(200);
        return response; 
    }
}

AnimalLocatorTest.cls

@isTest
public class AnimalLocatorTest {
    @isTest 
    public static void testGetAnimalNameById() {
        AnimalLocatorMock mock = new AnimalLocatorMock();
        // Associate the callout with a mock response
        Test.setMock(HttpCalloutMock.class, mock);
        // Call method to test
        String animalName = AnimalLocator.getAnimalNameById(1);
        // Verify we got a chicken
        System.assertEquals('chicken', animalName,
        'The name of the test animal should be a chicken.');          
    }   
}

JSON2Apex.cls

public class JSON2Apex {
	public Animal animal;

	public class Animal {
		public Integer id;
		public String name;
		public String eats;
		public String says;
	}

	public static JSON2Apex parse(String json) {
		return (JSON2Apex) System.JSON.deserialize(json, JSON2Apex.class);
	}
}