apex-http-mock

HttpMock.cls

@IsTest
public class HttpMock implements HttpCalloutMock {

    private static final String ANY_URL = null;

    private Map<String, Map<String, Object>> responses = new Map<String, Map<String, Object>>();


    // PUBLIC

    public HttpMock get(String url, Object body, Integer statusCode) {
        return mock('GET', url, body, statusCode);
    }


    public HttpMock get(String url, Object body) {
        return get(url, body, 200);
    }


    public HttpMock get(Object body, Integer statusCode) {
        return get(ANY_URL, body, 200);
    }


    public HttpMock post(String url, Object body, Integer statusCode) {
        return mock('POST', url, body, statusCode);
    }


    public HttpMock post(String url, Object body) {
        return post(url, body, 200);
    }


    public HttpMock post(Object body, Integer statusCode) {
        return post(ANY_URL, body, 200);
    }


    public HttpMock put(String url, Object body, Integer statusCode) {
        return mock('PUT', url, body, statusCode);
    }


    public HttpMock put(String url, Object body) {
        return put(url, body, 200);
    }


    public HttpMock put(Object body, Integer statusCode) {
        return put(ANY_URL, body, 200);
    }


    public void mock() {
        Test.setMock(HttpCalloutMock.class, this);
    }


    // implements HttpCalloutMock

    public HttpResponse respond(HttpRequest request) {
        HttpResponse result = badRequest();

        String method = request.getMethod();

        if(responses.containsKey(method)) {
            for(String url : responses.get(method).keySet()) {
                if(url == ANY_URL || request.getEndpoint().containsIgnoreCase(url)) {
                    Object response = responses.get(method).get(url);

                    if(response instanceof Exception) {
                        throw (Exception) response;
                    }
                    else {
                        result = (HttpResponse) response;
                    }

                    break;
                }
            }
        }

        return result;
    }

    // PRIVATE

    private HttpMock mock(String method, String url, Object body, Integer statusCode) {
        if(!responses.containsKey(method)) {
            responses.put(method, new Map<String, Object>());
        }

        if(body instanceof Exception) {
            responses.get(method).put(url, body);
        }
        else {
            HttpResponse response = new HttpResponse();
            response.setHeader('Content-Type', 'application/json');
            response.setStatusCode(statusCode);
            response.setBody(JSON.serialize(body));

            responses.get(method).put(url, response);
        }

        return this;
    }


    private HttpMock mock(String method, String url, Object body) {
        return mock(method, url, body, 200);
    }


    private HttpMock mock(String method, Object body, Integer statusCode) {
        return mock(method, ANY_URL, body, 200);
    }


    private HttpResponse badRequest() {
        HttpResponse result = new HttpResponse();
        result.setStatusCode(500);
        result.setStatus('Invalid Request');
        result.setBody('{}');
        return result;
    }
}

HttpMock_Test.cls

@IsTest
private class HttpMock_Test {

    private static final PersonApi API = new PersonApi();
    private static final Person JOE = new Person('joe');
    private static final Person TIM = new Person('tim');


    @IsTest
    private static void multipleEndpointFragments() {

        // Setup
        new HttpMock()
                .get('/v2/persons', new List<Person>{ JOE, TIM },200)
                .get('/v2/person/tim', TIM, 200)
                .mock();


        // Exercise + Verify
        Test.startTest();

        System.assertEquals(2, API.getPersons().size());
        System.assertEquals('tim', API.getPerson('tim').name);

        Test.stopTest();
    }


    @IsTest
    private static void multipleHttpMethods() {

        // Setup
        new HttpMock()
            .get('/v2/person/tim', TIM, 200)
            .post('/v2/person/tim', true, 200)
            .mock();


        // Exercise + Verify
        Test.startTest();

        System.assertEquals(true,  API.updatePerson(new Person('tim')) );
        System.assertEquals('tim', API.getPerson('tim').name);

        Test.stopTest();
    }


    @IsTest
    private static void fail() {

        // Setup
        new HttpMock()
                .get('/v2/persons', new CalloutException())
                .mock();


        // Exercise + Verify
        try {
            Test.startTest();
            API.getPersons();
            Test.stopTest();

            System.assert(false);
        }
        catch(CalloutException ex) {
            System.assert(true);
        }
    }


    // HELPER

    private class PersonApi {
        public List<Person> getPersons() {
            HttpRequest request = new HttpRequest();
            request.setEndpoint('/v2/persons');
            request.setMethod('GET');
            return (List<Person>) JSON.deserialize(new Http().send(request).getBody(), List<Person>.class);
        }

        public Person getPerson(String name) {
            HttpRequest request = new HttpRequest();
            request.setMethod('GET');
            request.setEndpoint('/v2/person/'+name);
            return (Person) JSON.deserialize(new Http().send(request).getBody(), Person.class);
        }

        public Boolean updatePerson(Person person) {
            try {
                HttpRequest request = new HttpRequest();
                request.setMethod('POST');
                request.setEndpoint('/v2/person/'+person.name);
                new Http().send(request);
            }
            catch(Exception ex){
                return false;
            }

            return true;
        }
    }


    private class Person {
        public String name;

        public Person(String name) {
            this.name = name;
        }
    }
}