Objective-C iOS API Mocking using XCTest (Xcode 8.1) & OHHTTPStub v5.2.3

loginData.json

{
    "address": "4/16-D, Civil Lines, Airport Road",
    "city": "Jaipur",
    "created_at": "2016-03-15T09:58:26Z",
    "email": "test_email@email.com",
    "email_verified": false,
    "first_name": "Test",
    "gender": "male",
    "id": 123456,
    "last_name": "User",
    "state": "Rajasthan",
    "updated_at": "2016-03-15T09:58:26Z",
    "zip_code": "302001",
    "authentication_token": "test_auth_token",
    "referral_code": "test_referral_code",
}

MockAPITest.m

//
//  MockAPITest.m
//  iOS-API-Mock-Test
//
//  Created by gauravds on 28/12/16.
//  Copyright © 2016 iOS Dev Group. All rights reserved.
//

#import "ModelTestHelper.h"

#define kLoginData @"LoginData"
#define kLoginDataStaging @"LoginDataStaging"

@interface MockAPITest : ModelTestHelper

@end

@implementation MockAPITest

- (void)testLogin {
    XCTestExpectation *expectation = [self stubFileName:@"loginData.json"];
  
  //-- Here API is called and response will come through Stub.
    [[UserManager sharedInstance] loginWithEmail:@"test_email@email.com"
                                        password:@"password123"
                                        response:^(BOOL result, id result) {
                                                [expectation fulfill];
                                        }];
    
    [self waitForExpectationsWithTimeout:self.timeout
                                 handler:^(NSError *error) {
        if (error) {
            NSLog(@"XCTest Request Timeout Error: %@", error);
        }
    }];
}

- (void)testReadFile {
  // -- prints string content of file in test project
    NSLog(@"loginData read from file : %@", [self readFile:@"loginData.json"]);
}

@end

ModelTestHelper.h

//
//  ModelTestHelper.h
//  iOS-API-Mock-Test
//
//  Created by gauravds on 28/12/16.
//  Copyright © 2016 iOS Dev Group. All rights reserved.
//

#import <XCTest/XCTest.h>

@interface ModelTestHelper : XCTestCase

- (double)timeout;
- (NSString*)readFile:(NSString*)filename;

- (XCTestExpectation*)stubFileName:(NSString*)fileName;
- (XCTestExpectation*)stubCode:(int)statusCode fileName:(NSString*)fileName;
- (XCTestExpectation*)stubCode:(int)statusCode fileName:(NSString*)fileName header:(NSDictionary*)headers;

@end

ModelTestHelper.m

//
//  ModelTestHelper.m
//  iOS-API-Mock-Test
//
//  Created by gauravds on 28/12/16.
//  Copyright © 2016 iOS Dev Group. All rights reserved.
//

#import "ModelTestHelper.h"
#import <OHHTTPStubs/OHHTTPStubs.h>
#import <OHHTTPStubs/OHPathHelpers.h>

@implementation ModelTestHelper

- (void)tearDown {
    [OHHTTPStubs removeAllStubs];
    [super tearDown];
}

#pragma mark - Common
- (double)timeout {
    return 10.0;
}

- (NSString*)readFile:(NSString*)filename {
    NSBundle *bundle = [NSBundle bundleForClass:self.class];
    NSString *path = [bundle pathForResource:filename ofType:nil];
    return [NSString stringWithContentsOfFile:path
                                     encoding:NSUTF8StringEncoding
                                        error:NULL];
}

#pragma mark - OHHTTPStub
- (XCTestExpectation*)stubFileName:(NSString*)fileName {
    return [self stubCode:200 fileName:fileName header:nil];
}

- (XCTestExpectation*)stubCode:(int)statusCode fileName:(NSString*)fileName {
   return [self stubCode:statusCode fileName:fileName header:nil];
}

- (XCTestExpectation*)stubCode:(int)statusCode fileName:(NSString*)fileName header:(NSDictionary*)headers {
    NSMutableDictionary *headersMut = [@{@"Content-Type": @"application/json"} mutableCopy];
    if (headers) {
        [headersMut addEntriesFromDictionary:headers];
    }
    [OHHTTPStubs stubRequestsPassingTest:^BOOL(NSURLRequest * _Nonnull request) {
        return YES;
    }
                        withStubResponse:^OHHTTPStubsResponse * _Nonnull(NSURLRequest * _Nonnull request) {
                            return [[OHHTTPStubsResponse alloc] initWithFileAtPath:OHPathForFile(fileName, self.class)
                                                                        statusCode:statusCode
                                                                           headers:headersMut];
                        }];
    return [self expectationWithDescription:@"API response expectation"];
}

@end