The document discusses behavior-driven development (BDD) for testing RESTful iOS applications using the Kiwi and Nocilla frameworks. It describes BDD and how it differs from test-driven development (TDD) by focusing on specifying behavior rather than implementation. It then demonstrates using Kiwi to write BDD-style tests for an iOS view controller that retrieves GitHub repositories from the GitHub API. The tests are asynchronous to handle the network request, initially failing until the API client is implemented to make the actual network request.

1. iOS Behavior-Driven
Development
Testing RESTful Applications with Kiwi and Nocilla
March 9th, 2014
Brian Gesiak
Research Student, The University of Tokyo
@modocache #startup_ios

2. Today
• Behavior-driven development (BDD)
• iOS behavior-driven development
• Kiwi
• Testing asynchronous networking
• Nocilla

3. Test-Driving Network Code
Motivation
• Let’s say we want to display a user’s
repositories on GitHub
• We can GET JSON from the GitHub
API
• https://api.github.com/users/
{{ username }}/repos.json

4. Test-Driving Network Code
Motivation
/// GET /users/:username/repos
!
[
{
"id": 1296269,
"name": "Hello-World",
"description": "My first repo!",
/* ... */
}
]

5. Test-Driving Network Code
Demonstration

6. Building the App
Behavior-Driven Development Using Kiwi
• Behavior-driven development (BDD) is an extension of
test-driven development

7. Test-Driven Development

8. Test-Driven Development
• Red: Write a test and watch it fail

9. Test-Driven Development
• Red: Write a test and watch it fail
• Green: Pass the test (by writing as little code as possible)

10. Test-Driven Development
• Red: Write a test and watch it fail
• Green: Pass the test (by writing as little code as possible)
• Refactor: Remove duplication

11. Test-Driven Development
• Red: Write a test and watch it fail
• Green: Pass the test (by writing as little code as possible)
• Refactor: Remove duplication
• Repeat

12. Example of iOS TDD Using XCTest

13. Example of iOS TDD Using XCTest
// Create an XCTestCase subclass
@interface GHVRepoCollectionTests : XCTestCase
// The subject of our tests
@property (nonatomic, strong) GHVCollection *collection;
@end
!
@implementation GHVRepoCollectionTests
// Set up the `repos` collection for each test
- (void)setUp {
[super setUp];
self.collection = [GHVCollection new];
}
// Add a test
- (void)testAddingARepo {
// Add a repo
[self.collection addRepo:[GHVRepo new]];
!
// Assert the number of repos is now one
XCTAssertEqual([self.collection.repos count], 1,
@"Expected one repository");
}
@end

14. Example of iOS TDD Using XCTest
// Create an XCTestCase subclass
@interface GHVRepoCollectionTests : XCTestCase
// The subject of our tests
@property (nonatomic, strong) GHVCollection *collection;
@end
!
@implementation GHVRepoCollectionTests
// Set up the `repos` collection for each test
- (void)setUp {
[super setUp];
self.collection = [GHVCollection new];
}
// Add a test
- (void)testAddingARepo {
// Add a repo
[self.collection addRepo:[GHVRepo new]];
!
// Assert the number of repos is now one
XCTAssertEqual([self.collection.repos count], 1,
@"Expected one repository");
}
@end

15. Example of iOS TDD Using XCTest
// Create an XCTestCase subclass
@interface GHVRepoCollectionTests : XCTestCase
// The subject of our tests
@property (nonatomic, strong) GHVCollection *collection;
@end
!
@implementation GHVRepoCollectionTests
// Set up the `repos` collection for each test
- (void)setUp {
[super setUp];
self.collection = [GHVCollection new];
}
// Add a test
- (void)testAddingARepo {
// Add a repo
[self.collection addRepo:[GHVRepo new]];
!
// Assert the number of repos is now one
XCTAssertEqual([self.collection.repos count], 1,
@"Expected one repository");
}
@end

16. Example of iOS TDD Using XCTest
// Create an XCTestCase subclass
@interface GHVRepoCollectionTests : XCTestCase
// The subject of our tests
@property (nonatomic, strong) GHVCollection *collection;
@end
!
@implementation GHVRepoCollectionTests
// Set up the `repos` collection for each test
- (void)setUp {
[super setUp];
self.collection = [GHVCollection new];
}
// Add a test
- (void)testAddingARepo {
// Add a repo
[self.collection addRepo:[GHVRepo new]];
!
// Assert the number of repos is now one
XCTAssertEqual([self.collection.repos count], 1,
@"Expected one repository");
}
@end

17. Example of iOS TDD Using XCTest
// Create an XCTestCase subclass
@interface GHVRepoCollectionTests : XCTestCase
// The subject of our tests
@property (nonatomic, strong) GHVCollection *collection;
@end
!
@implementation GHVRepoCollectionTests
// Set up the `repos` collection for each test
- (void)setUp {
[super setUp];
self.collection = [GHVCollection new];
}
// Add a test
- (void)testAddingARepo {
// Add a repo
[self.collection addRepo:[GHVRepo new]];
!
// Assert the number of repos is now one
XCTAssertEqual([self.collection.repos count], 1,
@"Expected one repository");
}
@end

18. Example of iOS TDD Using XCTest
// Create an XCTestCase subclass
@interface GHVRepoCollectionTests : XCTestCase
// The subject of our tests
@property (nonatomic, strong) GHVCollection *collection;
@end
!
@implementation GHVRepoCollectionTests
// Set up the `repos` collection for each test
- (void)setUp {
[super setUp];
self.collection = [GHVCollection new];
}
// Add a test
- (void)testAddingARepo {
// Add a repo
[self.collection addRepo:[GHVRepo new]];
!
// Assert the number of repos is now one
XCTAssertEqual([self.collection.repos count], 1,
@"Expected one repository");
}
@end

19. Behavior-Driven Development
• Answers the question: “What do I test?”
• Behavioral tests don’t test the implementation, they
specify the behavior

20. iOS BDD Using Kiwi

21. iOS BDD Using Kiwi
// Describe how the `GHVCollection` class behaves
describe(@"GHVCollection", ^{
// Setup up the collection for each test
__block GHVCollection *collection = nil;
beforeEach(^{
collection = [GHVCollection new];
});
!
// Describe how the `-addRepo:` method behaves
describe(@"-addRepo:", ^{
context(@"after adding a repo", ^{
// Add a repo before each test
beforeEach(^{
[collection addRepo:[GHVRepo new]];
});
// Test the method behaves correctly
it(@"has a repo count of one", ^{
[[collection.repos should] haveCountOf:1];
});
});
});
});

22. iOS BDD Using Kiwi
// Describe how the `GHVCollection` class behaves
describe(@"GHVCollection", ^{
// Setup up the collection for each test
__block GHVCollection *collection = nil;
beforeEach(^{
collection = [GHVCollection new];
});
!
// Describe how the `-addRepo:` method behaves
describe(@"-addRepo:", ^{
context(@"after adding a repo", ^{
// Add a repo before each test
beforeEach(^{
[collection addRepo:[GHVRepo new]];
});
// Test the method behaves correctly
it(@"has a repo count of one", ^{
[[collection.repos should] haveCountOf:1];
});
});
});
});

23. iOS BDD Using Kiwi
// Describe how the `GHVCollection` class behaves
describe(@"GHVCollection", ^{
// Setup up the collection for each test
__block GHVCollection *collection = nil;
beforeEach(^{
collection = [GHVCollection new];
});
!
// Describe how the `-addRepo:` method behaves
describe(@"-addRepo:", ^{
context(@"after adding a repo", ^{
// Add a repo before each test
beforeEach(^{
[collection addRepo:[GHVRepo new]];
});
// Test the method behaves correctly
it(@"has a repo count of one", ^{
[[collection.repos should] haveCountOf:1];
});
});
});
});

24. iOS BDD Using Kiwi
// Describe how the `GHVCollection` class behaves
describe(@"GHVCollection", ^{
// Setup up the collection for each test
__block GHVCollection *collection = nil;
beforeEach(^{
collection = [GHVCollection new];
});
!
// Describe how the `-addRepo:` method behaves
describe(@"-addRepo:", ^{
context(@"after adding a repo", ^{
// Add a repo before each test
beforeEach(^{
[collection addRepo:[GHVRepo new]];
});
// Test the method behaves correctly
it(@"has a repo count of one", ^{
[[collection.repos should] haveCountOf:1];
});
});
});
});

25. iOS BDD Using Kiwi
// Describe how the `GHVCollection` class behaves
describe(@"GHVCollection", ^{
// Setup up the collection for each test
__block GHVCollection *collection = nil;
beforeEach(^{
collection = [GHVCollection new];
});
!
// Describe how the `-addRepo:` method behaves
describe(@"-addRepo:", ^{
context(@"after adding a repo", ^{
// Add a repo before each test
beforeEach(^{
[collection addRepo:[GHVRepo new]];
});
// Test the method behaves correctly
it(@"has a repo count of one", ^{
[[collection.repos should] haveCountOf:1];
});
});
});
});

26. iOS BDD Using Kiwi
// Describe how the `GHVCollection` class behaves
describe(@"GHVCollection", ^{
// Setup up the collection for each test
__block GHVCollection *collection = nil;
beforeEach(^{
collection = [GHVCollection new];
});
!
// Describe how the `-addRepo:` method behaves
describe(@"-addRepo:", ^{
context(@"after adding a repo", ^{
// Add a repo before each test
beforeEach(^{
[collection addRepo:[GHVRepo new]];
});
// Test the method behaves correctly
it(@"has a repo count of one", ^{
[[collection.repos should] haveCountOf:1];
});
});
});
});

27. Kiwi Benefits

28. Kiwi Benefits
• An unlimited amount of setup and teardown

29. Kiwi Benefits
• An unlimited amount of setup and teardown
beforeEach(^{
beforeAll(^{
afterEach(^{
afterAll(^{
/*
/*
/*
/*
...
...
...
...
*/
*/
*/
*/
});
});
});
});

30. Kiwi Benefits
• An unlimited amount of setup and teardown
beforeEach(^{
beforeAll(^{
afterEach(^{
afterAll(^{
• Mocks and stubs included
/*
/*
/*
/*
...
...
...
...
*/
*/
*/
*/
});
});
});
});

31. Kiwi Benefits
• An unlimited amount of setup and teardown
beforeEach(^{
beforeAll(^{
afterEach(^{
afterAll(^{
/*
/*
/*
/*
...
...
...
...
*/
*/
*/
*/
});
});
});
});
• Mocks and stubs included
[collection stub:@selector(addRepo:)];

32. Kiwi Benefits
• An unlimited amount of setup and teardown
beforeEach(^{
beforeAll(^{
afterEach(^{
afterAll(^{
/*
/*
/*
/*
...
...
...
...
*/
*/
*/
*/
});
});
});
});
• Mocks and stubs included
[collection stub:@selector(addRepo:)];
• Asynchronous testing support

33. Kiwi Benefits
• An unlimited amount of setup and teardown
beforeEach(^{
beforeAll(^{
afterEach(^{
afterAll(^{
/*
/*
/*
/*
...
...
...
...
*/
*/
*/
*/
});
});
});
});
• Mocks and stubs included
[collection stub:@selector(addRepo:)];
• Asynchronous testing support
[[collection.repos shouldEventually] haveCountOf:2];

34. Kiwi Benefits
• An unlimited amount of setup and teardown
beforeEach(^{
beforeAll(^{
afterEach(^{
afterAll(^{
/*
/*
/*
/*
...
...
...
...
*/
*/
*/
*/
});
});
});
});
• Mocks and stubs included
[collection stub:@selector(addRepo:)];
• Asynchronous testing support
[[collection.repos shouldEventually] haveCountOf:2];
• More readable than XCTest

35. Our First Failing Test

36. Our First Failing Test
/// GHVAPIClientSpec.m
!
it(@"gets repositories", ^{
// The repos returned by the API
__block NSArray *allRepos = nil;
!
// Fetch the repos from the API
[client allRepositoriesForUsername:@"modocache"
success:^(NSArray *repos) {
// Set the repos
allRepos = repos;
} failure:nil];
!
// Assert that the repos have been set
[[expectFutureValue(allRepos) shouldEventually]
haveCountOf:10];
});

37. Our First Failing Test
/// GHVAPIClientSpec.m
!
it(@"gets repositories", ^{
// The repos returned by the API
__block NSArray *allRepos = nil;
!
// Fetch the repos from the API
[client allRepositoriesForUsername:@"modocache"
success:^(NSArray *repos) {
// Set the repos
allRepos = repos;
} failure:nil];
!
// Assert that the repos have been set
[[expectFutureValue(allRepos) shouldEventually]
haveCountOf:10];
});

38. Our First Failing Test
/// GHVAPIClientSpec.m
!
it(@"gets repositories", ^{
// The repos returned by the API
__block NSArray *allRepos = nil;
!
// Fetch the repos from the API
[client allRepositoriesForUsername:@"modocache"
success:^(NSArray *repos) {
// Set the repos
allRepos = repos;
} failure:nil];
!
// Assert that the repos have been set
[[expectFutureValue(allRepos) shouldEventually]
haveCountOf:10];
});

39. Our First Failing Test
/// GHVAPIClientSpec.m
!
it(@"gets repositories", ^{
// The repos returned by the API
__block NSArray *allRepos = nil;
!
// Fetch the repos from the API
[client allRepositoriesForUsername:@"modocache"
success:^(NSArray *repos) {
// Set the repos
allRepos = repos;
} failure:nil];
!
// Assert that the repos have been set
[[expectFutureValue(allRepos) shouldEventually]
haveCountOf:10];
});

40. Our First Failing Test
/// GHVAPIClientSpec.m
!
it(@"gets repositories", ^{
// The repos returned by the API
__block NSArray *allRepos = nil;
!
// Fetch the repos from the API
[client allRepositoriesForUsername:@"modocache"
success:^(NSArray *repos) {
// Set the repos
allRepos = repos;
} failure:nil];
!
// Assert that the repos have been set
[[expectFutureValue(allRepos) shouldEventually]
haveCountOf:10];
});

41. Our First Failing Test
/// GHVAPIClientSpec.m
!
it(@"gets repositories", ^{
// The repos returned by the API
__block NSArray *allRepos = nil;
!
// Fetch the repos from the API
[client allRepositoriesForUsername:@"modocache"
success:^(NSArray *repos) {
// Set the repos
allRepos = repos;
} failure:nil];
!
// Assert that the repos have been set
[[expectFutureValue(allRepos) shouldEventually]
haveCountOf:10];
});

42. Going Green

43. Going Green
/// GHVAPIClient.m
!
// Create a request operation manager pointing at the GitHub API
NSString *urlString = @"https://api.github.com/";
NSURL *baseURL = [NSURL URLWithString:urlString];
AFHTTPRequestOperationManager *manager =
[[AFHTTPRequestOperationManager alloc] initWithBaseURL:baseURL];
!
// The manager should serialize the response as JSON
manager.requestSerializer = [AFJSONRequestSerializer serializer];
!
// Send a request to GET /users/:username/repos
[manager GET:[NSString stringWithFormat:@"users/%@/repos",
username]
parameters:nil
success:^(AFHTTPRequestOperation *operation,
id responseObject) {
// Send response object to success block
success(responseObject);
}
failure:nil];
}

44. Going Green
/// GHVAPIClient.m
!
// Create a request operation manager pointing at the GitHub API
NSString *urlString = @"https://api.github.com/";
NSURL *baseURL = [NSURL URLWithString:urlString];
AFHTTPRequestOperationManager *manager =
[[AFHTTPRequestOperationManager alloc] initWithBaseURL:baseURL];
!
// The manager should serialize the response as JSON
manager.requestSerializer = [AFJSONRequestSerializer serializer];
!
// Send a request to GET /users/:username/repos
[manager GET:[NSString stringWithFormat:@"users/%@/repos",
username]
parameters:nil
success:^(AFHTTPRequestOperation *operation,
id responseObject) {
// Send response object to success block
success(responseObject);
}
failure:nil];
}

45. Going Green
/// GHVAPIClient.m
!
// Create a request operation manager pointing at the GitHub API
NSString *urlString = @"https://api.github.com/";
NSURL *baseURL = [NSURL URLWithString:urlString];
AFHTTPRequestOperationManager *manager =
[[AFHTTPRequestOperationManager alloc] initWithBaseURL:baseURL];
!
// The manager should serialize the response as JSON
manager.requestSerializer = [AFJSONRequestSerializer serializer];
!
// Send a request to GET /users/:username/repos
[manager GET:[NSString stringWithFormat:@"users/%@/repos",
username]
parameters:nil
success:^(AFHTTPRequestOperation *operation,
id responseObject) {
// Send response object to success block
success(responseObject);
}
failure:nil];
}

46. Going Green
/// GHVAPIClient.m
!
// Create a request operation manager pointing at the GitHub API
NSString *urlString = @"https://api.github.com/";
NSURL *baseURL = [NSURL URLWithString:urlString];
AFHTTPRequestOperationManager *manager =
[[AFHTTPRequestOperationManager alloc] initWithBaseURL:baseURL];
!
// The manager should serialize the response as JSON
manager.requestSerializer = [AFJSONRequestSerializer serializer];
!
// Send a request to GET /users/:username/repos
[manager GET:[NSString stringWithFormat:@"users/%@/repos",
username]
parameters:nil
success:^(AFHTTPRequestOperation *operation,
id responseObject) {
// Send response object to success block
success(responseObject);
}
failure:nil];
}

47. Going Green
/// GHVAPIClient.m
!
// Create a request operation manager pointing at the GitHub API
NSString *urlString = @"https://api.github.com/";
NSURL *baseURL = [NSURL URLWithString:urlString];
AFHTTPRequestOperationManager *manager =
[[AFHTTPRequestOperationManager alloc] initWithBaseURL:baseURL];
!
// The manager should serialize the response as JSON
manager.requestSerializer = [AFJSONRequestSerializer serializer];
!
// Send a request to GET /users/:username/repos
[manager GET:[NSString stringWithFormat:@"users/%@/repos",
username]
parameters:nil
success:^(AFHTTPRequestOperation *operation,
id responseObject) {
// Send response object to success block
success(responseObject);
}
failure:nil];
}

48. Problems with our Test
• The test has external dependencies
• It’ll fail if the GitHub API is down
• It’ll fail if run without an internet connection
• It’ll fail if the response is too slow
• The test is slow
• It sends a request every time it’s run

49. HTTP Stubbing
Eliminating external dependencies
stubRequest(@"GET",
@“https://api.github.com/"
@“users/modocache/repos")
.andReturn(200)
.withHeaders(@{@"Content-Type": @"application/json"})
.withBody(@"["repo-1"]");
!
GHVAPIClient *client = [GHVAPIClient new];
!
// ...
!
[[expectFutureValue(allRepos) shouldEventually]
haveCountOf:1];

50. HTTP Stubbing
Eliminating external dependencies
stubRequest(@"GET",
@“https://api.github.com/"
@“users/modocache/repos")
.andReturn(200)
.withHeaders(@{@"Content-Type": @"application/json"})
.withBody(@"["repo-1"]");
!
GHVAPIClient *client = [GHVAPIClient new];
!
// ...
!
[[expectFutureValue(allRepos) shouldEventually]
haveCountOf:1];

51. HTTP Stubbing
Eliminating external dependencies
stubRequest(@"GET",
@“https://api.github.com/"
@“users/modocache/repos")
.andReturn(200)
.withHeaders(@{@"Content-Type": @"application/json"})
.withBody(@"["repo-1"]");
!
GHVAPIClient *client = [GHVAPIClient new];
!
// ...
!
[[expectFutureValue(allRepos) shouldEventually]
haveCountOf:1];

52. HTTP Stubbing
Eliminating external dependencies
stubRequest(@"GET",
@“https://api.github.com/"
@“users/modocache/repos")
.andReturn(200)
.withHeaders(@{@"Content-Type": @"application/json"})
.withBody(@"["repo-1"]");
!
GHVAPIClient *client = [GHVAPIClient new];
!
// ...
!
[[expectFutureValue(allRepos) shouldEventually]
haveCountOf:1];

53. HTTP Stubbing
Eliminating external dependencies
stubRequest(@"GET",
@“https://api.github.com/"
@“users/modocache/repos")
.andReturn(200)
.withHeaders(@{@"Content-Type": @"application/json"})
.withBody(@"["repo-1"]");
!
GHVAPIClient *client = [GHVAPIClient new];
!
// ...
!
[[expectFutureValue(allRepos) shouldEventually]
haveCountOf:1];

54. HTTP Stubbing
Eliminating external dependencies
stubRequest(@"GET",
@“https://api.github.com/"
@“users/modocache/repos")
.andReturn(200)
.withHeaders(@{@"Content-Type": @"application/json"})
.withBody(@"["repo-1"]");
!
GHVAPIClient *client = [GHVAPIClient new];
!
// ...
!
[[expectFutureValue(allRepos) shouldEventually]
haveCountOf:1];

55. Problems Nocilla Fixes
• The test no longer has external dependencies
• It’ll pass whether the GitHub API is online or not
• It’ll pass even when run offline
• The test is fast
• It still sends a request, but that request is immediately
intercepted and a response is returned

56. Other Nocilla Features

57. Other Nocilla Features
• Stub HTTP requests using regular expressions

58. Other Nocilla Features
• Stub HTTP requests using regular expressions
stubRequest(@"GET",
@"https://api.github.com/"
@"users/(.*?)/repos".regex)

59. Other Nocilla Features
• Stub HTTP requests using regular expressions
stubRequest(@"GET",
@"https://api.github.com/"
@"users/(.*?)/repos".regex)
• Return errors, such as for poor internet connection

60. Other Nocilla Features
• Stub HTTP requests using regular expressions
stubRequest(@"GET",
@"https://api.github.com/"
@"users/(.*?)/repos".regex)
• Return errors, such as for poor internet connection
NSError *error =
[NSError errorWithDomain:NSURLErrorDomain
code:29
userInfo:@{NSLocalizedDescriptionKey: @"Uh-oh!"}];
stubRequest(@"GET", @"...")
.andFailWithError(error);

61. Takeaways

62. Takeaways
• Readable, behavior-driven, asynchronous tests with Kiwi
• https://github.com/allending/Kiwi

63. Takeaways
• Readable, behavior-driven, asynchronous tests with Kiwi
• https://github.com/allending/Kiwi
pod "Kiwi/XCTest"

64. Takeaways
• Readable, behavior-driven, asynchronous tests with Kiwi
• https://github.com/allending/Kiwi
pod "Kiwi/XCTest"
• Eliminate network dependencies with Nocilla
• https://github.com/luisobo/Nocilla

65. Takeaways
• Readable, behavior-driven, asynchronous tests with Kiwi
• https://github.com/allending/Kiwi
pod "Kiwi/XCTest"
• Eliminate network dependencies with Nocilla
• https://github.com/luisobo/Nocilla
pod "Nocilla"

66. Questions?
@modocache #startup_ios

67. Questions?
@modocache #startup_ios
describe(@"this talk", ^{
context(@"after presenting the slides", ^{
it(@"moves to Q&A", ^{
[[you should] askQuestions];
[[you shouldEventually]
receive:@selector(stop)];
});
});
});

68. Questions?
@modocache #startup_ios
describe(@"this talk", ^{
context(@"after presenting the slides", ^{
it(@"moves to Q&A", ^{
[[you should] askQuestions];
[[you shouldEventually]
receive:@selector(stop)];
});
});
});

69. Questions?
@modocache #startup_ios
describe(@"this talk", ^{
context(@"after presenting the slides", ^{
it(@"moves to Q&A", ^{
[[you should] askQuestions];
[[you shouldEventually]
receive:@selector(stop)];
});
});
});

70. Questions?
@modocache #startup_ios
describe(@"this talk", ^{
context(@"after presenting the slides", ^{
it(@"moves to Q&A", ^{
[[you should] askQuestions];
[[you shouldEventually]
receive:@selector(stop)];
});
});
});

71. Questions?
@modocache #startup_ios
describe(@"this talk", ^{
context(@"after presenting the slides", ^{
it(@"moves to Q&A", ^{
[[you should] askQuestions];
[[you shouldEventually]
receive:@selector(stop)];
});
});
});