Behavioral-driven development of a sample app using Kiwi and Nocilla.

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)];
});
});
});