iOS Behavior-Driven Development

iOS Behavior-Driven DevelopmentTesting RESTful Applications with Kiwi and Nocilla

Brian Gesiak

March 9th, 2014

Research Student, The University of Tokyo

@modocache #startup_ios

Today

• Behavior-driven development (BDD) • iOS behavior-driven development

• Kiwi • Testing asynchronous networking

• Nocilla

Test-Driving Network Code

• 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

Motivation

Test-Driving Network CodeMotivation

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

Test-Driving Network CodeDemonstration

Building the AppBehavior-Driven Development Using Kiwi

• Behavior-driven development (BDD) is an extension of test-driven development

Test-Driven Development

Test-Driven Development

• Red: Write a test and watch it fail

Test-Driven Development

• Red: Write a test and watch it fail• Green: Pass the test (by writing as little code as possible)

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

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

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

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

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

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

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

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

Example of iOS TDD Using XCTest

Behavior-Driven Development

• Answers the question: “What do I test?” • Behavioral tests don’t test the implementation, they specify the behavior

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

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

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

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

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

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

iOS BDD Using Kiwi

Kiwi Benefits

Kiwi Benefits

• An unlimited amount of setup and teardown

Kiwi Benefits

• An unlimited amount of setup and teardownbeforeEach(^{ /* ... */ }); beforeAll(^{ /* ... */ }); afterEach(^{ /* ... */ }); afterAll(^{ /* ... */ });

Kiwi Benefits

• An unlimited amount of setup and teardownbeforeEach(^{ /* ... */ }); beforeAll(^{ /* ... */ }); afterEach(^{ /* ... */ }); afterAll(^{ /* ... */ });

• Mocks and stubs included

Kiwi Benefits

• An unlimited amount of setup and teardownbeforeEach(^{ /* ... */ }); beforeAll(^{ /* ... */ }); afterEach(^{ /* ... */ }); afterAll(^{ /* ... */ });

• Mocks and stubs included[collection stub:@selector(addRepo:)];

Kiwi Benefits

• An unlimited amount of setup and teardownbeforeEach(^{ /* ... */ }); beforeAll(^{ /* ... */ }); afterEach(^{ /* ... */ }); afterAll(^{ /* ... */ });

• Mocks and stubs included[collection stub:@selector(addRepo:)];

• Asynchronous testing support

Kiwi Benefits

• An unlimited amount of setup and teardownbeforeEach(^{ /* ... */ }); beforeAll(^{ /* ... */ }); afterEach(^{ /* ... */ }); afterAll(^{ /* ... */ });

• Mocks and stubs included[collection stub:@selector(addRepo:)];

• Asynchronous testing support[[collection.repos shouldEventually] haveCountOf:2];

Kiwi Benefits

• An unlimited amount of setup and teardownbeforeEach(^{ /* ... */ }); beforeAll(^{ /* ... */ }); afterEach(^{ /* ... */ }); afterAll(^{ /* ... */ });

• Mocks and stubs included[collection stub:@selector(addRepo:)];

• Asynchronous testing support[[collection.repos shouldEventually] haveCountOf:2];

• More readable than XCTest

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]; });

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]; });

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]; });

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]; });

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]; });

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]; });

Our First Failing Test

Going Green

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]; }

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]; }

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]; }

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]; }

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]; }

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

HTTP Stubbing

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];

Eliminating external dependencies

HTTP Stubbing

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];

Eliminating external dependencies

HTTP Stubbing

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];

Eliminating external dependencies

HTTP Stubbing

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];

Eliminating external dependencies

HTTP Stubbing

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];

Eliminating external dependencies

HTTP Stubbing

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];

Eliminating external dependencies

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

Other Nocilla Features

Other Nocilla Features

• Stub HTTP requests using regular expressions

Other Nocilla Features

• Stub HTTP requests using regular expressionsstubRequest(@"GET", @"https://api.github.com/" @"users/(.*?)/repos".regex)

Other Nocilla Features

• Stub HTTP requests using regular expressionsstubRequest(@"GET", @"https://api.github.com/" @"users/(.*?)/repos".regex)

• Return errors, such as for poor internet connection

Other Nocilla Features

• Stub HTTP requests using regular expressionsstubRequest(@"GET", @"https://api.github.com/" @"users/(.*?)/repos".regex)

• Return errors, such as for poor internet connectionNSError *error = [NSError errorWithDomain:NSURLErrorDomain code:29 userInfo:@{NSLocalizedDescriptionKey: @"Uh-oh!"}]; stubRequest(@"GET", @"...") .andFailWithError(error);

Takeaways

Takeaways

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

Takeaways

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

pod "Kiwi/XCTest"

Takeaways

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

• Eliminate network dependencies with Nocilla • https://github.com/luisobo/Nocilla

pod "Kiwi/XCTest"

Takeaways

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

• Eliminate network dependencies with Nocilla • https://github.com/luisobo/Nocilla

pod "Kiwi/XCTest"

pod "Nocilla"

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

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

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

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

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

Questions?@modocache #startup_ios