iOS Unit Testing Workshop

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Unit Testing for iOS $> git clone --recursive https://github.com/moredip/run2bart-iOS.git $> cd run2bart-iOS $> open Run2Bart/Run2Bart.xcworkspace you should have already done this:

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me me me Pete Hodgson Consultant at ThoughtWorks @ph1 blog.thepete.net

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tell me about yourself experience with iOS? experience with automated testing? experience testing with iOS?

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goals for the workshop hands on experience good testing practices overview of all the major moving parts of Kiwi introduction to the advanced stuff

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some theory, some hands-on (with pairing!) workshop format

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interrupt, raise your hand, ask questions Please

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why should you care? Unit Testing

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1. write code 2. submit stack of cards 3. wait (probably overnight) 4. find out if your program worked

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Feedback

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write it check it

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feedback

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24 hrs punchcards

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60 mins big ol’ C++ program

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http://xkcd.com/303/

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10 secs an iOS app

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what’s next?

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of feedback speed

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of feedback quality

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syntax vs. semantics

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does it compile? static analysis unit testing

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unit testing means better feedback

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what is a unit test?

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what is NOT unit test?

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types of automated testing

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Your App End User Backend Services

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Unit Test Your App End User Backend Services

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Integration Test Your App End User Backend Services

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Acceptance Test Your App End User Backend Services

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Acceptance Test Your App End User Backend Services The App

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Acceptance Unit Integration

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“my first unit test” with kiwi

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what is kiwi? open-source tool builds on top of stock XCode tooling adds nicer ways of organizing tests adds nicer ways to make assertions adds ability to mock/stub

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setting up a project to use Kiwi

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Guide: Up and Running with Kiwi https://github.com/allending/Kiwi/wiki

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CocoaPods makes this a lot easier https://github.com/CocoaPods/CocoaPods

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what is a unit test?

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x+1 12 13

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system under test in out

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#import "Kiwi.h" SPEC_BEGIN(MyFirstSpec) describe(@"Basic Arithmetic", ^{ it(@"can increment 12",^{ [[theValue(12+1) should] equal:theValue(13)]; }); }); SPEC_END myFirstSpec.m

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Hands-on: writing our first test

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$> git checkout sl-2 $> git clean -dxf 1: Close XCode 2: 3: Open Run2Bart.xcworkspace

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#import "Kiwi.h" SPEC_BEGIN(MyFirstSpec) describe(@"Basic Arithmetic", ^{ it(@"can increment 12",^{ [[theValue(12+1) should] equal:theValue(13)]; }); }); SPEC_END ExampleSpec.m

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12+1 does equal 13 does 12*2 equal 24?

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#import "Kiwi.h" SPEC_BEGIN(MyFirstSpec) describe(@"Basic Arithmetic", ^{ it(@"can increment 12",^{ [[theValue(12+1) should] equal:theValue(13)]; }); }); SPEC_END ExampleSpec.m

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testing ‘real’ app code parsing JSON

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Introducing: Run2Bart

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parsing JSON

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@implementation Station + (NSArray *)loadStations:(NSArray *)rawStations { NSMutableArray *stations = [NSMutableArray array]; for(NSDictionary *rawStation in rawStations){ Station *station = [[Station alloc] initWithName:rawStation[@"name"] abbr:rawStation[@"abbr"]]; [stations addObject:station]; } return stations; } - (id)initWithName:(NSString *)name abbr:(NSString *)abbr { self = [super init]; if (self) { _name = [name copy]; ! ! _abbr = [abbr copy]; } return self; } @end Station.m

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system under test in out

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[ { “name”:”foo”, ... }, {...} ] Station loadStations

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describe(@"Station", ^{ it(@"loads from JSON correctly",^{ NSArray *rawStations = @[ @{@"abbr":@"s1",@"name":@"station one"}, @{@"abbr":@"s2",@"name":@"station two"}, ]; NSArray *stations = [Station loadStations:rawStations]; [[theValue(stations.count) should] equal:theValue(2)]; [[[stations[0] abbr] should] equal:@"s1"]; [[[stations[0] name] should] equal:@"station one"]; [[[stations[1] abbr] should] equal:@"s2"]; [[[stations[1] name] should] equal:@"station two"]; }); }); StationSpec.m

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Arrange, Act, Assert

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describe(@"Station", ^{ it(@"loads from JSON correctly",^{ ////////////////// // Arrange NSArray *rawStations = @[ @{@"abbr":@"s1",@"name":@"station one"}, @{@"abbr":@"s2",@"name":@"station two"}, ]; ////////////////// // Act NSArray *stations = [Station loadStations:rawStations]; ////////////////// // Assert [[theValue(stations.count) should] equal:theValue(2)]; [[[stations[0] abbr] should] equal:@"s1"]; [[[stations[0] name] should] equal:@"station one"]; [[[stations[1] abbr] should] equal:@"s2"]; [[[stations[1] name] should] equal:@"station two"]; }); });

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Given, When, Then

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describe(@"Station", ^{ it(@"loads from JSON correctly",^{ ////////////////// // Given NSArray *rawStations = @[ @{@"abbr":@"s1",@"name":@"station one"}, @{@"abbr":@"s2",@"name":@"station two"}, ]; ////////////////// // When NSArray *stations = [Station loadStations:rawStations]; ////////////////// // Then [[theValue(stations.count) should] equal:theValue(2)]; [[[stations[0] abbr] should] equal:@"s1"]; [[[stations[0] name] should] equal:@"station one"]; [[[stations[1] abbr] should] equal:@"s2"]; [[[stations[1] name] should] equal:@"station two"]; }); });

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another simple test displaying estimated departures

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5 “5 mins” etdToDisplay

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#import "Kiwi.h" #import "UpcomingDeparture.h" SPEC_BEGIN(UpcomingDepartureSpec) describe(@"[UpcomingDeparture etdToDisplay]", ^{ it(@"is correct for an etd of 5",^{ UpcomingDeparture *upcomingDeparture = [[UpcomingDeparture alloc] initWithDestinationName:@"blah" etd:@(5)]; [[[upcomingDeparture etdToDisplay] should] equal:@"5 mins"]; }); }); SPEC_END UpcomingDepartureSpec.m

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- (NSString *) etdToDisplay{ return [NSString stringWithFormat:@"%@ mins", self.etdInMinutes]; } UpcomingDeparture.m

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5 “5 mins” etdToDisplay

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etdToDisplay 1 “1 min” 5 “5 mins”

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etdToDisplay 0 “now” 5 “5 mins” 1 “1 min”

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Let’s do some TDD!

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describe(@"[UpcomingDeparture etdToDisplay]", ^{ it(@"is correct for an etd of 5",^{ UpcomingDeparture *upcomingDeparture = [[UpcomingDeparture alloc] initWithDestinationName:@"blah" etd:@(5)]; [[[upcomingDeparture etdToDisplay] should] equal:@"5 mins"]; }); it(@"is correct for an etd of 1",^{ UpcomingDeparture *upcomingDeparture = [[UpcomingDeparture alloc] initWithDestinationName:@"blah" etd:@(1)]; [[[upcomingDeparture etdToDisplay] should] equal:@"1 min"]; }); it(@"is correct for an etd of 0",^{ UpcomingDeparture *upcomingDeparture = [[UpcomingDeparture alloc] initWithDestinationName:@"blah" etd:@(0)]; [[[upcomingDeparture etdToDisplay] should] equal:@"now"]; }); }); UpcomingDepartureSpec.m

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edge-cases made easier

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~ BREAK? ~

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testing UIKit code

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$> git checkout sl-3 $> git clean -dxf 1: Close XCode 2: 3: Open Run2Bart.xcworkspace

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- (id)initForStation:(Station *)station { self = [super init]; if (self) { self.station = station; self.title = station.name; self.bartClient = [AppDelegate sharedInstance].bartClient; } return self; } UpcomingDeparturesViewController.m

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SPEC_BEGIN(UpcomingDeparturesViewControllerSpec) describe( @"UpcomingDeparturesViewController ", ^{ it( @"has the station's name as the title", ^{ // Given Station *theStation = [[Station alloc] initWithName:@"station name" abbr:@"station-abbr"]; UpcomingDeparturesViewController *theDeparturesVC = [[UpcomingDeparturesViewController alloc] initForStation:theStation]; // Then [[theDeparturesVC.title should] equal:@"station name"]; }); // ... UpcomingDeparturesViewControllerSpec.m

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UIKit code is still just code

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testing UIKit code rendering UITableViewCells

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- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CellIdentifier = @"Cell"; UpcomingDeparture *departure = [self.departures objectAtIndex:indexPath.row]; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if( !cell ) cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:CellIdentifier]; cell.textLabel.font = [UIFont systemFontOfSize:18.0]; cell.detailTextLabel.font = [UIFont systemFontOfSize:24.0]; cell.textLabel.text = departure.destinationName; cell.detailTextLabel.text = departure.etdToDisplay; return cell; } UpcomingDeparturesViewController.m

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describe(@"rendering departures", ^{ it( @"renders a table view cell for each departure", ^{ // Given UITableView *ignoredTableView = nil; Station *someStation = [[Station alloc] initWithName:@"station name" abbr:@"station-abbr"]; UpcomingDeparturesViewController *departuresVC = [[UpcomingDeparturesViewController alloc] initForStation:someStation]; NSArray *departures = @[ [[UpcomingDeparture alloc] initWithDestinationName:@"dest 1" etd:@(0)], [[UpcomingDeparture alloc] initWithDestinationName:@"dest 2" etd:@(1)], [[UpcomingDeparture alloc] initWithDestinationName:@"dest 3" etd:@(2)] ]; departuresVC.departures = departures; // When NSInteger numSections = [departuresVC numberOfSectionsInTableView:ignoredTableView]; NSInteger numRows = [departuresVC tableView:ignoredTableView numberOfRowsInSection:0]; // Then [[theValue(numSections) should] equal:theValue(1)]; [[theValue(numRows) should] equal:theValue(3)]; }); }); UpcomingDeparturesViewControllerSpec.m

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your turn test that: table view cells have the right data

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hints [departureVC tableView:cellForRowAtIndexPath:] tableViewCell.textLabel.text tableViewCell.detailTextLabel.text BREAK after this

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~ BREAK? ~

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test doubles (mocks/stubs)

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$> git checkout sl-4 $> git clean -dxf 1: Close XCode 2: 3: Open Run2Bart.xcworkspace

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UpcomingDeparturesViewController.m - (void)viewWillAppear:(BOOL)animated{ [self refreshUpcomingDepartures]; } - (void) refreshUpcomingDepartures{ [self.refreshControl beginRefreshing]; [self.bartClient fetchUpcomingDeparturesForStation:self.station success:^(NSArray *departures) { [self.refreshControl endRefreshing]; self.departures = departures; [self.tableView reloadData]; } failure:^(NSError *error) { [self.refreshControl endRefreshing]; }]; }

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Dependencies in Unit Tests

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API UI Business Logic

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API UI Business Logic SUT

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API UI Business Logic SUT

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API UI Business Logic SUT

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API UI Business Logic SUT TD TD

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SUT TD TD

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API UI Business Logic SUT

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API UI Business Logic SUT View Controller

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API UI Business Logic SUT BartClient View Controller

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API UI Business Logic SUT TD

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API UI Business Logic SUT TD View Controller

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API UI Business Logic SUT TD Spy BartClient View Controller

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- (void)viewWillAppear:(BOOL)animated{ [self refreshUpcomingDepartures]; } - (void) refreshUpcomingDepartures{ [self.refreshControl beginRefreshing]; [self.bartClient fetchUpcomingDeparturesForStation:self.station success:^(NSArray *departures) { [self.refreshControl endRefreshing]; self.departures = departures; [self.tableView reloadData]; } failure:^(NSError *error) { [self.refreshControl endRefreshing]; }]; } UpcomingDeparturesViewController.m

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@interface SpyBartClient : NSObject{ BOOL _fetchWasCalled; } @end @implementation SpyBartClient - (id)init { self = [super init]; if (self) { _fetchWasCalled = NO; } return self; } - (void)fetchUpcomingDeparturesForStation:(Station *)station success:(FetchSuccessBlock)success failure:(FetchFailureBlock)failure{ _fetchWasCalled = YES; } - (BOOL)fetchUpcomingDeparturesWasCalled{ return _fetchWasCalled; } @end UpcomingDeparturesViewControllerSpec.m

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describe(@"the VC's view appearing", ^{ it( @"asks the api client to load the upcoming departures", ^{ SpyBartClient *testDoubleBartClient = [[SpyBartClient alloc] init]; departuresVC.bartClient = testDoubleBartClient; [departuresVC viewWillAppear:YES]; [[theValue([testDoubleBartClient fetchUpcomingDeparturesWasCalled]) should] beTrue]; }); }); UpcomingDeparturesViewControllerSpec.m

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API UI Business Logic SUT TD Spy BartClient View Controller

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from hand-rolled to dynamic

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UpcomingDeparturesViewControllerSpec.m id mockBartClient = [KWMock mockForProtocol:@protocol(BartClient)];

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UpcomingDeparturesViewControllerSpec.m it( @"asks the api client to load the upcoming departures", ^{ id mockBartClient = [KWMock mockForProtocol:@protocol(BartClient)]; departuresVC.bartClient = mockBartClient; [[mockBartClient should] receive:@selector(fetchUpcomingDeparturesForStation:success:failure:) andReturn:nil]; [departuresVC viewWillAppear:YES]; });

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it( @"asks the api client to load the upcoming departures", ^{ id mockBartClient = [KWMock mockForProtocol:@protocol(BartClient)]; departuresVC.bartClient = mockBartClient; [[mockBartClient should] receive:@selector(fetchUpcomingDeparturesForStation:success:failure:) andReturn:nil]; [departuresVC viewWillAppear:YES]; }); it( @"asks the api client to load the upcoming departures", ^{ SpyBartClient *testDoubleBartClient = [[SpyBartClient alloc] init]; departuresVC.bartClient = testDoubleBartClient; [departuresVC viewWillAppear:YES]; [[theValue([testDoubleBartClient fetchUpcomingDeparturesWasCalled] should] beTrue]; }); hand-rolled dynamic

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verifying what has been sent to a test double

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UpcomingDeparturesViewControllerSpec.m it( @"asks the api client to load the upcoming departures for the right station", ^{ id mockBartClient = [KWMock mockForProtocol:@protocol(BartClient)]; departuresVC.bartClient = mockBartClient; [[[mockBartClient should] receive] fetchUpcomingDeparturesForStation:station success:any() failure:any()]; [departuresVC viewWillAppear:YES]; });

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another way to think about mocks/stubs

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system under test in out

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D e p e n d e n c y system under test indirect output indirect input direct input direct output T e s t

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API UI Business Logic SUT BartClient View Controller

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API UI Business Logic SUT

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usiness ogic SUT SUT TD Test

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D e p e n d e n c y system under test indirect output indirect input direct input direct output T e s t values passed to dependency via method call values returned from call to dependency

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~ BREAK? ~

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DRYing up your test code

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$> git checkout sl-3 $> git clean -dxf 1: Close XCode 2: 3: Open Run2Bart.xcworkspace

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Don’t Repeat Yourself

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describe( @"UpcomingDeparturesViewController ", ^{ it( @"has the station's name as the title", ^{ // Given Station *theStation = [[Station alloc] initWithName:@"station name" abbr:@"station-abbr"]; UpcomingDeparturesViewController *theDeparturesVC = [[UpcomingDeparturesViewController alloc] initForStation:theStation]; // Then [[theDeparturesVC.title should] equal:@"station name"]; }); // ... UpcomingDeparturesViewControllerSpec.m

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describe( @"UpcomingDeparturesViewController ", ^{ __block Station *station; __block UpcomingDeparturesViewController *departuresVC; beforeEach(^{ station = [[Station alloc] initWithName:@"station name" abbr:@"station-abbr"]; departuresVC = [[UpcomingDeparturesViewController alloc] initForStation:station]; }) it( @"has the station's name as the title", ^{ // Then [[departuresVC.title should] equal:station.name]; }); // ... UpcomingDeparturesViewControllerSpec.m

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your turn: DRY it up UpcomingDeparturesViewControllerSpec.m introduce a beforeEach block change tests in the ﬁle to take advantage of it