Testing in iOS - mobile-warsaw.pl · TDD • Test Driven ... Testing in iOS 21 Thursday, July 4, 13. Unit Tests 22 Thursday, July 4, 13. OCUnit 23

Testing in iOSPaweł Dudek

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Thursday, July 4, 13

Why do we want to write tests?

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Reasons for testing

• Striving for better software

• Faster development cycles

• Being “confident” about your code

• Leads to better, more modularized codebase

• Less code to write

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Common misconceptions

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Common misconceptions

• “It will take longer to write code” or “Time spent writing/refactoring tests is time lost”

• “It will take more time to modify existing system”

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Reasons for testing

• Striving for better software

• Faster development cycles

• Being “confident” about your code

• Leads to better, more modularized codebase

• Less code to write

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Am I going to write poor software if I don’t

do tests?

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Are unit tests an invaluable tool for writing great software? Heck yes. Am I going to produce a poor product if I can’t unit test? Hell no.

Jonathan Rasmusson

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Now that we know that writing tests is a

good idea...

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How can we do it?

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• You will feel confused

• You won’t know how to start

• You will need help

• Conclusion: it’s not easy to start

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Warning

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Tips

• Never think of tests as tests

• Think of a scenario, behavior, example

• Grab a mature project from github with tests included

• Find someone experienced and ask questions

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Get on with it!How can we test?

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TDD

• Test Driven Development

• Red, Green, Refactor

• Write failing test first

• Fix it

• Refactor

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BDDBehavior Driven Development

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How does BDD differ from TDD?

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BDD builds upon TDD by formalising the good habits of the best TDD practitioners.

Matt Wynne,XP Evangelist

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Good habits

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• Work outside-in

• Use examples

• Use ubiquitous language

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A little bit of terminology...

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Terminology

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• Mocking (mocks & stubs)

• Expecting

• Matching

• Faking

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Testing in iOS

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Unit Tests

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OCUnit

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• Oldest Mac testing framework - officially supported by Apple since 2005

• Integrated with XCode

• Built-in assertion macros

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OCUnit Syntax

• All test classes inherit from SenTestCase

• All tests begin with test

• Setup and teardown method

• Everything else is ignored by testing framework

• Means you can use as additional setup methods!

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-(void)testFullName { Person *person = [Person person]; person.firstName = @"Mariusz"; person.secondName = @"Testowniczek"; NSString *fullName = [person fullName]; NSString *expectedName = @"Mariusz Testowniczek"; STAssertTrue([fullName isEqualToString:expectedName], @"");}

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OCUnit

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Behavior “Tests”

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Kiwi and Cedar

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• Nearly the same syntax

• Built-in stubs/mocks

• Built-in matchers

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SPEC_BEGIN(PersonSpec)

describe(@"Person", ^{ __block Person *person;

beforeEach(^{ person = [[Person alloc] init]; person.firstName = @"Mariusz"; person.lastName = @"Fixture Last Name"; });

describe(@"full name", ^{

__block NSString *fullName;

beforeEach(^{ fullName = [person fullName]; });

it(@"should return the full name", ^{ expect(fullName).to(equal(@"Mariusz Testowniczek")); }); });});

SPEC_END

Kiwi and Cedar Syntax

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SPEC_BEGIN(PersonSpec)

describe(@"Person", ^{ __block Person *person;

beforeEach(^{ person = [[Person alloc] init]; person.firstName = @"Mariusz"; person.lastName = @"Fixture Last Name"; });

describe(@"full name", ^{

__block NSString *fullName;

beforeEach(^{ fullName = [person fullName]; });

it(@"should return the full name", ^{ expect(fullName).to(equal(@"Mariusz Testowniczek")); }); });});

SPEC_ENDThursday, July 4, 13

Example

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CedarTaptera Additions

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The action block

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The action block

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• Syntax addition to previous blocks

• Executed after all beforeEach’s for given example are run

• Really useful when chaining behavior tests

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Describe

Describe

beforeEach

action

Describe

beforeEach

action

beforeEach

action

it

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Example

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Helper libraries

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Helper libraries

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• Mocking: OCMock, OCMockito, LRMockey

• Expecting: Expecta

• Matching: OCHamcrest

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Most the presented libraries offer similar

functionalityIt all depends on syntax.

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iOS Testing Tips

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Testing UI Layout

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• Hard to maintain (as can change rapidly when GD goes on a rampage)

• Gives little value (quickly noticed by QA if something is off)

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System Singletons

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• Makes hard to test if accessed directly

• Nice candidate for putting in a property

[UIDevice currentDevice][UIScreen mainScreen]

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UIViewController transitions

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• Pushing new view controllers on nav controller stack or using transitions API

• Use helper class

• Tests - check if a given method was called on the helper class

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Testing UIView animations

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• Easiest way is to use the block-based API

• Helper class similar to transitions

• Tests - use fake to immediately call the animation block

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Common caveats

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• Don’t set mocks on [UIViewController view]

• Avoid using categories to override system properties or existing behavior

• Keychain and most of system objects are unavailable when tests are run from command line w/o simulator

• iOS 5.x Simulator is broken for NSProxy subclasses in weak properties

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Things worth talking about but cut due to time limitations

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• Frank / KIF - Application Tests

• Specta - yet another BDD style testing framework

• Dependency injection

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Summary

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Summary

• Testing is a great way to help developers

• Better codebase, faster iterations

• Invaluable for larger projects

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Resources & Contact

@eldudi

github.com/paweldudek

pawel@dudek.mobi

Code Examples

Contact

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