Beginning iOS unit testing

Beginning iOS Unit Testing

Mark Struzinski

Monday, April 22, 13

What is Unit Testing?



Test small pieces of your code (units) in isolation.



Test small pieces of your code (units) in isolation.

Usually, this means testing methods.


Why Unit Testing?


Why Unit Testing?

Verify your code does what you expect.


Why Unit Testing?


Makes refactoring much less painful


Why Unit Testing?


Makes refactoring much less painful

Forces you to write smaller, more concise methods


2 Kinds of Unit Test Bundles



Application Test BundleTests fully bootstrapped application



Application Test BundleTests fully bootstrapped application

Logic Test BundleTests classes in isolation


Setting Up


Setting Up

New projects offer an option to create unit tests immediately


Setting Up


Creates an Application unit test bundle


Setting Up


If at all possible, do this

Creates an Application unit test bundle


Setting Up


Setting Up

⌘ + U is automatically wired up to run tests


Setting Up


Can also use Product => Test from the menu


Setting Up


Builds and runs test bundle right from your app’s scheme

Can also use Product => Test from the menu


Setting Up


Setting UpA unit test bundle is created alongside your main target



A separate Xcode group is created for your unit tests



All tests should go inside the unit test group




All tests should go inside the unit test group


Usually, 1 unit test class per class under test


Adding New Tests


Adding New Tests

Add new files to unit testing group


Adding New Tests

Add new files to unit testing group

New file is under Cocoa Touch => Objective-C test case class


Running Tests


Running Tests

Initial test run will fail


Running Tests

Initial test run will fail

This is how you know it’s working


Unit Testing Conventions


Unit Testing ConventionsAll unit test methods must begin with the word “test”



Unit test methods must have a return type of void




Unit test methods cannot have parameters



Unit test classes are subclasses of SenTestCase


Unit test methods cannot have parameters


Unit Testing ConventionsCan have as many unit test classes/files as needed in a project



To run some code prior to each unit test, override the setup method

Can have as many unit test classes/files as needed in a project



To run some code prior to each unit test, override the setup method

Can have as many unit test classes/files as needed in a project

To run some code after each unit test, override the tearDown method


A Small Example


A Small Example

Tests use assertion macros to determine pass/fail


Assertion Macros

#define STAssertNil(a1, description, ...)#define STAssertNotNil(a1, description, ...)#define STAssertTrue(expression, description, ...)#define STAssertFalse(expression, description, ...)#define STAssertEqualObjects(a1, a2, description, ...)#define STAssertEquals(a1, a2, description, ...)#define STAssertEqualsWithAccuracy(left, right, accuracy, description, ...)#define STAssertThrows(expression, description, ...)#define STAssertThrowsSpecific(expression, specificException, description, ...)#define STAssertThrowsSpecificNamed(expr, specificException, aName, description, ...)#define STAssertNoThrow(expression, description, ...)#define STAssertNoThrowSpecific(expression, specificException, description, ...)#define STAssertNoThrowSpecificNamed(expr, specificException, aName, description, ...)#define STFail(description, ...)#define STAssertTrueNoThrow(expression, description, ...)#define STAssertFalseNoThrow(expression, description, ...)

(source:SenTestCase.h)


A Small Example

Anatomy of a Unit Test


A Small Example

1. Set up object to be tested



A Small Example



2. Set up any values for use in testing outcome


A Small Example



2. Set up any values for use in testing outcome3. Assert expected result


A Small Example

Setup/Teardown Methods


A Small Example

Run before and after each test



A Small Example



Use to set up objects and move repetitive code out of tests


A Small Example



Use to set up objects and move repetitive code out of testsGood way to ensure state of the object under test


Unit Test Failures


Unit Test Failures

Failure messages appear in the issue navigator and the console


Unit Test Failures


Good test log message go a long way to determining the issue


Unit Test Failures


Good test log message go a long way to determining the issue

This becomes even more important in apps with large test suites


Questions?


Questions?

Thank [email protected]

@ski081 (Twitter/ADN)

http://markstruzinski.com


mailto:[email protected]

mailto:[email protected]



Reference

https://developer.apple.com/library/ios/#documentation/DeveloperTools/Conceptual/UnitTesting/00-About_Unit_Testing/about.html






Beginning iOS unit testing

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