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?
expect.
Makes refactoring much less painful

Why Unit Testing?
expect.
Makes refactoring much less painful
Forces you to write smaller, more
concise methods

2 Kinds of Unit Test
Bundles

Bundles
Application Test Bundle
Tests fully bootstrapped application

Bundles
Application Test Bundle
Tests fully bootstrapped application
Logic Test Bundle
Tests 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
⌘ + 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
A unit test bundle is created
alongside your main target

Setting Up
A separate Xcode group is
created for your unit tests

Setting Up
All tests should go inside the unit
test group

Setting Up
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

All unit test methods must begin with the
word “test”

word “test”
Unit test methods must have a return
type of void

word “test”
type of void
Unit test methods cannot have
parameters

word “test”
Unit test classes are subclasses of
SenTestCase
type of void
Unit test methods cannot have
parameters

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
needed in a project

To run some code prior to each unit test,
override the setup method
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 outcome
3.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 tests
Good 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?
ThankYou!
mark@markstruzinski.com
@ski081 (Twitter/ADN)
http://markstruzinski.com

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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