This document provides an overview and introduction to unit testing in iOS. It discusses OCUnit, GHUnit and OCMock, which are common frameworks for unit testing, mock objects, and assertions in Objective-C and iOS. The key points covered include: - OCUnit is the default unit testing framework for Objective-C, with built-in support in Xcode. - GHUnit is an alternative open source framework that provides a GUI runner and additional macros. - OCMock allows mocking objects to control and isolate dependencies in tests. - Examples are provided of writing tests with OCUnit, GHUnit and using mock objects with OCMock. - Reasons for unit testing like fixing bugs early and easier

1. Unit Testing in iOS
featuring OCUnit, GHUnit & OCMock
works for OS X too!
@hpique

2. The sad fate of developers who don’t write unit tests

3. Agenda
• Unit testing
• OCUnit
• GHUnit
• OCMock
• Profit!

4. unit test
=
code that tests a single unit
of code

5. Hey look! A unit test!
- (void) testColorFromPointAndSize_SizeZero
{
// Prepare input
CGSize size = CGSizeZero;
CGPoint point = CGPointZero;
// Do something
UIColor *color = [_viewController colorFromPoint:point andSize:size];
// Validate output
STAssertNil(color, @"Color must be nil when size is zero");
}

6. Reasons not to unit
test

7. ...

8. ReasonsExcuses not
to unit test

9. Excuses
• “I don’t need it”
• “Deadline is too tight”
• “It’s not applicable for this [project|
class|method]”
• “Unit testing in Xcode sucks”

10. Reasons to unit test
• Fix bugs early
• Refine design
• Easier to make changes
• Instant gratification :)
• Useful documentation
• Reduce testing time

11. quality code and testable
code are best buds

12. When?
• After writing code
• Before writing code (TDD)
• After fixing a bug

13. Definitions
Test Suite
SetUp
Test Case Test Case Test Case
TearDown

14. Agenda
• Unit testing
• OCUnit
• GHUnit
• OCMock
• Profit!

15. OCUnit
• De-facto unit testing framework for
Obj-C
• Xcode provides native support

18. +N

19. #import <SenTestingKit/SenTestingKit.h>
@interface HelloWorldTests : SenTestCase
@end
@implementation HelloWorldTests
- (void)setUp
{
[super setUp];
// Set-up code here.
}
- (void)tearDown
{
// Tear-down code here.
[super tearDown];
}
- (void)testExample
{
STFail(@"Unit tests are not implemented yet in HelloWorldTests");
}
@end

20. Writing tests with
OCUnit
• Each Test Suite is a class that inherits
from SenTestCase
• Each Test Case is a method with prefix
test
• setUp & tearDown are optional

21. +U

22. Console output
2011-12-09 12:43:01.394 HelloWorld[2858:fb03] Applications are expected to have a
root view controller at the end of application launch
Test Suite 'All tests' started at 2011-12-09 11:43:01 +0000
Test Suite '/Users/hermespique/Library/Developer/Xcode/DerivedData/HelloWorld-
ezilismrgmrzecbbsndapbyeczre/Build/Products/Debug-iphonesimulator/
HelloWorldTests.octest(Tests)' started at 2011-12-09 11:43:01 +0000
Test Suite 'HelloWorldTests' started at 2011-12-09 11:43:01 +0000
Test Case '-[HelloWorldTests testExample]' started.
/Users/hermespique/Documents/workspace/HelloWorld/HelloWorldTests/
HelloWorldTests.m:33: error: -[HelloWorldTests testExample] : Unit tests are not
implemented yet in HelloWorldTests
Test Case '-[HelloWorldTests testExample]' failed (0.000 seconds).
Test Suite 'HelloWorldTests' finished at 2011-12-09 11:43:01 +0000.
Executed 1 test, with 1 failure (0 unexpected) in 0.000 (0.000) seconds
Test Suite '/Users/hermespique/Library/Developer/Xcode/DerivedData/HelloWorld-
ezilismrgmrzecbbsndapbyeczre/Build/Products/Debug-iphonesimulator/
HelloWorldTests.octest(Tests)' finished at 2011-12-09 11:43:01 +0000.
Executed 1 test, with 1 failure (0 unexpected) in 0.000 (0.000) seconds
Test Suite 'All tests' finished at 2011-12-09 11:43:01 +0000.
Executed 1 test, with 1 failure (0 unexpected) in 0.000 (0.001) seconds

23. OCUnit Macros
STAssertEqualObjects(a1, a2, description, ...)
STAssertEquals(a1, a2, description, ...)
STAssertEqualsWithAccuracy(a1, a2, accuracy, description, ...)
STFail(description, ...)
STAssertNil(a1, description, ...)
STAssertNotNil(a1, description, ...)
STAssertTrue(expr, description, ...)
STAssertTrueNoThrow(expr, description, ...)
STAssertFalse(expr, description, ...)
STAssertFalseNoThrow(expr, description, ...)
STAssertThrows(expr, description, ...)
STAssertThrowsSpecific(expr, specificException, description, ...)
STAssertThrowsSpecificNamed(expr, specificException, aName, description, ...)
STAssertNoThrow(expr, description, ...)
STAssertNoThrowSpecific(expr, specificException, description, ...)
STAssertNoThrowSpecificNamed(expr, specificException, aName, description, ...)

24. Most used macros
STAssertTrue(expr, description, ...)
STAssertFalse(expr, description, ...)
STAssertNil(a1, description, ...)
STAssertNotNil(a1, description, ...)
STAssertEqualObjects(a1, a2, description, ...)
STAssertEquals(a1, a2, description, ...)
STFail(description, ...)
STAssertThrows(expr, description, ...)

25. Let’s see some code!
github.com/hpique/Unit-Testing-in-iOS-Sample-Code

26. Agenda
• Unit testing
• OCUnit
• GHUnit
• OCMock
• Profit!

27. GHUnit
• The other Unit Testing framework for
Obj-C
• Open-source: github.com/gabriel/gh-
unit
• GUI!
• No Xcode native support
• Compatible with OCUnit

29. #import <GHUnitIOS/GHUnit.h>
@interface ExampleTest : GHTestCase
@end
@implementation ExampleTest
- (BOOL)shouldRunOnMainThread {
return NO;
}
- (void)setUpClass {
// Run at start of all tests in the class
}
- (void)setUp {
// Run before each test method
}
- (void)tearDown {
// Run after each test method
}
- (void)tearDownClass {
// Run at end of all tests in the class
}
- (void)testFoo {
NSString *a = @"foo";
GHAssertNotNil(a, nil);
}
@end

30. If you’re into macros...
GHAssertNoErr(a1, description, ...) GHAssertEquals(a1, a2, description, ...)
GHAssertErr(a1, a2, description, ...) GHAbsoluteDifference(left,right)
GHAssertNotNULL(a1, description, ...) (MAX(left,right)-MIN(left,right))
GHAssertNULL(a1, description, ...) GHAssertEqualsWithAccuracy(a1, a2,
GHAssertNotEquals(a1, a2, description, ...) accuracy, description, ...)
GHAssertNotEqualObjects(a1, a2, desc, ...) GHFail(description, ...)
GHAssertOperation(a1, a2, op, GHAssertNil(a1, description, ...)
description, ...) GHAssertNotNil(a1, description, ...)
GHAssertGreaterThan(a1, a2, GHAssertTrue(expr, description, ...)
description, ...) GHAssertTrueNoThrow(expr,
GHAssertGreaterThanOrEqual(a1, a2, description, ...)
description, ...) GHAssertFalse(expr, description, ...)
GHAssertLessThan(a1, a2, description, ...) GHAssertFalseNoThrow(expr,
GHAssertLessThanOrEqual(a1, a2, description, ...)
description, ...) GHAssertThrows(expr, description, ...)
GHAssertEqualStrings(a1, a2, GHAssertThrowsSpecific(expr,
description, ...) specificException, description, ...)
GHAssertNotEqualStrings(a1, a2, GHAssertThrowsSpecificNamed(expr,
description, ...) specificException, aName,
GHAssertEqualCStrings(a1, a2, description, ...)
description, ...) GHAssertNoThrow(expr, description, ...)
GHAssertNotEqualCStrings(a1, a2, GHAssertNoThrowSpecific(expr,
description, ...) specificException, description, ...)
GHAssertEqualObjects(a1, a2, GHAssertNoThrowSpecificNamed(expr,
description, ...) specificException, aName,
description, ...)

31. GHUnitAsyncTestCase
#import <GHUnitIOS/GHUnit.h>
@interface AsyncTest : GHAsyncTestCase { }
@end
@implementation AsyncTest
- (void)testURLConnection {
[self prepare];
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://
www.google.com"]];
NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request
delegate:self startImmediately:YES];
[self waitForStatus:kGHUnitWaitStatusSuccess timeout:10.0];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
[self notify:kGHUnitWaitStatusSuccess forSelector:@selector(testURLConnection)];
}
@end

32. Configure GHUnit
1. Create target
2. Add GHUnitiOS.framework
2.1.and QuartzCore.framework!
3. Modify Other Linker Flags
4. Change AppDelegate

33. 1. Create target

34. 1. Create target

35. 2. Add
GHUnitiOS.framework
1. Download from github & unzip
2. > cd gh-unit/Project-iOS
3. > make
or
Download the latest stable framework from
github downloads

36. 3. Modify Other Link
Flags
• Add -all_load
• Add -ObjC

37. 4. Change AppDelegate
1. Remove default AppDelegate
2. Modify main.m:
int main(int argc, char *argv[])
{
@autoreleasepool {
return UIApplicationMain(argc, argv, nil,
@"GHUnitIOSAppDelegate");
}
}

38. +B

39. Let’s see some code!
github.com/hpique/Unit-Testing-in-iOS-Sample-Code

40. OCUnit vs GHUnit
OCUnit GHUnit
Xcode integration Built-in Manual
Console Console
Results
Contextual GUI
More macros
Development GHAsyncTestCase
Everything,
Execution Everything
selection or failed

41. Using OCUnit tests in
GHUnit target
1. Add OCUnit tests to target
2. Add tested files to target
3. Add SenTestKit.framework
4. Add this to Framework Search Paths
(order matters):
$(SDKROOT)/Developer/Library/Frameworks
$(DEVELOPER_LIBRARY_DIR)/Frameworks

42. Agenda
• Unit testing
• OCUnit
• GHUnit
• OCMock
• Profit!

43. mock object
=
simulated object that
mimics the behavior
of a real object in
controlled ways

44. When to mock an
object?
• supplies non-deterministic results (ie:
sensors)
• has states that are difficult to create or
reproduce (ie: a network error)
• is slow (ie: database)
• does not yet exist or may change behavior
• to avoid writing “test code”

45. OCMock
• De-facto mocking framework for Obj-C
• Open-source: github.com/erikdoe/
ocmock
• mock objects on the fly via the
trampoline pattern
• Complementary with OCUnit & GHUnit

46. Hey look! Mock objects!
- (void) testHandleGesture
{
// Prepare input and state
id viewMock = [OCMockObject partialMockForObject:_viewController.view];
CGRect viewFrame = CGRectMake(0, 0, 320, 480);
[[[viewMock stub] andReturnValue:OCMOCK_VALUE(viewFrame)] frame];
_viewController.view = viewMock;
UIGestureRecognizer *gesture = [[UITapGestureRecognizer alloc] init];
id gestureMock = [OCMockObject partialMockForObject:gesture];
CGPoint gesturePoint = CGPointMake(viewFrame.size.width / 2,
viewFrame.size.height / 2);
[[[gestureMock stub]
andReturnValue:OCMOCK_VALUE(gesturePoint)] locationInView:[OCMArg any]];
// Do something that changes state
[_viewController handleGesture:gestureMock];
// Validate state
UIColor *expectedColor = [UIColor colorWithRed:0.5 green:0.5 blue:0 alpha:1];
UIColor *color = _viewController.view.backgroundColor;
[self assertEqualsColor:expectedColor toColor:color];
}

47. Let’s see some code!
github.com/hpique/Unit-Testing-in-iOS-Sample-Code

48. Thanks!
@hpique