Unit testing in iOS featuring OCUnit, GHUnit & OCMock

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

@hpique

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

Agenda

• Unit testing
• OCUnit
• GHUnit
• OCMock
• Proﬁt!

unit test
=
code that tests a single unit
of code

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");
}

Reasons not to unit
test

ReasonsExcuses not
to unit test

Excuses

• “I don’t need it”
• “Deadline is too tight”
• “It’s not applicable for this [project|
class|method]”

• “Unit testing in Xcode sucks”

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

quality code and testable
code are best buds

When?

• After writing code
• Before writing code (TDD)
• After ﬁxing a bug

Deﬁnitions
Test Suite

SetUp

Test Case Test Case Test Case

TearDown

OCUnit

• De-facto unit testing framework for
Obj-C

• Xcode provides native support

Unit testing in iOS featuring OCUnit, GHUnit & OCMock

#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

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

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.
Test Suite 'All tests' finished at 2011-12-09 11:43:01 +0000.

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, ...)

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, ...)

Let’s see some code!

github.com/hpique/Unit-Testing-in-iOS-Sample-Code

GHUnit
• The other Unit Testing framework for
Obj-C

• Open-source: github.com/gabriel/gh-
unit

• GUI!
• No Xcode native support
• Compatible with OCUnit

#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

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, ...)

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

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

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

3. Modify Other Link
Flags

• Add -all_load
• Add -ObjC

4. Change AppDelegate
1. Remove default AppDelegate
2. Modify main.m:

int main(int argc, char *argv[])
{
@autoreleasepool {
return UIApplicationMain(argc, argv, nil,
@"GHUnitIOSAppDelegate");
}
}

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

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

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

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”

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

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];
}

Unit testing in iOS featuring OCUnit, GHUnit & OCMock

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