It All Starts With The Test

Why does a Google search for “ghunit test example” ask if I mean “junit test example”? Right there, that should have alerted me to how painful this endeavor would be. So far, I have been unimpressed with the documentation I have found for testing (among other things Objective-C related). As I mentioned in my previous post, I have found a few blog posts and user guides that I keep referring back to, however they are in no way complete (but getting better).

My first major task (which I would argue should not have been major) in this series, was to write my first unit test. I was only partly surprised that the book I bought had no references to testing in it. In talking with other developers, I was told ghunit was far and away a better choice than the standard OCUnit, so I went with it. I can’t imagine the pain I would have endured had I gone with OCUnit instead. I spent four nights writing a GHUnit test for a class with one method which would return the number one. It took me two nights to figure out that I had to “Start Tests” under the “Executables” folder. Just goes to show how unfamiliar I still am with the XCode IDE.

The Test

#import "TestDrivenObjectiveC.h"
#import <ghunit/GHUnit.h>
 
@interface TestDrivenObjectiveCTest : GHTestCase {}
@end
 
@implementation TestDrivenObjectiveCTest
 
-(void) testMethodReturning42DoesNotReturn43AndShouldFail{
	TestDrivenObjectiveC *something = [[TestDrivenObjectiveC alloc] init];
	int retVal = [something methodReturning42];
	GHAssertEquals(43, retVal, @"retVal is not equal to 43!");
}
 
-(void) testMethodReturning42Returns42AndShouldPass{
	TestDrivenObjectiveC *something = [[TestDrivenObjectiveC alloc] init];
	int retVal = [something methodReturning42];
	GHAssertEquals(42, retVal, @"retVal is not equal to 42!");
}
@end

The Code

#import <cocoa/Cocoa.h>
 
@interface TestDrivenObjectiveC : NSObject {
}
- (int) methodReturning42;
 
@end

#import "TestDrivenObjectiveC.h"
 
@implementation TestDrivenObjectiveC
 
- (int) methodReturning42{
	return 42;
}
 
@end

The Instructions

Prep Work

1. Copy GHUnit.framework from here to /Library/Frameworks/ within the Finder
2. Create a new project (Cocoa Application)
3. Create a new Target (Application – Cocoa) called UnitTests
4. In the Target “UnitTests” Info window that pops up, select the General tab
   1. Add GHUnit.framework
      1. Click the + to add a Linked Library
      2. Select GHUnit.framework and click Add
   2. Add your project as a dependency
      1. Click the + to add a Direct Dependency
      2. Select your project and click Add Target
   3. Close the Target “UnitTests” Info window
5. Copy GHUnitTestMain.m into the project
   1. Right click on UnitTests Target and choose Add->Existing Files…->browse to GHUnitTestMain.m
   2. Choose to add it only to the UnitTests Target and copy it into the project

Write a Test

1. Right click on the project and choose Add->New File…
2. Choose Objective-C class
3. Give the test a name
4. Keep only the UnitTests Target selected
5. Subclass GHTestCase
6. Add a test method

Write Some Testable Code

1. Right click on the project and choose Add->New File…
2. Choose Objective-C class
3. Give the class a name
4. Copy the testable code to the Unit Tests (this is awkward – probably a better way around this)
   1. Drag the testable .m files down into the UnitTests Compiled folder

Run the Test

1. Right click on the UnitTests target and click Build UnitTests
2. If that is successful, go to the Executables and right click and select Start UnitTests
3. When the window of unit tests opens, click the Run button
4. Watch for successful or failed tests!

When I started writing this post a few days ago, I still hadn’t found an excellent resource for what test assertions were available other than reading the source code. But after taking another crack at finding documentation, I ran across GHUnit documentation, which has been improved considerably with a dedicated site for the documentation and now includes information about the test macros.

Next Up

Something useful. More than one method returning the number 42. Somehow, I feel another challenge coming on…